This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
remove redundant lex_end
[perl5.git] / regcomp.c
index 10e63f5..e0f65fa 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -2,7 +2,9 @@
  */
 
 /*
- * "A fair jaw-cracker dwarf-language must be."  --Samwise Gamgee
+ * 'A fair jaw-cracker dwarf-language must be.'            --Samwise Gamgee
+ *
+ *     [p.285 of _The Lord of the Rings_, II/iii: "The Ring Goes South"]
  */
 
 /* This file contains functions for compiling a regular expression.  See
@@ -57,7 +59,8 @@
  ****    Alterations to Henry's code are...
  ****
  ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 by Larry Wall and others
+ ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ ****    by Larry Wall and others
  ****
  ****    You may distribute under the terms of either the GNU General Public
  ****    License or the Artistic License, as specified in the README file.
@@ -82,6 +85,8 @@
 #  include "regcomp.h"
 #endif
 
+#include "dquote_static.c"
+
 #ifdef op
 #undef op
 #endif /* op */
 typedef struct RExC_state_t {
     U32                flags;                  /* are we folding, multilining? */
     char       *precomp;               /* uncompiled string. */
+    REGEXP     *rx_sv;                 /* The SV that is the regexp. */
     regexp     *rx;                    /* perl core regexp structure */
     regexp_internal    *rxi;           /* internal data for regexp object pprivate field */        
     char       *start;                 /* Start of input for compile */
@@ -128,7 +134,6 @@ typedef struct RExC_state_t {
     I32                orig_utf8;      /* whether the pattern was originally in utf8 */
                                /* XXX use this for future optimisation of case
                                 * where pattern must be upgraded to utf8. */
-    HV         *charnames;             /* cache of named sequences */
     HV         *paren_names;           /* Paren names */
     
     regnode    **recurse;              /* Recurse regops */
@@ -149,6 +154,7 @@ typedef struct RExC_state_t {
 
 #define RExC_flags     (pRExC_state->flags)
 #define RExC_precomp   (pRExC_state->precomp)
+#define RExC_rx_sv     (pRExC_state->rx_sv)
 #define RExC_rx                (pRExC_state->rx)
 #define RExC_rxi       (pRExC_state->rxi)
 #define RExC_start     (pRExC_state->start)
@@ -172,7 +178,6 @@ typedef struct RExC_state_t {
 #define RExC_seen_evals        (pRExC_state->seen_evals)
 #define RExC_utf8      (pRExC_state->utf8)
 #define RExC_orig_utf8 (pRExC_state->orig_utf8)
-#define RExC_charnames  (pRExC_state->charnames)
 #define RExC_open_parens       (pRExC_state->open_parens)
 #define RExC_close_parens      (pRExC_state->close_parens)
 #define RExC_opend     (pRExC_state->opend)
@@ -193,7 +198,10 @@ typedef struct RExC_state_t {
  */
 #define        WORST           0       /* Worst case. */
 #define        HASWIDTH        0x01    /* Known to match non-null strings. */
-#define        SIMPLE          0x02    /* Simple enough to be STAR/PLUS operand. */
+
+/* Simple enough to be STAR/PLUS operand, in an EXACT node must be a single
+ * character, and if utf8, must be invariant. */
+#define        SIMPLE          0x02
 #define        SPSTART         0x04    /* Starts with * or +. */
 #define TRYAGAIN       0x08    /* Weeded out a declaration. */
 #define POSTPONED      0x10    /* (?1),(?&name), (??{...}) or similar */
@@ -215,6 +223,11 @@ typedef struct RExC_state_t {
 #define PAREN_SET(u8str,paren) PBYTE(u8str,paren) |= PBITVAL(paren)
 #define PAREN_UNSET(u8str,paren) PBYTE(u8str,paren) &= (~PBITVAL(paren))
 
+/* If not already in utf8, do a longjmp back to the beginning */
+#define UTF8_LONGJMP 42 /* Choose a value not likely to ever conflict */
+#define REQUIRE_UTF8   STMT_START {                                       \
+                                     if (! UTF) JMPENV_JUMP(UTF8_LONGJMP); \
+                        } STMT_END
 
 /* About scan_data_t.
 
@@ -355,9 +368,10 @@ static const scan_data_t zero_scan_data =
 #define SCF_TRIE_RESTUDY        0x4000 /* Do restudy? */
 #define SCF_SEEN_ACCEPT         0x8000 
 
-#define UTF (RExC_utf8 != 0)
-#define LOC ((RExC_flags & RXf_PMf_LOCALE) != 0)
-#define FOLD ((RExC_flags & RXf_PMf_FOLD) != 0)
+#define UTF cBOOL(RExC_utf8)
+#define LOC cBOOL(RExC_flags & RXf_PMf_LOCALE)
+#define UNI_SEMANTICS cBOOL(RExC_flags & RXf_PMf_UNICODE)
+#define FOLD cBOOL(RExC_flags & RXf_PMf_FOLD)
 
 #define OOB_UNICODE            12345678
 #define OOB_NAMEDCLASS         -1
@@ -389,7 +403,7 @@ static const scan_data_t zero_scan_data =
     IV len = RExC_end - RExC_precomp;                                  \
                                                                        \
     if (!SIZE_ONLY)                                                    \
-       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);                      \
+       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx_sv);                   \
     if (len > RegexLengthToShowInErrorMessages) {                      \
        /* chop 10 shorter than the max, to ensure meaning of "..." */  \
        len = RegexLengthToShowInErrorMessages - 10;                    \
@@ -420,7 +434,7 @@ static const scan_data_t zero_scan_data =
  */
 #define        vFAIL(m) STMT_START {                           \
     if (!SIZE_ONLY)                                    \
-       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);      \
+       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx_sv);   \
     Simple_vFAIL(m);                                   \
 } STMT_END
 
@@ -438,7 +452,7 @@ static const scan_data_t zero_scan_data =
  */
 #define        vFAIL2(m,a1) STMT_START {                       \
     if (!SIZE_ONLY)                                    \
-       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);      \
+       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx_sv);   \
     Simple_vFAIL2(m, a1);                              \
 } STMT_END
 
@@ -457,7 +471,7 @@ static const scan_data_t zero_scan_data =
  */
 #define        vFAIL3(m,a1,a2) STMT_START {                    \
     if (!SIZE_ONLY)                                    \
-       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);      \
+       SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx_sv);   \
     Simple_vFAIL3(m, a1, a2);                          \
 } STMT_END
 
@@ -470,23 +484,22 @@ static const scan_data_t zero_scan_data =
            (int)offset, RExC_precomp, RExC_precomp + offset);  \
 } STMT_END
 
-#define        vWARN(loc,m) STMT_START {                                       \
+#define        ckWARNreg(loc,m) STMT_START {                                   \
     const IV offset = loc - RExC_precomp;                              \
-    Perl_warner(aTHX_ packWARN(WARN_REGEXP), "%s" REPORT_LOCATION,     \
-           m, (int)offset, RExC_precomp, RExC_precomp + offset);       \
+    Perl_ck_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,     \
+           (int)offset, RExC_precomp, RExC_precomp + offset);          \
 } STMT_END
 
-#define        vWARNdep(loc,m) STMT_START {                                    \
+#define        ckWARNregdep(loc,m) STMT_START {                                \
     const IV offset = loc - RExC_precomp;                              \
-    Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED, WARN_REGEXP),         \
-           "%s" REPORT_LOCATION,                                       \
-           m, (int)offset, RExC_precomp, RExC_precomp + offset);       \
+    Perl_ck_warner_d(aTHX_ packWARN2(WARN_DEPRECATED, WARN_REGEXP),    \
+           m REPORT_LOCATION,                                          \
+           (int)offset, RExC_precomp, RExC_precomp + offset);          \
 } STMT_END
 
-
-#define        vWARN2(loc, m, a1) STMT_START {                                 \
+#define        ckWARN2reg(loc, m, a1) STMT_START {                             \
     const IV offset = loc - RExC_precomp;                              \
-    Perl_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,                \
+    Perl_ck_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,     \
            a1, (int)offset, RExC_precomp, RExC_precomp + offset);      \
 } STMT_END
 
@@ -496,12 +509,24 @@ static const scan_data_t zero_scan_data =
            a1, a2, (int)offset, RExC_precomp, RExC_precomp + offset);  \
 } STMT_END
 
+#define        ckWARN3reg(loc, m, a1, a2) STMT_START {                         \
+    const IV offset = loc - RExC_precomp;                              \
+    Perl_ck_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,     \
+           a1, a2, (int)offset, RExC_precomp, RExC_precomp + offset);  \
+} STMT_END
+
 #define        vWARN4(loc, m, a1, a2, a3) STMT_START {                         \
     const IV offset = loc - RExC_precomp;                              \
     Perl_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,                \
            a1, a2, a3, (int)offset, RExC_precomp, RExC_precomp + offset); \
 } STMT_END
 
+#define        ckWARN4reg(loc, m, a1, a2, a3) STMT_START {                     \
+    const IV offset = loc - RExC_precomp;                              \
+    Perl_ck_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,     \
+           a1, a2, a3, (int)offset, RExC_precomp, RExC_precomp + offset); \
+} STMT_END
+
 #define        vWARN5(loc, m, a1, a2, a3, a4) STMT_START {                     \
     const IV offset = loc - RExC_precomp;                              \
     Perl_warner(aTHX_ packWARN(WARN_REGEXP), m REPORT_LOCATION,                \
@@ -630,6 +655,8 @@ S_scan_commit(pTHX_ const RExC_state_t *pRExC_state, scan_data_t *data, I32 *min
     const STRLEN old_l = CHR_SVLEN(*data->longest);
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_SCAN_COMMIT;
+
     if ((l >= old_l) && ((l > old_l) || (data->flags & SF_BEFORE_EOL))) {
        SvSetMagicSV(*data->longest, data->last_found);
        if (*data->longest == data->longest_fixed) {
@@ -676,6 +703,8 @@ S_scan_commit(pTHX_ const RExC_state_t *pRExC_state, scan_data_t *data, I32 *min
 STATIC void
 S_cl_anything(const RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
+    PERL_ARGS_ASSERT_CL_ANYTHING;
+
     ANYOF_CLASS_ZERO(cl);
     ANYOF_BITMAP_SETALL(cl);
     cl->flags = ANYOF_EOS|ANYOF_UNICODE_ALL;
@@ -689,6 +718,8 @@ S_cl_is_anything(const struct regnode_charclass_class *cl)
 {
     int value;
 
+    PERL_ARGS_ASSERT_CL_IS_ANYTHING;
+
     for (value = 0; value <= ANYOF_MAX; value += 2)
        if (ANYOF_CLASS_TEST(cl, value) && ANYOF_CLASS_TEST(cl, value + 1))
            return 1;
@@ -703,6 +734,8 @@ S_cl_is_anything(const struct regnode_charclass_class *cl)
 STATIC void
 S_cl_init(const RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
+    PERL_ARGS_ASSERT_CL_INIT;
+
     Zero(cl, 1, struct regnode_charclass_class);
     cl->type = ANYOF;
     cl_anything(pRExC_state, cl);
@@ -711,6 +744,8 @@ S_cl_init(const RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 STATIC void
 S_cl_init_zero(const RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
 {
+    PERL_ARGS_ASSERT_CL_INIT_ZERO;
+
     Zero(cl, 1, struct regnode_charclass_class);
     cl->type = ANYOF;
     cl_anything(pRExC_state, cl);
@@ -724,6 +759,7 @@ STATIC void
 S_cl_and(struct regnode_charclass_class *cl,
        const struct regnode_charclass_class *and_with)
 {
+    PERL_ARGS_ASSERT_CL_AND;
 
     assert(and_with->type == ANYOF);
     if (!(and_with->flags & ANYOF_CLASS)
@@ -762,6 +798,8 @@ S_cl_and(struct regnode_charclass_class *cl,
 STATIC void
 S_cl_or(const RExC_state_t *pRExC_state, struct regnode_charclass_class *cl, const struct regnode_charclass_class *or_with)
 {
+    PERL_ARGS_ASSERT_CL_OR;
+
     if (or_with->flags & ANYOF_INVERT) {
        /* We do not use
         * (B1 | CL1) | (!B2 & !CL2) = (B1 | !B2 & !CL2) | (CL1 | (!B2 & !CL2))
@@ -843,7 +881,7 @@ S_cl_or(const RExC_state_t *pRExC_state, struct regnode_charclass_class *cl, con
   Dumps the final compressed table form of the trie to Perl_debug_log.
   Used for debugging make_trie().
 */
+
 STATIC void
 S_dump_trie(pTHX_ const struct _reg_trie_data *trie, HV *widecharmap,
            AV *revcharmap, U32 depth)
@@ -851,8 +889,10 @@ S_dump_trie(pTHX_ const struct _reg_trie_data *trie, HV *widecharmap,
     U32 state;
     SV *sv=sv_newmortal();
     int colwidth= widecharmap ? 6 : 4;
+    U16 word;
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_DUMP_TRIE;
 
     PerlIO_printf( Perl_debug_log, "%*sChar : %-6s%-6s%-4s ",
         (int)depth * 2 + 2,"",
@@ -919,6 +959,13 @@ S_dump_trie(pTHX_ const struct _reg_trie_data *trie, HV *widecharmap,
         }
         PerlIO_printf( Perl_debug_log, "\n" );
     }
+    PerlIO_printf(Perl_debug_log, "%*sword_info N:(prev,len)=", (int)depth*2, "");
+    for (word=1; word <= trie->wordcount; word++) {
+       PerlIO_printf(Perl_debug_log, " %d:(%d,%d)",
+           (int)word, (int)(trie->wordinfo[word].prev),
+           (int)(trie->wordinfo[word].len));
+    }
+    PerlIO_printf(Perl_debug_log, "\n" );
 }    
 /*
   Dumps a fully constructed but uncompressed trie in list form.
@@ -935,6 +982,9 @@ S_dump_trie_interim_list(pTHX_ const struct _reg_trie_data *trie,
     SV *sv=sv_newmortal();
     int colwidth= widecharmap ? 6 : 4;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_DUMP_TRIE_INTERIM_LIST;
+
     /* print out the table precompression.  */
     PerlIO_printf( Perl_debug_log, "%*sState :Word | Transition Data\n%*s%s",
         (int)depth * 2 + 2,"", (int)depth * 2 + 2,"",
@@ -990,6 +1040,8 @@ S_dump_trie_interim_table(pTHX_ const struct _reg_trie_data *trie,
     SV *sv=sv_newmortal();
     int colwidth= widecharmap ? 6 : 4;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_DUMP_TRIE_INTERIM_TABLE;
     
     /*
        print out the table precompression so that we can do a visual check
@@ -1044,6 +1096,7 @@ S_dump_trie_interim_table(pTHX_ const struct _reg_trie_data *trie,
 
 #endif
 
+
 /* make_trie(startbranch,first,last,tail,word_count,flags,depth)
   startbranch: the first branch in the whole branch sequence
   first      : start branch of sequence of branch-exact nodes.
@@ -1224,20 +1277,20 @@ is the recommended Unicode-aware way of saying
     U16 dupe= trie->states[ state ].wordnum;                    \
     regnode * const noper_next = regnext( noper );              \
                                                                 \
-    if (trie->wordlen)                                          \
-        trie->wordlen[ curword ] = wordlen;                     \
     DEBUG_r({                                                   \
         /* store the word for dumping */                        \
         SV* tmp;                                                \
         if (OP(noper) != NOTHING)                               \
-            tmp = newSVpvn(STRING(noper), STR_LEN(noper));      \
+            tmp = newSVpvn_utf8(STRING(noper), STR_LEN(noper), UTF);   \
         else                                                    \
-            tmp = newSVpvn( "", 0 );                            \
-        if ( UTF ) SvUTF8_on( tmp );                            \
+            tmp = newSVpvn_utf8( "", 0, UTF );                 \
         av_push( trie_words, tmp );                             \
     });                                                         \
                                                                 \
     curword++;                                                  \
+    trie->wordinfo[curword].prev   = 0;                         \
+    trie->wordinfo[curword].len    = wordlen;                   \
+    trie->wordinfo[curword].accept = state;                     \
                                                                 \
     if ( noper_next < tail ) {                                  \
         if (!trie->jump)                                        \
@@ -1250,16 +1303,11 @@ is the recommended Unicode-aware way of saying
     }                                                           \
                                                                 \
     if ( dupe ) {                                               \
-        /* So it's a dupe. This means we need to maintain a   */\
-        /* linked-list from the first to the next.            */\
-        /* we only allocate the nextword buffer when there    */\
-        /* a dupe, so first time we have to do the allocation */\
-        if (!trie->nextword)                                    \
-            trie->nextword = (U16 *)                                   \
-               PerlMemShared_calloc( word_count + 1, sizeof(U16));     \
-        while ( trie->nextword[dupe] )                          \
-            dupe= trie->nextword[dupe];                         \
-        trie->nextword[dupe]= curword;                          \
+        /* It's a dupe. Pre-insert into the wordinfo[].prev   */\
+        /* chain, so that when the bits of chain are later    */\
+        /* linked together, the dups appear in the chain      */\
+       trie->wordinfo[curword].prev = trie->wordinfo[dupe].prev; \
+       trie->wordinfo[dupe].prev = curword;                    \
     } else {                                                    \
         /* we haven't inserted this word yet.                */ \
         trie->states[ state ].wordnum = curword;                \
@@ -1297,6 +1345,7 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
     regnode *jumper = NULL;
     regnode *nextbranch = NULL;
     regnode *convert = NULL;
+    U32 *prev_states; /* temp array mapping each state to previous one */
     /* we just use folder as a flag in utf8 */
     const U8 * const folder = ( flags == EXACTF
                        ? PL_fold
@@ -1318,6 +1367,8 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
 #endif
     SV *re_trie_maxbuff;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_MAKE_TRIE;
 #ifndef DEBUGGING
     PERL_UNUSED_ARG(depth);
 #endif
@@ -1330,6 +1381,9 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
     trie->charmap = (U16 *) PerlMemShared_calloc( 256, sizeof(U16) );
     if (!(UTF && folder))
        trie->bitmap = (char *) PerlMemShared_calloc( ANYOF_BITMAP_SIZE, 1 );
+    trie->wordinfo = (reg_trie_wordinfo *) PerlMemShared_calloc(
+                       trie->wordcount+1, sizeof(reg_trie_wordinfo));
+
     DEBUG_r({
         trie_words = newAV();
     });
@@ -1462,7 +1516,6 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
                (int)TRIE_CHARCOUNT(trie), trie->uniquecharcount,
                (int)trie->minlen, (int)trie->maxlen )
     );
-    trie->wordlen = (U32 *) PerlMemShared_calloc( word_count, sizeof(U32) );
 
     /*
         We now know what we are dealing with in terms of unique chars and
@@ -1486,6 +1539,9 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
     */
 
 
+    Newx(prev_states, TRIE_CHARCOUNT(trie) + 2, U32);
+    prev_states[1] = 0;
+
     if ( (IV)( ( TRIE_CHARCOUNT(trie) + 1 ) * trie->uniquecharcount + 1) > SvIV(re_trie_maxbuff) ) {
         /*
             Second Pass -- Array Of Lists Representation
@@ -1556,6 +1612,7 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
                         }
                         if ( ! newstate ) {
                             newstate = next_alloc++;
+                           prev_states[newstate] = state;
                             TRIE_LIST_PUSH( state, charid, newstate );
                             transcount++;
                         }
@@ -1739,6 +1796,8 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
                         if ( !trie->trans[ state + charid ].next ) {
                             trie->trans[ state + charid ].next = next_alloc;
                             trie->trans[ state ].check++;
+                           prev_states[TRIE_NODENUM(next_alloc)]
+                                   = TRIE_NODENUM(state);
                             next_alloc += trie->uniquecharcount;
                         }
                         state = trie->trans[ state + charid ].next;
@@ -1886,9 +1945,6 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
        PerlMemShared_realloc( trie->trans, trie->lasttrans
                               * sizeof(reg_trie_trans) );
 
-    /* and now dump out the compressed format */
-    DEBUG_TRIE_COMPILE_r(dump_trie(trie, widecharmap, revcharmap, depth+1));
-
     {   /* Modify the program and insert the new TRIE node*/ 
         U8 nodetype =(U8)(flags & 0xFF);
         char *str=NULL;
@@ -1973,7 +2029,7 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
                                     if ( folder )
                                         TRIE_BITMAP_SET(trie, folder[ *ch ]);
                                     DEBUG_OPTIMISE_r(
-                                        PerlIO_printf(Perl_debug_log, (char*)ch)
+                                        PerlIO_printf(Perl_debug_log, "%s", (char*)ch)
                                     );
                                }
                            }
@@ -2018,6 +2074,7 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
                    break;
                }
            }
+           trie->prefixlen = (state-1);
             if (str) {
                 regnode *n = convert+NODE_SZ_STR(convert);
                 NEXT_OFF(convert) = NODE_SZ_STR(convert);
@@ -2113,6 +2170,42 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
             Set_Node_Offset_Length(convert,mjd_offset,mjd_nodelen);
         });
     } /* end node insert */
+
+    /*  Finish populating the prev field of the wordinfo array.  Walk back
+     *  from each accept state until we find another accept state, and if
+     *  so, point the first word's .prev field at the second word. If the
+     *  second already has a .prev field set, stop now. This will be the
+     *  case either if we've already processed that word's accept state,
+     *  or that that state had multiple words, and the overspill words
+     *  were already linked up earlier.
+     */
+    {
+       U16 word;
+       U32 state;
+       U16 prev;
+
+       for (word=1; word <= trie->wordcount; word++) {
+           prev = 0;
+           if (trie->wordinfo[word].prev)
+               continue;
+           state = trie->wordinfo[word].accept;
+           while (state) {
+               state = prev_states[state];
+               if (!state)
+                   break;
+               prev = trie->states[state].wordnum;
+               if (prev)
+                   break;
+           }
+           trie->wordinfo[word].prev = prev;
+       }
+       Safefree(prev_states);
+    }
+
+
+    /* and now dump out the compressed format */
+    DEBUG_TRIE_COMPILE_r(dump_trie(trie, widecharmap, revcharmap, depth+1));
+
     RExC_rxi->data->data[ data_slot + 1 ] = (void*)widecharmap;
 #ifdef DEBUGGING
     RExC_rxi->data->data[ data_slot + TRIE_WORDS_OFFSET ] = (void*)trie_words;
@@ -2162,6 +2255,8 @@ S_make_trie_failtable(pTHX_ RExC_state_t *pRExC_state, regnode *source,  regnode
     reg_ac_data *aho;
     const U32 data_slot = add_data( pRExC_state, 1, "T" );
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_MAKE_TRIE_FAILTABLE;
 #ifndef DEBUGGING
     PERL_UNUSED_ARG(depth);
 #endif
@@ -2278,6 +2373,8 @@ S_join_exact(pTHX_ RExC_state_t *pRExC_state, regnode *scan, I32 *min, U32 flags
 #else
     PERL_UNUSED_ARG(depth);
 #endif
+
+    PERL_ARGS_ASSERT_JOIN_EXACT;
 #ifndef EXPERIMENTAL_INPLACESCAN
     PERL_UNUSED_ARG(flags);
     PERL_UNUSED_ARG(val);
@@ -2488,9 +2585,10 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
     regnode *first_non_open = scan;
     I32 stopmin = I32_MAX;
     scan_frame *frame = NULL;
-
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_STUDY_CHUNK;
+
 #ifdef DEBUGGING
     StructCopy(&zero_scan_data, &data_fake, scan_data_t);
 #endif
@@ -2792,13 +2890,18 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                                 }
                             } else {
 /* 
-    Currently we assume that the trie can handle unicode and ascii
-    matches fold cased matches. If this proves true then the following
-    define will prevent tries in this situation. 
-    
-    #define TRIE_TYPE_IS_SAFE (UTF || optype==EXACT)
-*/
+    Currently we do not believe that the trie logic can
+    handle case insensitive matching properly when the
+    pattern is not unicode (thus forcing unicode semantics).
+
+    If/when this is fixed the following define can be swapped
+    in below to fully enable trie logic.
+
 #define TRIE_TYPE_IS_SAFE 1
+
+*/
+#define TRIE_TYPE_IS_SAFE (UTF || optype==EXACT)
+
                                 if ( last && TRIE_TYPE_IS_SAFE ) {
                                     make_trie( pRExC_state, 
                                             startbranch, first, cur, tail, count, 
@@ -3024,7 +3127,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
            }
            flags &= ~SCF_DO_STCLASS;
        }
-       else if (strchr((const char*)PL_varies,OP(scan))) {
+       else if (REGNODE_VARIES(OP(scan))) {
            I32 mincount, maxcount, minnext, deltanext, fl = 0;
            I32 f = flags, pos_before = 0;
            regnode * const oscan = scan;
@@ -3104,7 +3207,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                /* These are the cases when once a subexpression
                   fails at a particular position, it cannot succeed
                   even after backtracking at the enclosing scope.
-               
+
                   XXXX what if minimal match and we are at the
                        initial run of {n,m}? */
                if ((mincount != maxcount - 1) && (maxcount != REG_INFTY))
@@ -3149,11 +3252,10 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                    (next_is_eval || !(mincount == 0 && maxcount == 1))
                    && (minnext == 0) && (deltanext == 0)
                    && data && !(data->flags & (SF_HAS_PAR|SF_IN_PAR))
-                   && maxcount <= REG_INFTY/3 /* Complement check for big count */
-                   && ckWARN(WARN_REGEXP))
+                   && maxcount <= REG_INFTY/3) /* Complement check for big count */
                {
-                   vWARN(RExC_parse,
-                         "Quantifier unexpected on zero-length expression");
+                   ckWARNreg(RExC_parse,
+                             "Quantifier unexpected on zero-length expression");
                }
 
                min += minnext * mincount;
@@ -3177,7 +3279,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
 
                    /* Skip open. */
                    nxt = regnext(nxt);
-                   if (!strchr((const char*)PL_simple,OP(nxt))
+                   if (!REGNODE_SIMPLE(OP(nxt))
                        && !(PL_regkind[OP(nxt)] == EXACT
                             && STR_LEN(nxt) == 1))
                        goto nogo;
@@ -3198,11 +3300,11 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
 
 #ifdef DEBUGGING
                    OP(nxt1 + 1) = OPTIMIZED; /* was count. */
-                   NEXT_OFF(nxt1+ 1) = 0; /* just for consistancy. */
-                   NEXT_OFF(nxt2) = 0; /* just for consistancy with CURLY. */
+                   NEXT_OFF(nxt1+ 1) = 0; /* just for consistency. */
+                   NEXT_OFF(nxt2) = 0; /* just for consistency with CURLY. */
                    OP(nxt) = OPTIMIZED;        /* was CLOSE. */
                    OP(nxt + 1) = OPTIMIZED; /* was count. */
-                   NEXT_OFF(nxt+ 1) = 0; /* just for consistancy. */
+                   NEXT_OFF(nxt+ 1) = 0; /* just for consistency. */
 #endif
                }
              nogo:
@@ -3225,12 +3327,10 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                        nxt = nxt2;
                    OP(nxt2)  = SUCCEED; /* Whas WHILEM */
                    /* Need to optimize away parenths. */
-                   if (data->flags & SF_IN_PAR) {
+                   if ((data->flags & SF_IN_PAR) && OP(nxt) == CLOSE) {
                        /* Set the parenth number.  */
                        regnode *nxt1 = NEXTOPER(oscan) + EXTRA_STEP_2ARGS; /* OPEN*/
 
-                       if (OP(nxt) != CLOSE)
-                           FAIL("Panic opt close");
                        oscan->flags = (U8)ARG(nxt);
                        if (RExC_open_parens) {
                            RExC_open_parens[ARG(nxt1)-1]=oscan; /*open->CURLYM*/
@@ -3248,7 +3348,6 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
 #if 0
                        while ( nxt1 && (OP(nxt1) != WHILEM)) {
                            regnode *nnxt = regnext(nxt1);
-                       
                            if (nnxt == nxt) {
                                if (reg_off_by_arg[OP(nxt1)])
                                    ARG_SET(nxt1, nxt2 - nxt1);
@@ -3315,12 +3414,9 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
 
                        if (UTF)
                            old = utf8_hop((U8*)s, old) - (U8*)s;
-                       
                        l -= old;
                        /* Get the added string: */
-                       last_str = newSVpvn(s  + old, l);
-                       if (UTF)
-                           SvUTF8_on(last_str);
+                       last_str = newSVpvn_utf8(s  + old, l, UTF);
                        if (deltanext == 0 && pos_before == b) {
                            /* What was added is a constant string */
                            if (mincount > 1) {
@@ -3405,13 +3501,13 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                if (flags & SCF_DO_STCLASS_AND) {
                     for (value = 0; value < 256; value++)
                         if (!is_VERTWS_cp(value))
-                            ANYOF_BITMAP_CLEAR(data->start_class, value);  
-                }                                                              
-                else {                                                         
+                            ANYOF_BITMAP_CLEAR(data->start_class, value);
+                }
+                else {
                     for (value = 0; value < 256; value++)
                         if (is_VERTWS_cp(value))
-                            ANYOF_BITMAP_SET(data->start_class, value);           
-                }                                                              
+                            ANYOF_BITMAP_SET(data->start_class, value);
+                }
                 if (flags & SCF_DO_STCLASS_OR)
                    cl_and(data->start_class, and_withp);
                flags &= ~SCF_DO_STCLASS;
@@ -3424,7 +3520,6 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                data->pos_delta += 1;
                data->longest = &(data->longest_float);
            }
-           
        }
        else if (OP(scan) == FOLDCHAR) {
            int d = ARG(scan)==0xDF ? 1 : 2;
@@ -3438,7 +3533,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                data->longest = &(data->longest_float);
            }
        }
-       else if (strchr((const char*)PL_simple,OP(scan))) {
+       else if (REGNODE_SIMPLE(OP(scan))) {
            int value = 0;
 
            if (flags & SCF_DO_SUBSTR) {
@@ -3482,19 +3577,37 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                    if (flags & SCF_DO_STCLASS_AND) {
                        if (!(data->start_class->flags & ANYOF_LOCALE)) {
                            ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NALNUM);
-                           for (value = 0; value < 256; value++)
-                               if (!isALNUM(value))
-                                   ANYOF_BITMAP_CLEAR(data->start_class, value);
+                            if (FLAGS(scan) & USE_UNI) {
+                                for (value = 0; value < 256; value++) {
+                                    if (!isWORDCHAR_L1(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            } else {
+                                for (value = 0; value < 256; value++) {
+                                    if (!isALNUM(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            }
                        }
                    }
                    else {
                        if (data->start_class->flags & ANYOF_LOCALE)
                            ANYOF_CLASS_SET(data->start_class,ANYOF_ALNUM);
-                       else {
-                           for (value = 0; value < 256; value++)
-                               if (isALNUM(value))
-                                   ANYOF_BITMAP_SET(data->start_class, value);                 
-                       }
+                        else if (FLAGS(scan) & USE_UNI) {
+                            for (value = 0; value < 256; value++) {
+                                if (isWORDCHAR_L1(value)) {
+                                    ANYOF_BITMAP_SET(data->start_class, value);
+                                }
+                            }
+                        } else {
+                            for (value = 0; value < 256; value++) {
+                                if (isALNUM(value)) {
+                                    ANYOF_BITMAP_SET(data->start_class, value);
+                                }
+                            }
+                        }
                    }
                    break;
                case ALNUML:
@@ -3511,9 +3624,19 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                    if (flags & SCF_DO_STCLASS_AND) {
                        if (!(data->start_class->flags & ANYOF_LOCALE)) {
                            ANYOF_CLASS_CLEAR(data->start_class,ANYOF_ALNUM);
-                           for (value = 0; value < 256; value++)
-                               if (isALNUM(value))
-                                   ANYOF_BITMAP_CLEAR(data->start_class, value);
+                            if (FLAGS(scan) & USE_UNI) {
+                                for (value = 0; value < 256; value++) {
+                                    if (isWORDCHAR_L1(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            } else {
+                                for (value = 0; value < 256; value++) {
+                                    if (isALNUM(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                           }
                        }
                    }
                    else {
@@ -3522,7 +3645,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                        else {
                            for (value = 0; value < 256; value++)
                                if (!isALNUM(value))
-                                   ANYOF_BITMAP_SET(data->start_class, value);                 
+                                   ANYOF_BITMAP_SET(data->start_class, value);
                        }
                    }
                    break;
@@ -3540,18 +3663,37 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                    if (flags & SCF_DO_STCLASS_AND) {
                        if (!(data->start_class->flags & ANYOF_LOCALE)) {
                            ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NSPACE);
-                           for (value = 0; value < 256; value++)
-                               if (!isSPACE(value))
-                                   ANYOF_BITMAP_CLEAR(data->start_class, value);
+                           if (FLAGS(scan) & USE_UNI) {
+                                for (value = 0; value < 256; value++) {
+                                    if (!isSPACE_L1(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            } else {
+                                for (value = 0; value < 256; value++) {
+                                    if (!isSPACE(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            }
                        }
                    }
                    else {
-                       if (data->start_class->flags & ANYOF_LOCALE)
+                        if (data->start_class->flags & ANYOF_LOCALE) {
                            ANYOF_CLASS_SET(data->start_class,ANYOF_SPACE);
-                       else {
-                           for (value = 0; value < 256; value++)
-                               if (isSPACE(value))
-                                   ANYOF_BITMAP_SET(data->start_class, value);                 
+                        }
+                        else if (FLAGS(scan) & USE_UNI) {
+                            for (value = 0; value < 256; value++) {
+                                if (isSPACE_L1(value)) {
+                                    ANYOF_BITMAP_SET(data->start_class, value);
+                                }
+                            }
+                        } else {
+                            for (value = 0; value < 256; value++) {
+                                if (isSPACE(value)) {
+                                    ANYOF_BITMAP_SET(data->start_class, value);
+                                }
+                            }
                        }
                    }
                    break;
@@ -3569,19 +3711,38 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                    if (flags & SCF_DO_STCLASS_AND) {
                        if (!(data->start_class->flags & ANYOF_LOCALE)) {
                            ANYOF_CLASS_CLEAR(data->start_class,ANYOF_SPACE);
-                           for (value = 0; value < 256; value++)
-                               if (isSPACE(value))
-                                   ANYOF_BITMAP_CLEAR(data->start_class, value);
+                            if (FLAGS(scan) & USE_UNI) {
+                                for (value = 0; value < 256; value++) {
+                                    if (isSPACE_L1(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            } else {
+                                for (value = 0; value < 256; value++) {
+                                    if (isSPACE(value)) {
+                                        ANYOF_BITMAP_CLEAR(data->start_class, value);
+                                    }
+                                }
+                            }
                        }
                    }
                    else {
                        if (data->start_class->flags & ANYOF_LOCALE)
                            ANYOF_CLASS_SET(data->start_class,ANYOF_NSPACE);
-                       else {
-                           for (value = 0; value < 256; value++)
-                               if (!isSPACE(value))
-                                   ANYOF_BITMAP_SET(data->start_class, value);                 
-                       }
+                        else if (FLAGS(scan) & USE_UNI) {
+                            for (value = 0; value < 256; value++) {
+                                if (!isSPACE_L1(value)) {
+                                    ANYOF_BITMAP_SET(data->start_class, value);
+                                }
+                            }
+                        }
+                        else {
+                            for (value = 0; value < 256; value++) {
+                                if (!isSPACE(value)) {
+                                    ANYOF_BITMAP_SET(data->start_class, value);
+                                }
+                            }
+                        }
                    }
                    break;
                case NSPACEL:
@@ -3611,7 +3772,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                        else {
                            for (value = 0; value < 256; value++)
                                if (isDIGIT(value))
-                                   ANYOF_BITMAP_SET(data->start_class, value);                 
+                                   ANYOF_BITMAP_SET(data->start_class, value);
                        }
                    }
                    break;
@@ -3628,7 +3789,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                        else {
                            for (value = 0; value < 256; value++)
                                if (!isDIGIT(value))
-                                   ANYOF_BITMAP_SET(data->start_class, value);                 
+                                   ANYOF_BITMAP_SET(data->start_class, value);
                        }
                    }
                    break;
@@ -3699,11 +3860,22 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                     data->whilem_c = data_fake.whilem_c;
                 }
                 if (f & SCF_DO_STCLASS_AND) {
-                    const int was = (data->start_class->flags & ANYOF_EOS);
-
-                    cl_and(data->start_class, &intrnl);
-                    if (was)
-                        data->start_class->flags |= ANYOF_EOS;
+                   if (flags & SCF_DO_STCLASS_OR) {
+                       /* OR before, AND after: ideally we would recurse with
+                        * data_fake to get the AND applied by study of the
+                        * remainder of the pattern, and then derecurse;
+                        * *** HACK *** for now just treat as "no information".
+                        * See [perl #56690].
+                        */
+                       cl_init(pRExC_state, data->start_class);
+                   }  else {
+                       /* AND before and after: combine and continue */
+                       const int was = (data->start_class->flags & ANYOF_EOS);
+
+                       cl_and(data->start_class, &intrnl);
+                       if (was)
+                           data->start_class->flags |= ANYOF_EOS;
+                   }
                 }
            }
 #if PERL_ENABLE_POSITIVE_ASSERTION_STUDY
@@ -4050,6 +4222,8 @@ S_add_data(RExC_state_t *pRExC_state, U32 n, const char *s)
 {
     U32 count = RExC_rxi->data ? RExC_rxi->data->count : 0;
 
+    PERL_ARGS_ASSERT_ADD_DATA;
+
     Renewc(RExC_rxi->data,
           sizeof(*RExC_rxi->data) + sizeof(void*) * (count + n - 1),
           char, struct reg_data);
@@ -4129,10 +4303,13 @@ extern const struct regexp_engine my_reg_engine;
 
 #ifndef PERL_IN_XSUB_RE 
 REGEXP *
-Perl_pregcomp(pTHX_ const SV * const pattern, const U32 flags)
+Perl_pregcomp(pTHX_ SV * const pattern, const U32 flags)
 {
     dVAR;
     HV * const table = GvHV(PL_hintgv);
+
+    PERL_ARGS_ASSERT_PREGCOMP;
+
     /* Dispatch a request to compile a regexp to correct 
        regexp engine. */
     if (table) {
@@ -4152,40 +4329,87 @@ Perl_pregcomp(pTHX_ const SV * const pattern, const U32 flags)
 #endif
 
 REGEXP *
-Perl_re_compile(pTHX_ const SV * const pattern, const U32 pm_flags)
+Perl_re_compile(pTHX_ SV * const pattern, U32 pm_flags)
 {
     dVAR;
-    register REGEXP *r;
+    REGEXP *rx;
+    struct regexp *r;
     register regexp_internal *ri;
     STRLEN plen;
-    char*  exp = SvPV((SV*)pattern, plen);
-    char* xend = exp + plen;
+    char  *exp;
+    char* xend;
     regnode *scan;
     I32 flags;
     I32 minlen = 0;
     I32 sawplus = 0;
     I32 sawopen = 0;
+    U8 jump_ret = 0;
+    dJMPENV;
     scan_data_t data;
     RExC_state_t RExC_state;
     RExC_state_t * const pRExC_state = &RExC_state;
 #ifdef TRIE_STUDY_OPT    
-    int restudied= 0;
+    int restudied;
     RExC_state_t copyRExC_state;
 #endif    
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_RE_COMPILE;
+
     DEBUG_r(if (!PL_colorset) reginitcolors());
 
-    RExC_utf8 = RExC_orig_utf8 = pm_flags & RXf_UTF8;
+    RExC_utf8 = RExC_orig_utf8 = SvUTF8(pattern);
 
-    DEBUG_COMPILE_r({
-        SV *dsv= sv_newmortal();
-        RE_PV_QUOTED_DECL(s, RExC_utf8,
-            dsv, exp, plen, 60);
-        PerlIO_printf(Perl_debug_log, "%sCompiling REx%s %s\n",
-                      PL_colors[4],PL_colors[5],s);
-    });
 
-redo_first_pass:
+    /* Longjmp back to here if have to switch in midstream to utf8 */
+    if (! RExC_orig_utf8) {
+       JMPENV_PUSH(jump_ret);
+    }
+
+    if (jump_ret == 0) {    /* First time through */
+        exp = SvPV(pattern, plen);
+        xend = exp + plen;
+
+        DEBUG_COMPILE_r({
+            SV *dsv= sv_newmortal();
+            RE_PV_QUOTED_DECL(s, RExC_utf8,
+                dsv, exp, plen, 60);
+            PerlIO_printf(Perl_debug_log, "%sCompiling REx%s %s\n",
+                           PL_colors[4],PL_colors[5],s);
+        });
+    }
+    else {  /* longjumped back */
+        STRLEN len = plen;
+
+        /* If the cause for the longjmp was other than changing to utf8, pop
+         * our own setjmp, and longjmp to the correct handler */
+       if (jump_ret != UTF8_LONGJMP) {
+           JMPENV_POP;
+           JMPENV_JUMP(jump_ret);
+       }
+
+       GET_RE_DEBUG_FLAGS;
+
+        /* It's possible to write a regexp in ascii that represents Unicode
+        codepoints outside of the byte range, such as via \x{100}. If we
+        detect such a sequence we have to convert the entire pattern to utf8
+        and then recompile, as our sizing calculation will have been based
+        on 1 byte == 1 character, but we will need to use utf8 to encode
+        at least some part of the pattern, and therefore must convert the whole
+        thing.
+        -- dmq */
+        DEBUG_PARSE_r(PerlIO_printf(Perl_debug_log,
+           "UTF8 mismatch! Converting to utf8 for resizing and compile\n"));
+        exp = (char*)Perl_bytes_to_utf8(aTHX_ (U8*)SvPV(pattern, plen), &len);
+        xend = exp + len;
+        RExC_orig_utf8 = RExC_utf8 = 1;
+        SAVEFREEPV(exp);
+    }
+
+#ifdef TRIE_STUDY_OPT
+    restudied = 0;
+#endif
+
     RExC_precomp = exp;
     RExC_flags = pm_flags;
     RExC_sawback = 0;
@@ -4205,7 +4429,6 @@ redo_first_pass:
     RExC_size = 0L;
     RExC_emit = &PL_regdummy;
     RExC_whilem_seen = 0;
-    RExC_charnames = NULL;
     RExC_open_parens = NULL;
     RExC_close_parens = NULL;
     RExC_opend = NULL;
@@ -4225,24 +4448,14 @@ redo_first_pass:
        RExC_precomp = NULL;
        return(NULL);
     }
-    if (RExC_utf8 && !RExC_orig_utf8) {
-        /* It's possible to write a regexp in ascii that represents Unicode
-        codepoints outside of the byte range, such as via \x{100}. If we
-        detect such a sequence we have to convert the entire pattern to utf8
-        and then recompile, as our sizing calculation will have been based
-        on 1 byte == 1 character, but we will need to use utf8 to encode
-        at least some part of the pattern, and therefore must convert the whole
-        thing.
-        XXX: somehow figure out how to make this less expensive...
-        -- dmq */
-        STRLEN len = plen;
-        DEBUG_PARSE_r(PerlIO_printf(Perl_debug_log,
-           "UTF8 mismatch! Converting to utf8 for resizing and compile\n"));
-        exp = (char*)Perl_bytes_to_utf8(aTHX_ (U8*)exp, &len);
-        xend = exp + len;
-        RExC_orig_utf8 = RExC_utf8;
-        SAVEFREEPV(exp);
-        goto redo_first_pass;
+
+    /* Here, finished first pass.  Get rid of our setjmp, which we added for
+     * efficiency only if the passed-in string wasn't in utf8, as shown by
+     * RExC_orig_utf8.  But if the first pass was redone, that variable will be
+     * 1 here even though the original string wasn't utf8, but in this case
+     * there will have been a long jump */
+    if (jump_ret == UTF8_LONGJMP || ! RExC_orig_utf8) {
+       JMPENV_POP;
     }
     DEBUG_PARSE_r({
         PerlIO_printf(Perl_debug_log, 
@@ -4264,7 +4477,8 @@ redo_first_pass:
     /* Allocate space and zero-initialize. Note, the two step process 
        of zeroing when in debug mode, thus anything assigned has to 
        happen after that */
-    Newxz(r, 1, regexp);
+    rx = (REGEXP*) newSV_type(SVt_REGEXP);
+    r = (struct regexp*)SvANY(rx);
     Newxc(ri, sizeof(regexp_internal) + (unsigned)RExC_size * sizeof(regnode),
         char, regexp_internal);
     if ( r == NULL || ri == NULL )
@@ -4280,52 +4494,71 @@ redo_first_pass:
     /* non-zero initialization begins here */
     RXi_SET( r, ri );
     r->engine= RE_ENGINE_PTR;
-    r->refcnt = 1;
     r->extflags = pm_flags;
     {
         bool has_p     = ((r->extflags & RXf_PMf_KEEPCOPY) == RXf_PMf_KEEPCOPY);
-       bool has_minus = ((r->extflags & RXf_PMf_STD_PMMOD) != RXf_PMf_STD_PMMOD);
+        bool has_charset = cBOOL(r->extflags & (RXf_PMf_LOCALE|RXf_PMf_UNICODE));
+
+        /* The caret is output if there are any defaults: if not all the STD
+         * flags are set, or if no character set specifier is needed */
+        bool has_default =
+                    (((r->extflags & RXf_PMf_STD_PMMOD) != RXf_PMf_STD_PMMOD)
+                    || ! has_charset);
        bool has_runon = ((RExC_seen & REG_SEEN_RUN_ON_COMMENT)==REG_SEEN_RUN_ON_COMMENT);
        U16 reganch = (U16)((r->extflags & RXf_PMf_STD_PMMOD)
                            >> RXf_PMf_STD_PMMOD_SHIFT);
        const char *fptr = STD_PAT_MODS;        /*"msix"*/
        char *p;
-        RX_WRAPLEN(r) = plen + has_minus + has_p + has_runon
+        /* Allocate for the worst case, which is all the std flags are turned
+         * on.  If more precision is desired, we could do a population count of
+         * the flags set.  This could be done with a small lookup table, or by
+         * shifting, masking and adding, or even, when available, assembly
+         * language for a machine-language population count.
+         * We never output a minus, as all those are defaults, so are
+         * covered by the caret */
+       const STRLEN wraplen = plen + has_p + has_runon
+            + has_default       /* If needs a caret */
+            + has_charset       /* If needs a character set specifier */
             + (sizeof(STD_PAT_MODS) - 1)
             + (sizeof("(?:)") - 1);
 
-        Newx(RX_WRAPPED(r), RX_WRAPLEN(r) + 1, char );
-        p = RX_WRAPPED(r);
+        p = sv_grow(MUTABLE_SV(rx), wraplen + 1); /* +1 for the ending NUL */
+       SvPOK_on(rx);
+       SvFLAGS(rx) |= SvUTF8(pattern);
         *p++='('; *p++='?';
+
+        /* If a default, cover it using the caret */
+        if (has_default) {
+            *p++= DEFAULT_PAT_MOD;
+        }
+        if (has_charset) {
+            if (r->extflags & RXf_PMf_LOCALE) {
+                *p++ = LOCALE_PAT_MOD;
+            } else {
+                *p++ = UNICODE_PAT_MOD;
+            }
+        }
         if (has_p)
             *p++ = KEEPCOPY_PAT_MOD; /*'p'*/
         {
-            char *r = p + (sizeof(STD_PAT_MODS) - 1) + has_minus - 1;
-            char *colon = r + 1;
             char ch;
-
             while((ch = *fptr++)) {
                 if(reganch & 1)
                     *p++ = ch;
-                else
-                    *r-- = ch;
                 reganch >>= 1;
             }
-            if(has_minus) {
-                *r = '-';
-                p = colon;
-            }
         }
 
         *p++ = ':';
         Copy(RExC_precomp, p, plen, char);
-       assert ((RX_WRAPPED(r) - p) < 16);
-       r->pre_prefix = p - RX_WRAPPED(r);
+       assert ((RX_WRAPPED(rx) - p) < 16);
+       r->pre_prefix = p - RX_WRAPPED(rx);
         p += plen;
         if (has_runon)
             *p++ = '\n';
         *p++ = ')';
         *p = 0;
+       SvCUR_set(rx, p - SvPVX_const(rx));
     }
 
     r->intflags = 0;
@@ -4347,6 +4580,7 @@ redo_first_pass:
                           (UV)((2*RExC_size+1) * sizeof(U32))));
 #endif
     SetProgLen(ri,RExC_size);
+    RExC_rx_sv = rx;
     RExC_rx = r;
     RExC_rxi = ri;
 
@@ -4364,7 +4598,7 @@ redo_first_pass:
     RExC_rx->seen_evals = RExC_seen_evals;
     REGC((U8)REG_MAGIC, (char*) RExC_emit++);
     if (reg(pRExC_state, 0, &flags,1) == NULL) {
-       ReREFCNT_dec(r);   
+       ReREFCNT_dec(rx);   
        return(NULL);
     }
     /* XXXX To minimize changes to RE engine we always allocate
@@ -4380,7 +4614,10 @@ reStudy:
     Zero(r->substrs, 1, struct reg_substr_data);
 
 #ifdef TRIE_STUDY_OPT
-    if ( restudied ) {
+    if (!restudied) {
+        StructCopy(&zero_scan_data, &data, scan_data_t);
+        copyRExC_state = RExC_state;
+    } else {
         U32 seen=RExC_seen;
         DEBUG_OPTIMISE_r(PerlIO_printf(Perl_debug_log,"Restudying\n"));
         
@@ -4395,9 +4632,6 @@ reStudy:
            SvREFCNT_dec(data.last_found);
        }
        StructCopy(&zero_scan_data, &data, scan_data_t);
-    } else {
-        StructCopy(&zero_scan_data, &data, scan_data_t);
-        copyRExC_state = RExC_state;
     }
 #else
     StructCopy(&zero_scan_data, &data, scan_data_t);
@@ -4408,7 +4642,7 @@ reStudy:
     /*dmq: removed as part of de-PMOP: pm->op_pmflags = RExC_flags; */
  
     if (UTF)
-        r->extflags |= RXf_UTF8;       /* Unicode in it? */
+       SvUTF8_on(rx);  /* Unicode in it? */
     ri->regstclass = NULL;
     if (RExC_naughty >= 10)    /* Probably an expensive pattern. */
        r->intflags |= PREGf_NAUGHTY;
@@ -4425,7 +4659,17 @@ reStudy:
         regnode *first= scan;
         regnode *first_next= regnext(first);
        
-       /* Skip introductions and multiplicators >= 1. */
+       /*
+        * Skip introductions and multiplicators >= 1
+        * so that we can extract the 'meat' of the pattern that must 
+        * match in the large if() sequence following.
+        * NOTE that EXACT is NOT covered here, as it is normally
+        * picked up by the optimiser separately. 
+        *
+        * This is unfortunate as the optimiser isnt handling lookahead
+        * properly currently.
+        *
+        */
        while ((OP(first) == OPEN && (sawopen = 1)) ||
               /* An OR of *one* alternative - should not happen now. */
            (OP(first) == BRANCH && OP(first_next) != BRANCH) ||
@@ -4437,16 +4681,17 @@ reStudy:
            (PL_regkind[OP(first)] == CURLY && ARG1(first) > 0) ||
            (OP(first) == NOTHING && PL_regkind[OP(first_next)] != END ))
        {
-               
+               /* 
+                * the only op that could be a regnode is PLUS, all the rest
+                * will be regnode_1 or regnode_2.
+                *
+                */
                if (OP(first) == PLUS)
                    sawplus = 1;
                else
                    first += regarglen[OP(first)];
-               if (OP(first) == IFMATCH) {
-                   first = NEXTOPER(first);
-                   first += EXTRA_STEP_2ARGS;
-               } else  /* XXX possible optimisation for /(?=)/  */
-                   first = NEXTOPER(first);
+               
+               first = NEXTOPER(first);
                first_next= regnext(first);
        }
 
@@ -4482,7 +4727,7 @@ reStudy:
            ri->regstclass = trie_op;
        }
 #endif 
-       else if (strchr((const char*)PL_simple,OP(first)))
+       else if (REGNODE_SIMPLE(OP(first)))
            ri->regstclass = first;
        else if (PL_regkind[OP(first)] == BOUND ||
                 PL_regkind[OP(first)] == NBOUND)
@@ -4790,22 +5035,22 @@ reStudy:
     if (RExC_seen & REG_SEEN_CUTGROUP)
        r->intflags |= PREGf_CUTGROUP_SEEN;
     if (RExC_paren_names)
-        r->paren_names = (HV*)SvREFCNT_inc(RExC_paren_names);
+        RXp_PAREN_NAMES(r) = MUTABLE_HV(SvREFCNT_inc(RExC_paren_names));
     else
-        r->paren_names = NULL;
+        RXp_PAREN_NAMES(r) = NULL;
 
 #ifdef STUPID_PATTERN_CHECKS            
-    if (RX_PRELEN(r) == 0)
+    if (RX_PRELEN(rx) == 0)
         r->extflags |= RXf_NULL;
-    if (r->extflags & RXf_SPLIT && RX_PRELEN(r) == 1 && RX_PRECOMP(r)[0] == ' ')
+    if (r->extflags & RXf_SPLIT && RX_PRELEN(rx) == 1 && RX_PRECOMP(rx)[0] == ' ')
         /* XXX: this should happen BEFORE we compile */
         r->extflags |= (RXf_SKIPWHITE|RXf_WHITE); 
-    else if (RX_PRELEN(r) == 3 && memEQ("\\s+", RX_PRECOMP(r), 3))
+    else if (RX_PRELEN(rx) == 3 && memEQ("\\s+", RX_PRECOMP(rx), 3))
         r->extflags |= RXf_WHITE;
-    else if (RX_PRELEN(r) == 1 && RX_PRECOMP(r)[0] == '^')
+    else if (RX_PRELEN(rx) == 1 && RXp_PRECOMP(rx)[0] == '^')
         r->extflags |= RXf_START_ONLY;
 #else
-    if (r->extflags & RXf_SPLIT && RX_PRELEN(r) == 1 && RX_PRECOMP(r)[0] == ' ')
+    if (r->extflags & RXf_SPLIT && RX_PRELEN(rx) == 1 && RX_PRECOMP(rx)[0] == ' ')
             /* XXX: this should happen BEFORE we compile */
             r->extflags |= (RXf_SKIPWHITE|RXf_WHITE); 
     else {
@@ -4823,7 +5068,7 @@ reStudy:
 #endif
 #ifdef DEBUGGING
     if (RExC_paren_names) {
-        ri->name_list_idx = add_data( pRExC_state, 1, "p" );
+        ri->name_list_idx = add_data( pRExC_state, 1, "a" );
         ri->data->data[ri->name_list_idx] = (void*)SvREFCNT_inc(RExC_paren_name_list);
     } else
 #endif
@@ -4856,7 +5101,7 @@ reStudy:
         PerlIO_printf(Perl_debug_log, "\n");
     });
 #endif
-    return(r);
+    return rx;
 }
 
 #undef RE_ENGINE_PTR
@@ -4866,12 +5111,14 @@ SV*
 Perl_reg_named_buff(pTHX_ REGEXP * const rx, SV * const key, SV * const value,
                     const U32 flags)
 {
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF;
+
     PERL_UNUSED_ARG(value);
 
     if (flags & RXapif_FETCH) {
         return reg_named_buff_fetch(rx, key, flags);
     } else if (flags & (RXapif_STORE | RXapif_DELETE | RXapif_CLEAR)) {
-        Perl_croak(aTHX_ PL_no_modify);
+        Perl_croak_no_modify(aTHX);
         return NULL;
     } else if (flags & RXapif_EXISTS) {
         return reg_named_buff_exists(rx, key, flags)
@@ -4891,6 +5138,7 @@ SV*
 Perl_reg_named_buff_iter(pTHX_ REGEXP * const rx, const SV * const lastkey,
                          const U32 flags)
 {
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_ITER;
     PERL_UNUSED_ARG(lastkey);
 
     if (flags & RXapif_FIRSTKEY)
@@ -4904,15 +5152,20 @@ Perl_reg_named_buff_iter(pTHX_ REGEXP * const rx, const SV * const lastkey,
 }
 
 SV*
-Perl_reg_named_buff_fetch(pTHX_ REGEXP * const rx, SV * const namesv, const U32 flags)
+Perl_reg_named_buff_fetch(pTHX_ REGEXP * const r, SV * const namesv,
+                         const U32 flags)
 {
     AV *retarray = NULL;
     SV *ret;
+    struct regexp *const rx = (struct regexp *)SvANY(r);
+
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_FETCH;
+
     if (flags & RXapif_ALL)
         retarray=newAV();
 
-    if (rx && rx->paren_names) {
-        HE *he_str = hv_fetch_ent( rx->paren_names, namesv, 0, 0 );
+    if (rx && RXp_PAREN_NAMES(rx)) {
+        HE *he_str = hv_fetch_ent( RXp_PAREN_NAMES(rx), namesv, 0, 0 );
         if (he_str) {
             IV i;
             SV* sv_dat=HeVAL(he_str);
@@ -4923,33 +5176,35 @@ Perl_reg_named_buff_fetch(pTHX_ REGEXP * const rx, SV * const namesv, const U32
                     && rx->offs[nums[i]].end != -1)
                 {
                     ret = newSVpvs("");
-                    CALLREG_NUMBUF_FETCH(rx,nums[i],ret);
+                    CALLREG_NUMBUF_FETCH(r,nums[i],ret);
                     if (!retarray)
                         return ret;
                 } else {
                     ret = newSVsv(&PL_sv_undef);
                 }
-                if (retarray) {
-                    SvREFCNT_inc_simple_void(ret);
+                if (retarray)
                     av_push(retarray, ret);
-                }
             }
             if (retarray)
-                return newRV((SV*)retarray);
+                return newRV_noinc(MUTABLE_SV(retarray));
         }
     }
     return NULL;
 }
 
 bool
-Perl_reg_named_buff_exists(pTHX_ REGEXP * const rx, SV * const key,
+Perl_reg_named_buff_exists(pTHX_ REGEXP * const r, SV * const key,
                            const U32 flags)
 {
-    if (rx && rx->paren_names) {
+    struct regexp *const rx = (struct regexp *)SvANY(r);
+
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_EXISTS;
+
+    if (rx && RXp_PAREN_NAMES(rx)) {
         if (flags & RXapif_ALL) {
-            return hv_exists_ent(rx->paren_names, key, 0);
+            return hv_exists_ent(RXp_PAREN_NAMES(rx), key, 0);
         } else {
-           SV *sv = CALLREG_NAMED_BUFF_FETCH(rx, key, flags);
+           SV *sv = CALLREG_NAMED_BUFF_FETCH(r, key, flags);
             if (sv) {
                SvREFCNT_dec(sv);
                 return TRUE;
@@ -4963,22 +5218,31 @@ Perl_reg_named_buff_exists(pTHX_ REGEXP * const rx, SV * const key,
 }
 
 SV*
-Perl_reg_named_buff_firstkey(pTHX_ REGEXP * const rx, const U32 flags)
+Perl_reg_named_buff_firstkey(pTHX_ REGEXP * const r, const U32 flags)
 {
-    if ( rx && rx->paren_names ) {
-       (void)hv_iterinit(rx->paren_names);
+    struct regexp *const rx = (struct regexp *)SvANY(r);
+
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_FIRSTKEY;
+
+    if ( rx && RXp_PAREN_NAMES(rx) ) {
+       (void)hv_iterinit(RXp_PAREN_NAMES(rx));
 
-       return CALLREG_NAMED_BUFF_NEXTKEY(rx, NULL, flags & ~RXapif_FIRSTKEY);
+       return CALLREG_NAMED_BUFF_NEXTKEY(r, NULL, flags & ~RXapif_FIRSTKEY);
     } else {
        return FALSE;
     }
 }
 
 SV*
-Perl_reg_named_buff_nextkey(pTHX_ REGEXP * const rx, const U32 flags)
+Perl_reg_named_buff_nextkey(pTHX_ REGEXP * const r, const U32 flags)
 {
-    if (rx && rx->paren_names) {
-        HV *hv = rx->paren_names;
+    struct regexp *const rx = (struct regexp *)SvANY(r);
+    GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_NEXTKEY;
+
+    if (rx && RXp_PAREN_NAMES(rx)) {
+        HV *hv = RXp_PAREN_NAMES(rx);
         HE *temphe;
         while ( (temphe = hv_iternext_flags(hv,0)) ) {
             IV i;
@@ -4986,7 +5250,7 @@ Perl_reg_named_buff_nextkey(pTHX_ REGEXP * const rx, const U32 flags)
             SV* sv_dat = HeVAL(temphe);
             I32 *nums = (I32*)SvPVX(sv_dat);
             for ( i = 0; i < SvIVX(sv_dat); i++ ) {
-                if ((I32)(rx->lastcloseparen) >= nums[i] &&
+                if ((I32)(rx->lastparen) >= nums[i] &&
                     rx->offs[nums[i]].start != -1 &&
                     rx->offs[nums[i]].end != -1)
                 {
@@ -4995,9 +5259,7 @@ Perl_reg_named_buff_nextkey(pTHX_ REGEXP * const rx, const U32 flags)
                 }
             }
             if (parno || flags & RXapif_ALL) {
-                STRLEN len;
-                char *pv = HePV(temphe, len);
-                return newSVpvn(pv,len);
+               return newSVhek(HeKEY_hek(temphe));
             }
         }
     }
@@ -5005,19 +5267,23 @@ Perl_reg_named_buff_nextkey(pTHX_ REGEXP * const rx, const U32 flags)
 }
 
 SV*
-Perl_reg_named_buff_scalar(pTHX_ REGEXP * const rx, const U32 flags)
+Perl_reg_named_buff_scalar(pTHX_ REGEXP * const r, const U32 flags)
 {
     SV *ret;
     AV *av;
     I32 length;
+    struct regexp *const rx = (struct regexp *)SvANY(r);
+
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_SCALAR;
 
-    if (rx && rx->paren_names) {
+    if (rx && RXp_PAREN_NAMES(rx)) {
         if (flags & (RXapif_ALL | RXapif_REGNAMES_COUNT)) {
-            return newSViv(HvTOTALKEYS(rx->paren_names));
+            return newSViv(HvTOTALKEYS(RXp_PAREN_NAMES(rx)));
         } else if (flags & RXapif_ONE) {
-            ret = CALLREG_NAMED_BUFF_ALL(rx, (flags | RXapif_REGNAMES));
-            av = (AV*)SvRV(ret);
+            ret = CALLREG_NAMED_BUFF_ALL(r, (flags | RXapif_REGNAMES));
+            av = MUTABLE_AV(SvRV(ret));
             length = av_len(av);
+           SvREFCNT_dec(ret);
             return newSViv(length + 1);
         } else {
             Perl_croak(aTHX_ "panic: Unknown flags %d in named_buff_scalar", (int)flags);
@@ -5028,12 +5294,15 @@ Perl_reg_named_buff_scalar(pTHX_ REGEXP * const rx, const U32 flags)
 }
 
 SV*
-Perl_reg_named_buff_all(pTHX_ REGEXP * const rx, const U32 flags)
+Perl_reg_named_buff_all(pTHX_ REGEXP * const r, const U32 flags)
 {
+    struct regexp *const rx = (struct regexp *)SvANY(r);
     AV *av = newAV();
 
-    if (rx && rx->paren_names) {
-        HV *hv= rx->paren_names;
+    PERL_ARGS_ASSERT_REG_NAMED_BUFF_ALL;
+
+    if (rx && RXp_PAREN_NAMES(rx)) {
+        HV *hv= RXp_PAREN_NAMES(rx);
         HE *temphe;
         (void)hv_iterinit(hv);
         while ( (temphe = hv_iternext_flags(hv,0)) ) {
@@ -5042,7 +5311,7 @@ Perl_reg_named_buff_all(pTHX_ REGEXP * const rx, const U32 flags)
             SV* sv_dat = HeVAL(temphe);
             I32 *nums = (I32*)SvPVX(sv_dat);
             for ( i = 0; i < SvIVX(sv_dat); i++ ) {
-                if ((I32)(rx->lastcloseparen) >= nums[i] &&
+                if ((I32)(rx->lastparen) >= nums[i] &&
                     rx->offs[nums[i]].start != -1 &&
                     rx->offs[nums[i]].end != -1)
                 {
@@ -5051,22 +5320,24 @@ Perl_reg_named_buff_all(pTHX_ REGEXP * const rx, const U32 flags)
                 }
             }
             if (parno || flags & RXapif_ALL) {
-                STRLEN len;
-                char *pv = HePV(temphe, len);
-                av_push(av, newSVpvn(pv,len));
+                av_push(av, newSVhek(HeKEY_hek(temphe)));
             }
         }
     }
 
-    return newRV((SV*)av);
+    return newRV_noinc(MUTABLE_SV(av));
 }
 
 void
-Perl_reg_numbered_buff_fetch(pTHX_ REGEXP * const rx, const I32 paren, SV * const sv)
+Perl_reg_numbered_buff_fetch(pTHX_ REGEXP * const r, const I32 paren,
+                            SV * const sv)
 {
+    struct regexp *const rx = (struct regexp *)SvANY(r);
     char *s = NULL;
     I32 i = 0;
     I32 s1, t1;
+
+    PERL_ARGS_ASSERT_REG_NUMBERED_BUFF_FETCH;
         
     if (!rx->subbeg) {
         sv_setsv(sv,&PL_sv_undef);
@@ -5103,16 +5374,16 @@ Perl_reg_numbered_buff_fetch(pTHX_ REGEXP * const rx, const I32 paren, SV * cons
         sv_setpvn(sv, s, i);
         PL_tainted = oldtainted;
         if ( (rx->extflags & RXf_CANY_SEEN)
-            ? (RX_MATCH_UTF8(rx)
+            ? (RXp_MATCH_UTF8(rx)
                         && (!i || is_utf8_string((U8*)s, i)))
-            : (RX_MATCH_UTF8(rx)) )
+            : (RXp_MATCH_UTF8(rx)) )
         {
             SvUTF8_on(sv);
         }
         else
             SvUTF8_off(sv);
         if (PL_tainting) {
-            if (RX_MATCH_TAINTED(rx)) {
+            if (RXp_MATCH_TAINTED(rx)) {
                 if (SvTYPE(sv) >= SVt_PVMG) {
                     MAGIC* const mg = SvMAGIC(sv);
                     MAGIC* mgt;
@@ -5140,21 +5411,26 @@ void
 Perl_reg_numbered_buff_store(pTHX_ REGEXP * const rx, const I32 paren,
                                                         SV const * const value)
 {
+    PERL_ARGS_ASSERT_REG_NUMBERED_BUFF_STORE;
+
     PERL_UNUSED_ARG(rx);
     PERL_UNUSED_ARG(paren);
     PERL_UNUSED_ARG(value);
 
     if (!PL_localizing)
-        Perl_croak(aTHX_ PL_no_modify);
+        Perl_croak_no_modify(aTHX);
 }
 
 I32
-Perl_reg_numbered_buff_length(pTHX_ REGEXP * const rx, const SV * const sv,
+Perl_reg_numbered_buff_length(pTHX_ REGEXP * const r, const SV * const sv,
                               const I32 paren)
 {
+    struct regexp *const rx = (struct regexp *)SvANY(r);
     I32 i;
     I32 s1, t1;
 
+    PERL_ARGS_ASSERT_REG_NUMBERED_BUFF_LENGTH;
+
     /* Some of this code was originally in C<Perl_magic_len> in F<mg.c> */
        switch (paren) {
       /* $` / ${^PREMATCH} */
@@ -5189,12 +5465,12 @@ Perl_reg_numbered_buff_length(pTHX_ REGEXP * const rx, const SV * const sv,
             goto getlen;
         } else {
             if (ckWARN(WARN_UNINITIALIZED))
-                report_uninit((SV*)sv);
+                report_uninit((const SV *)sv);
             return 0;
         }
     }
   getlen:
-    if (i > 0 && RX_MATCH_UTF8(rx)) {
+    if (i > 0 && RXp_MATCH_UTF8(rx)) {
         const char * const s = rx->subbeg + s1;
         const U8 *ep;
         STRLEN el;
@@ -5209,8 +5485,12 @@ Perl_reg_numbered_buff_length(pTHX_ REGEXP * const rx, const SV * const sv,
 SV*
 Perl_reg_qr_package(pTHX_ REGEXP * const rx)
 {
+    PERL_ARGS_ASSERT_REG_QR_PACKAGE;
        PERL_UNUSED_ARG(rx);
-       return NULL;
+       if (0)
+           return NULL;
+       else
+           return newSVpvs("Regexp");
 }
 
 /* Scans the name of a named buffer from the pattern.
@@ -5226,9 +5506,12 @@ Perl_reg_qr_package(pTHX_ REGEXP * const rx)
 #define REG_RSN_RETURN_DATA    2
 
 STATIC SV*
-S_reg_scan_name(pTHX_ RExC_state_t *pRExC_state, U32 flags) {
+S_reg_scan_name(pTHX_ RExC_state_t *pRExC_state, U32 flags)
+{
     char *name_start = RExC_parse;
 
+    PERL_ARGS_ASSERT_REG_SCAN_NAME;
+
     if (isIDFIRST_lazy_if(RExC_parse, UTF)) {
         /* skip IDFIRST by using do...while */
        if (UTF)
@@ -5242,10 +5525,9 @@ S_reg_scan_name(pTHX_ RExC_state_t *pRExC_state, U32 flags) {
     }
 
     if ( flags ) {
-        SV* sv_name = sv_2mortal(Perl_newSVpvn(aTHX_ name_start,
-            (int)(RExC_parse - name_start)));
-       if (UTF)
-            SvUTF8_on(sv_name);
+        SV* sv_name
+           = newSVpvn_flags(name_start, (int)(RExC_parse - name_start),
+                            SVs_TEMP | (UTF ? SVf_UTF8 : 0));
         if ( flags == REG_RSN_RETURN_NAME)
             return sv_name;
         else if (flags==REG_RSN_RETURN_DATA) {
@@ -5360,6 +5642,8 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     char * const oregcomp_parse = RExC_parse;
 
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REG;
     DEBUG_PARSE("reg ");
 
     *flagp = 0;                                /* Tentatively. */
@@ -5475,6 +5759,7 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
        if (*RExC_parse == '?') { /* (?...) */
            bool is_logical = 0;
            const char * const seqstart = RExC_parse;
+            bool has_use_defaults = FALSE;
 
            RExC_parse++;
            paren = *RExC_parse++;
@@ -5549,10 +5834,10 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                                 "panic: reg_scan_name returned NULL");
                         if (!RExC_paren_names) {
                             RExC_paren_names= newHV();
-                            sv_2mortal((SV*)RExC_paren_names);
+                            sv_2mortal(MUTABLE_SV(RExC_paren_names));
 #ifdef DEBUGGING
                             RExC_paren_name_list= newAV();
-                            sv_2mortal((SV*)RExC_paren_name_list);
+                            sv_2mortal(MUTABLE_SV(RExC_paren_name_list));
 #endif
                         }
                         he_str = hv_fetch_ent( RExC_paren_names, svname, 1, 0 );
@@ -5581,13 +5866,13 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                                 pv = (I32*)SvGROW(sv_dat, SvCUR(sv_dat) + sizeof(I32)+1);
                                 SvCUR_set(sv_dat, SvCUR(sv_dat) + sizeof(I32));
                                 pv[count] = RExC_npar;
-                                SvIVX(sv_dat)++;
+                                SvIV_set(sv_dat, SvIVX(sv_dat) + 1);
                             }
                         } else {
                             (void)SvUPGRADE(sv_dat,SVt_PVNV);
                             sv_setpvn(sv_dat, (char *)&(RExC_npar), sizeof(I32));
                             SvIOK_on(sv_dat);
-                            SvIVX(sv_dat)= 1;
+                            SvIV_set(sv_dat, 1);
                         }
 #ifdef DEBUGGING
                         if (!av_store(RExC_paren_name_list, RExC_npar, SvREFCNT_inc(svname)))
@@ -5603,6 +5888,8 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                 RExC_seen |= REG_SEEN_LOOKBEHIND;
                RExC_parse++;
            case '=':           /* (?=...) */
+               RExC_seen_zerolen++;
+                break;
            case '!':           /* (?!...) */
                RExC_seen_zerolen++;
                if (*RExC_parse == ')') {
@@ -5927,12 +6214,19 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                RExC_parse--; /* for vFAIL to print correctly */
                 vFAIL("Sequence (? incomplete");
                 break;
+            case DEFAULT_PAT_MOD:   /* Use default flags with the exceptions
+                                      that follow */
+                has_use_defaults = TRUE;
+                STD_PMMOD_FLAGS_CLEAR(&RExC_flags);
+                RExC_flags &= ~(RXf_PMf_LOCALE|RXf_PMf_UNICODE);
+                goto parse_flags;
            default:
                --RExC_parse;
                parse_flags:      /* (?i) */  
            {
                 U32 posflags = 0, negflags = 0;
                U32 *flagsp = &posflags;
+                bool has_charset_modifier = 0;
 
                while (*RExC_parse) {
                    /* && strchr("iogcmsx", *RExC_parse) */
@@ -5940,6 +6234,32 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                       and must be globally applied -- japhy */
                     switch (*RExC_parse) {
                    CASE_STD_PMMOD_FLAGS_PARSE_SET(flagsp);
+                    case LOCALE_PAT_MOD:
+                        if (has_charset_modifier || flagsp == &negflags) {
+                            goto fail_modifiers;
+                        }
+                        *flagsp &= ~RXf_PMf_UNICODE;
+                        *flagsp |= RXf_PMf_LOCALE;
+                        has_charset_modifier = 1;
+                        break;
+                    case UNICODE_PAT_MOD:
+                        if (has_charset_modifier || flagsp == &negflags) {
+                            goto fail_modifiers;
+                        }
+                        *flagsp &= ~RXf_PMf_LOCALE;
+                        *flagsp |= RXf_PMf_UNICODE;
+                        has_charset_modifier = 1;
+                        break;
+                    case DUAL_PAT_MOD:
+                        if (has_use_defaults
+                            || has_charset_modifier
+                            || flagsp == &negflags)
+                        {
+                            goto fail_modifiers;
+                        }
+                        *flagsp &= ~(RXf_PMf_LOCALE|RXf_PMf_UNICODE);
+                        has_charset_modifier = 1;
+                        break;
                     case ONCE_PAT_MOD: /* 'o' */
                     case GLOBAL_PAT_MOD: /* 'g' */
                        if (SIZE_ONLY && ckWARN(WARN_REGEXP)) {
@@ -5973,14 +6293,18 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                        break;
                    case KEEPCOPY_PAT_MOD: /* 'p' */
                         if (flagsp == &negflags) {
-                            if (SIZE_ONLY && ckWARN(WARN_REGEXP))
-                                vWARN(RExC_parse + 1,"Useless use of (?-p)");
+                            if (SIZE_ONLY)
+                                ckWARNreg(RExC_parse + 1,"Useless use of (?-p)");
                         } else {
                             *flagsp |= RXf_PMf_KEEPCOPY;
                         }
                        break;
                     case '-':
-                        if (flagsp == &negflags) {
+                        /* A flag is a default iff it is following a minus,  so
+                         * if there is a minus, it means will be trying to
+                         * re-specify a default which is an error */
+                        if (has_use_defaults || flagsp == &negflags) {
+            fail_modifiers:
                             RExC_parse++;
                            vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
                            /*NOTREACHED*/
@@ -6046,6 +6370,13 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     /* Pick up the branches, linking them together. */
     parse_start = RExC_parse;   /* MJD */
     br = regbranch(pRExC_state, &flags, 1,depth+1);
+
+    if (freeze_paren) {
+        if (RExC_npar > after_freeze)
+            after_freeze = RExC_npar;
+        RExC_npar = freeze_paren;
+    }
+
     /*     branch_len = (paren != 0); */
 
     if (br == NULL)
@@ -6204,6 +6535,9 @@ S_regbranch(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, I32 first, U32 depth)
     register regnode *latest;
     I32 flags = 0, c = 0;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGBRANCH;
+
     DEBUG_PARSE("brnc");
 
     if (first)
@@ -6279,6 +6613,9 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
     char *parse_start;
     const char *maxpos = NULL;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGPIECE;
+
     DEBUG_PARSE("piec");
 
     ret = regatom(pRExC_state, &flags,depth+1);
@@ -6356,7 +6693,7 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
                *flagp = WORST;
            if (max > 0)
                *flagp |= HASWIDTH;
-           if (max && max < min)
+           if (max < min)
                vFAIL("Can't do {n,m} with n > m");
            if (!SIZE_ONLY) {
                ARG1_SET(ret, (U16)min);
@@ -6416,11 +6753,11 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
        goto do_curly;
     }
   nest_check:
-    if (!SIZE_ONLY && !(flags&(HASWIDTH|POSTPONED)) && max > REG_INFTY/3 && ckWARN(WARN_REGEXP)) {
-       vWARN3(RExC_parse,
-              "%.*s matches null string many times",
-              (int)(RExC_parse >= origparse ? RExC_parse - origparse : 0),
-              origparse);
+    if (!SIZE_ONLY && !(flags&(HASWIDTH|POSTPONED)) && max > REG_INFTY/3) {
+       ckWARN3reg(RExC_parse,
+                  "%.*s matches null string many times",
+                  (int)(RExC_parse >= origparse ? RExC_parse - origparse : 0),
+                  origparse);
     }
 
     if (RExC_parse < RExC_end && *RExC_parse == '?') {
@@ -6455,271 +6792,276 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
 /* reg_namedseq(pRExC_state,UVp)
    
    This is expected to be called by a parser routine that has 
-   recognized'\N' and needs to handle the rest. RExC_parse is 
+   recognized '\N' and needs to handle the rest. RExC_parse is
    expected to point at the first char following the N at the time
    of the call.
+
+   The \N may be inside (indicated by valuep not being NULL) or outside a
+   character class.
+
+   \N may begin either a named sequence, or if outside a character class, mean
+   to match a non-newline.  For non single-quoted regexes, the tokenizer has
+   attempted to decide which, and in the case of a named sequence converted it
+   into one of the forms: \N{} (if the sequence is null), or \N{U+c1.c2...},
+   where c1... are the characters in the sequence.  For single-quoted regexes,
+   the tokenizer passes the \N sequence through unchanged; this code will not
+   attempt to determine this nor expand those.  The net effect is that if the
+   beginning of the passed-in pattern isn't '{U+' or there is no '}', it
+   signals that this \N occurrence means to match a non-newline.
+   
+   Only the \N{U+...} form should occur in a character class, for the same
+   reason that '.' inside a character class means to just match a period: it
+   just doesn't make sense.
    
    If valuep is non-null then it is assumed that we are parsing inside 
    of a charclass definition and the first codepoint in the resolved
    string is returned via *valuep and the routine will return NULL. 
    In this mode if a multichar string is returned from the charnames 
-   handler a warning will be issued, and only the first char in the 
+   handler, a warning will be issued, and only the first char in the 
    sequence will be examined. If the string returned is zero length
    then the value of *valuep is undefined and NON-NULL will 
    be returned to indicate failure. (This will NOT be a valid pointer 
    to a regnode.)
    
-   If value is null then it is assumed that we are parsing normal text
-   and inserts a new EXACT node into the program containing the resolved
-   string and returns a pointer to the new node. If the string is 
-   zerolength a NOTHING node is emitted.
-   
+   If valuep is null then it is assumed that we are parsing normal text and a
+   new EXACT node is inserted into the program containing the resolved string,
+   and a pointer to the new node is returned.  But if the string is zero length
+   a NOTHING node is emitted instead.
+
    On success RExC_parse is set to the char following the endbrace.
-   Parsing failures will generate a fatal errorvia vFAIL(...)
-   
-   NOTE: We cache all results from the charnames handler locally in 
-   the RExC_charnames hash (created on first use) to prevent a charnames 
-   handler from playing silly-buggers and returning a short string and 
-   then a long string for a given pattern. Since the regexp program 
-   size is calculated during an initial parse this would result
-   in a buffer overrun so we cache to prevent the charname result from
-   changing during the course of the parse.
-   
+   Parsing failures will generate a fatal error via vFAIL(...)
  */
 STATIC regnode *
-S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep
+S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep, I32 *flagp)
 {
-    char * name;        /* start of the content of the name */
-    char * endbrace;    /* endbrace following the name */
-    SV *sv_str = NULL;  
-    SV *sv_name = NULL;
-    STRLEN len; /* this has various purposes throughout the code */
-    bool cached = 0; /* if this is true then we shouldn't refcount dev sv_str */
+    char * endbrace;    /* '}' following the name */
     regnode *ret = NULL;
-    
+#ifdef DEBUGGING
+    char* parse_start = RExC_parse - 2;            /* points to the '\N' */
+#endif
+    char* p;
+
+    GET_RE_DEBUG_FLAGS_DECL;
+    PERL_ARGS_ASSERT_REG_NAMEDSEQ;
+
+    GET_RE_DEBUG_FLAGS;
+
+    /* The [^\n] meaning of \N ignores spaces and comments under the /x
+     * modifier.  The other meaning does not */
+    p = (RExC_flags & RXf_PMf_EXTENDED)
+       ? regwhite( pRExC_state, RExC_parse )
+       : RExC_parse;
+   
+    /* Disambiguate between \N meaning a named character versus \N meaning
+     * [^\n].  The former is assumed when it can't be the latter. */
+    if (*p != '{' || regcurly(p)) {
+       RExC_parse = p;
+       if (valuep) {
+           /* no bare \N in a charclass */
+           vFAIL("\\N in a character class must be a named character: \\N{...}");
+       }
+       nextchar(pRExC_state);
+       ret = reg_node(pRExC_state, REG_ANY);
+       *flagp |= HASWIDTH|SIMPLE;
+       RExC_naughty++;
+       RExC_parse--;
+        Set_Node_Length(ret, 1); /* MJD */
+       return ret;
+    }
+
+    /* Here, we have decided it should be a named sequence */
+
+    /* The test above made sure that the next real character is a '{', but
+     * under the /x modifier, it could be separated by space (or a comment and
+     * \n) and this is not allowed (for consistency with \x{...} and the
+     * tokenizer handling of \N{NAME}). */
     if (*RExC_parse != '{') {
-        vFAIL("Missing braces on \\N{}");
+       vFAIL("Missing braces on \\N{}");
     }
-    name = RExC_parse+1;
-    endbrace = strchr(RExC_parse, '}');
-    if ( ! endbrace ) {
-        RExC_parse++;
-        vFAIL("Missing right brace on \\N{}");
-    } 
-    RExC_parse = endbrace + 1;  
-    
-    
-    /* RExC_parse points at the beginning brace, 
-       endbrace points at the last */
-    if ( name[0]=='U' && name[1]=='+' ) {
-        /* its a "Unicode hex" notation {U+89AB} */
-        I32 fl = PERL_SCAN_ALLOW_UNDERSCORES
-            | PERL_SCAN_DISALLOW_PREFIX
-            | (SIZE_ONLY ? PERL_SCAN_SILENT_ILLDIGIT : 0);
-        UV cp;
-       char string;
-        len = (STRLEN)(endbrace - name - 2);
-        cp = grok_hex(name + 2, &len, &fl, NULL);
-        if ( len != (STRLEN)(endbrace - name - 2) ) {
-            cp = 0xFFFD;
-        }    
-        if (cp > 0xff)
-            RExC_utf8 = 1;
-        if ( valuep ) {
-            *valuep = cp;
-            return NULL;
-        }
-       string = (char)cp;
-        sv_str= newSVpvn(&string, 1);
-    } else {
-        /* fetch the charnames handler for this scope */
-        HV * const table = GvHV(PL_hintgv);
-        SV **cvp= table ? 
-            hv_fetchs(table, "charnames", FALSE) :
-            NULL;
-        SV *cv= cvp ? *cvp : NULL;
-        HE *he_str;
-        int count;
-        /* create an SV with the name as argument */
-        sv_name = newSVpvn(name, endbrace - name);
-        
-        if (!table || !(PL_hints & HINT_LOCALIZE_HH)) {
-            vFAIL2("Constant(\\N{%s}) unknown: "
-                  "(possibly a missing \"use charnames ...\")",
-                  SvPVX(sv_name));
-        }
-        if (!cvp || !SvOK(*cvp)) { /* when $^H{charnames} = undef; */
-            vFAIL2("Constant(\\N{%s}): "
-                  "$^H{charnames} is not defined",SvPVX(sv_name));
-        }
-        
-        
-        
-        if (!RExC_charnames) {
-            /* make sure our cache is allocated */
-            RExC_charnames = newHV();
-            sv_2mortal((SV*)RExC_charnames);
-        } 
-            /* see if we have looked this one up before */
-        he_str = hv_fetch_ent( RExC_charnames, sv_name, 0, 0 );
-        if ( he_str ) {
-            sv_str = HeVAL(he_str);
-            cached = 1;
-        } else {
-            dSP ;
 
-            ENTER ;
-            SAVETMPS ;
-            PUSHMARK(SP) ;
-            
-            XPUSHs(sv_name);
-            
-            PUTBACK ;
-            
-            count= call_sv(cv, G_SCALAR);
-            
-            if (count == 1) { /* XXXX is this right? dmq */
-                sv_str = POPs;
-                SvREFCNT_inc_simple_void(sv_str);
-            } 
-            
-            SPAGAIN ;
-            PUTBACK ;
-            FREETMPS ;
-            LEAVE ;
-            
-            if ( !sv_str || !SvOK(sv_str) ) {
-                vFAIL2("Constant(\\N{%s}): Call to &{$^H{charnames}} "
-                      "did not return a defined value",SvPVX(sv_name));
-            }
-            if (hv_store_ent( RExC_charnames, sv_name, sv_str, 0))
-                cached = 1;
-        }
+    RExC_parse++;      /* Skip past the '{' */
+
+    if (! (endbrace = strchr(RExC_parse, '}')) /* no trailing brace */
+       || ! (endbrace == RExC_parse            /* nothing between the {} */
+             || (endbrace - RExC_parse >= 2    /* U+ (bad hex is checked below */
+                 && strnEQ(RExC_parse, "U+", 2)))) /* for a better error msg) */
+    {
+       if (endbrace) RExC_parse = endbrace;    /* position msg's '<--HERE' */
+       vFAIL("\\N{NAME} must be resolved by the lexer");
     }
-    if (valuep) {
-        char *p = SvPV(sv_str, len);
-        if (len) {
-            STRLEN numlen = 1;
-            if ( SvUTF8(sv_str) ) {
-                *valuep = utf8_to_uvchr((U8*)p, &numlen);
-                if (*valuep > 0x7F)
-                    RExC_utf8 = 1; 
-                /* XXXX
-                  We have to turn on utf8 for high bit chars otherwise
-                  we get failures with
-                  
-                   "ss" =~ /[\N{LATIN SMALL LETTER SHARP S}]/i
-                   "SS" =~ /[\N{LATIN SMALL LETTER SHARP S}]/i
-                
-                  This is different from what \x{} would do with the same
-                  codepoint, where the condition is > 0xFF.
-                  - dmq
-                */
-                
-                
-            } else {
-                *valuep = (UV)*p;
-                /* warn if we havent used the whole string? */
-            }
-            if (numlen<len && SIZE_ONLY && ckWARN(WARN_REGEXP)) {
-                vWARN2(RExC_parse,
-                    "Ignoring excess chars from \\N{%s} in character class",
-                    SvPVX(sv_name)
-                );
-            }        
-        } else if (SIZE_ONLY && ckWARN(WARN_REGEXP)) {
-            vWARN2(RExC_parse,
-                    "Ignoring zero length \\N{%s} in character class",
-                    SvPVX(sv_name)
-                );
-        }
-        if (sv_name)    
-            SvREFCNT_dec(sv_name);    
-        if (!cached)
-            SvREFCNT_dec(sv_str);    
-        return len ? NULL : (regnode *)&len;
-    } else if(SvCUR(sv_str)) {     
-        
-        char *s; 
-        char *p, *pend;        
-        STRLEN charlen = 1;
-#ifdef DEBUGGING
-        char * parse_start = name-3; /* needed for the offsets */
-#endif
-        GET_RE_DEBUG_FLAGS_DECL;     /* needed for the offsets */
-        
-        ret = reg_node(pRExC_state,
-            (U8)(FOLD ? (LOC ? EXACTFL : EXACTF) : EXACT));
-        s= STRING(ret);
-        
-        if ( RExC_utf8 && !SvUTF8(sv_str) ) {
-            sv_utf8_upgrade(sv_str);
-        } else if ( !RExC_utf8 && SvUTF8(sv_str) ) {
-            RExC_utf8= 1;
-        }
-        
-        p = SvPV(sv_str, len);
-        pend = p + len;
-        /* len is the length written, charlen is the size the char read */
-        for ( len = 0; p < pend; p += charlen ) {
-            if (UTF) {
-                UV uvc = utf8_to_uvchr((U8*)p, &charlen);
-                if (FOLD) {
-                    STRLEN foldlen,numlen;
-                    U8 tmpbuf[UTF8_MAXBYTES_CASE+1], *foldbuf;
-                    uvc = toFOLD_uni(uvc, tmpbuf, &foldlen);
-                    /* Emit all the Unicode characters. */
-                    
-                    for (foldbuf = tmpbuf;
-                        foldlen;
-                        foldlen -= numlen) 
-                    {
-                        uvc = utf8_to_uvchr(foldbuf, &numlen);
-                        if (numlen > 0) {
-                            const STRLEN unilen = reguni(pRExC_state, uvc, s);
-                            s       += unilen;
-                            len     += unilen;
-                            /* In EBCDIC the numlen
-                            * and unilen can differ. */
-                            foldbuf += numlen;
-                            if (numlen >= foldlen)
-                                break;
-                        }
-                        else
-                            break; /* "Can't happen." */
-                    }                          
-                } else {
-                    const STRLEN unilen = reguni(pRExC_state, uvc, s);
-                   if (unilen > 0) {
-                      s   += unilen;
-                      len += unilen;
-                   }
-               }
-           } else {
-                len++;
-                REGC(*p, s++);
-            }
-        }
-        if (SIZE_ONLY) {
-            RExC_size += STR_SZ(len);
-        } else {
-            STR_LEN(ret) = len;
-            RExC_emit += STR_SZ(len);
-        }
-        Set_Node_Cur_Length(ret); /* MJD */
-        RExC_parse--; 
-        nextchar(pRExC_state);
-    } else {
-        ret = reg_node(pRExC_state,NOTHING);
+
+    if (endbrace == RExC_parse) {   /* empty: \N{} */
+       if (! valuep) {
+           RExC_parse = endbrace + 1;  
+           return reg_node(pRExC_state,NOTHING);
+       }
+
+       if (SIZE_ONLY) {
+           ckWARNreg(RExC_parse,
+                   "Ignoring zero length \\N{} in character class"
+           );
+           RExC_parse = endbrace + 1;  
+       }
+       *valuep = 0;
+       return (regnode *) &RExC_parse; /* Invalid regnode pointer */
     }
-    if (!cached) {
-        SvREFCNT_dec(sv_str);
+
+    REQUIRE_UTF8;      /* named sequences imply Unicode semantics */
+    RExC_parse += 2;   /* Skip past the 'U+' */
+
+    if (valuep) {   /* In a bracketed char class */
+       /* We only pay attention to the first char of 
+       multichar strings being returned. I kinda wonder
+       if this makes sense as it does change the behaviour
+       from earlier versions, OTOH that behaviour was broken
+       as well. XXX Solution is to recharacterize as
+       [rest-of-class]|multi1|multi2... */
+
+       STRLEN length_of_hex;
+       I32 flags = PERL_SCAN_ALLOW_UNDERSCORES
+           | PERL_SCAN_DISALLOW_PREFIX
+           | (SIZE_ONLY ? PERL_SCAN_SILENT_ILLDIGIT : 0);
+    
+       char * endchar = RExC_parse + strcspn(RExC_parse, ".}");
+       if (endchar < endbrace) {
+           ckWARNreg(endchar, "Using just the first character returned by \\N{} in character class");
+       }
+
+       length_of_hex = (STRLEN)(endchar - RExC_parse);
+       *valuep = grok_hex(RExC_parse, &length_of_hex, &flags, NULL);
+
+       /* The tokenizer should have guaranteed validity, but it's possible to
+        * bypass it by using single quoting, so check */
+       if (length_of_hex == 0
+           || length_of_hex != (STRLEN)(endchar - RExC_parse) )
+       {
+           RExC_parse += length_of_hex;        /* Includes all the valid */
+           RExC_parse += (RExC_orig_utf8)      /* point to after 1st invalid */
+                           ? UTF8SKIP(RExC_parse)
+                           : 1;
+           /* Guard against malformed utf8 */
+           if (RExC_parse >= endchar) RExC_parse = endchar;
+           vFAIL("Invalid hexadecimal number in \\N{U+...}");
+       }    
+
+       RExC_parse = endbrace + 1;
+       if (endchar == endbrace) return NULL;
+
+        ret = (regnode *) &RExC_parse; /* Invalid regnode pointer */
     }
-    if (sv_name) {
-        SvREFCNT_dec(sv_name); 
+    else {     /* Not a char class */
+       char *s;            /* String to put in generated EXACT node */
+       STRLEN len = 0;     /* Its current byte length */
+       char *endchar;      /* Points to '.' or '}' ending cur char in the input
+                              stream */
+
+       ret = reg_node(pRExC_state,
+                       (U8)(FOLD ? (LOC ? EXACTFL : EXACTF) : EXACT));
+       s= STRING(ret);
+
+       /* Exact nodes can hold only a U8 length's of text = 255.  Loop through
+        * the input which is of the form now 'c1.c2.c3...}' until find the
+        * ending brace or exceed length 255.  The characters that exceed this
+        * limit are dropped.  The limit could be relaxed should it become
+        * desirable by reparsing this as (?:\N{NAME}), so could generate
+        * multiple EXACT nodes, as is done for just regular input.  But this
+        * is primarily a named character, and not intended to be a huge long
+        * string, so 255 bytes should be good enough */
+       while (1) {
+           STRLEN length_of_hex;
+           I32 grok_flags = PERL_SCAN_ALLOW_UNDERSCORES
+                           | PERL_SCAN_DISALLOW_PREFIX
+                           | (SIZE_ONLY ? PERL_SCAN_SILENT_ILLDIGIT : 0);
+           UV cp;  /* Ord of current character */
+
+           /* Code points are separated by dots.  If none, there is only one
+            * code point, and is terminated by the brace */
+           endchar = RExC_parse + strcspn(RExC_parse, ".}");
+
+           /* The values are Unicode even on EBCDIC machines */
+           length_of_hex = (STRLEN)(endchar - RExC_parse);
+           cp = grok_hex(RExC_parse, &length_of_hex, &grok_flags, NULL);
+           if ( length_of_hex == 0 
+               || length_of_hex != (STRLEN)(endchar - RExC_parse) )
+           {
+               RExC_parse += length_of_hex;        /* Includes all the valid */
+               RExC_parse += (RExC_orig_utf8)  /* point to after 1st invalid */
+                               ? UTF8SKIP(RExC_parse)
+                               : 1;
+               /* Guard against malformed utf8 */
+               if (RExC_parse >= endchar) RExC_parse = endchar;
+               vFAIL("Invalid hexadecimal number in \\N{U+...}");
+           }    
+
+           if (! FOLD) {       /* Not folding, just append to the string */
+               STRLEN unilen;
+
+               /* Quit before adding this character if would exceed limit */
+               if (len + UNISKIP(cp) > U8_MAX) break;
+
+               unilen = reguni(pRExC_state, cp, s);
+               if (unilen > 0) {
+                   s   += unilen;
+                   len += unilen;
+               }
+           } else {    /* Folding, output the folded equivalent */
+               STRLEN foldlen,numlen;
+               U8 tmpbuf[UTF8_MAXBYTES_CASE+1], *foldbuf;
+               cp = toFOLD_uni(cp, tmpbuf, &foldlen);
+
+               /* Quit before exceeding size limit */
+               if (len + foldlen > U8_MAX) break;
+               
+               for (foldbuf = tmpbuf;
+                   foldlen;
+                   foldlen -= numlen) 
+               {
+                   cp = utf8_to_uvchr(foldbuf, &numlen);
+                   if (numlen > 0) {
+                       const STRLEN unilen = reguni(pRExC_state, cp, s);
+                       s       += unilen;
+                       len     += unilen;
+                       /* In EBCDIC the numlen and unilen can differ. */
+                       foldbuf += numlen;
+                       if (numlen >= foldlen)
+                           break;
+                   }
+                   else
+                       break; /* "Can't happen." */
+               }                          
+           }
+
+           /* Point to the beginning of the next character in the sequence. */
+           RExC_parse = endchar + 1;
+
+           /* Quit if no more characters */
+           if (RExC_parse >= endbrace) break;
+       }
+
+
+       if (SIZE_ONLY) {
+           if (RExC_parse < endbrace) {
+               ckWARNreg(RExC_parse - 1,
+                         "Using just the first characters returned by \\N{}");
+           }
+
+           RExC_size += STR_SZ(len);
+       } else {
+           STR_LEN(ret) = len;
+           RExC_emit += STR_SZ(len);
+       }
+
+       RExC_parse = endbrace + 1;
+
+       *flagp |= HASWIDTH; /* Not SIMPLE, as that causes the engine to fail
+                              with malformed in t/re/pat_advanced.t */
+       RExC_parse --;
+       Set_Node_Cur_Length(ret); /* MJD */
+       nextchar(pRExC_state);
     }
-    return ret;
 
+    return ret;
 }
 
 
@@ -6737,11 +7079,13 @@ STATIC UV
 S_reg_recode(pTHX_ const char value, SV **encp)
 {
     STRLEN numlen = 1;
-    SV * const sv = sv_2mortal(newSVpvn(&value, numlen));
+    SV * const sv = newSVpvn_flags(&value, numlen, SVs_TEMP);
     const char * const s = *encp ? sv_recode_to_utf8(sv, *encp) : SvPVX(sv);
     const STRLEN newlen = SvCUR(sv);
     UV uv = UNICODE_REPLACEMENT;
 
+    PERL_ARGS_ASSERT_REG_RECODE;
+
     if (newlen)
        uv = SvUTF8(sv)
             ? utf8n_to_uvchr((U8*)s, newlen, &numlen, UTF8_ALLOW_DEFAULT)
@@ -6788,6 +7132,7 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
     DEBUG_PARSE("atom");
     *flagp = WORST;            /* Tentatively. */
 
+    PERL_ARGS_ASSERT_REGATOM;
 
 tryagain:
     switch ((U8)*RExC_parse) {
@@ -6950,31 +7295,61 @@ tryagain:
            *flagp |= HASWIDTH;
            goto finish_meta_pat;
        case 'w':
-           ret = reg_node(pRExC_state, (U8)(LOC ? ALNUML     : ALNUM));
+           if (LOC) {
+                ret = reg_node(pRExC_state, (U8)(ALNUML));
+            } else {
+                ret = reg_node(pRExC_state, (U8)(ALNUM));
+                FLAGS(ret) = (UNI_SEMANTICS) ? USE_UNI : 0;
+            }
            *flagp |= HASWIDTH|SIMPLE;
            goto finish_meta_pat;
        case 'W':
-           ret = reg_node(pRExC_state, (U8)(LOC ? NALNUML    : NALNUM));
+            if (LOC) {
+                ret = reg_node(pRExC_state, (U8)(NALNUML));
+            } else {
+                ret = reg_node(pRExC_state, (U8)(NALNUM));
+                FLAGS(ret) = (UNI_SEMANTICS) ? USE_UNI : 0;
+            }
            *flagp |= HASWIDTH|SIMPLE;
            goto finish_meta_pat;
        case 'b':
            RExC_seen_zerolen++;
            RExC_seen |= REG_SEEN_LOOKBEHIND;
-           ret = reg_node(pRExC_state, (U8)(LOC ? BOUNDL     : BOUND));
+            if (LOC) {
+                ret = reg_node(pRExC_state, (U8)(BOUNDL));
+            } else {
+                ret = reg_node(pRExC_state, (U8)(BOUND));
+                FLAGS(ret) = (UNI_SEMANTICS) ? USE_UNI : 0;
+            }
            *flagp |= SIMPLE;
            goto finish_meta_pat;
        case 'B':
            RExC_seen_zerolen++;
            RExC_seen |= REG_SEEN_LOOKBEHIND;
-           ret = reg_node(pRExC_state, (U8)(LOC ? NBOUNDL    : NBOUND));
+            if (LOC) {
+                ret = reg_node(pRExC_state, (U8)(NBOUNDL));
+            } else {
+                ret = reg_node(pRExC_state, (U8)(NBOUND));
+                FLAGS(ret) = (UNI_SEMANTICS) ? USE_UNI : 0;
+            }
            *flagp |= SIMPLE;
            goto finish_meta_pat;
        case 's':
-           ret = reg_node(pRExC_state, (U8)(LOC ? SPACEL     : SPACE));
+            if (LOC) {
+                ret = reg_node(pRExC_state, (U8)(SPACEL));
+            } else {
+                ret = reg_node(pRExC_state, (U8)(SPACE));
+                FLAGS(ret) = (UNI_SEMANTICS) ? USE_UNI : 0;
+            }
            *flagp |= HASWIDTH|SIMPLE;
            goto finish_meta_pat;
        case 'S':
-           ret = reg_node(pRExC_state, (U8)(LOC ? NSPACEL    : NSPACE));
+            if (LOC) {
+                ret = reg_node(pRExC_state, (U8)(NSPACEL));
+            } else {
+                ret = reg_node(pRExC_state, (U8)(NSPACE));
+                FLAGS(ret) = (UNI_SEMANTICS) ? USE_UNI : 0;
+            }
            *flagp |= HASWIDTH|SIMPLE;
            goto finish_meta_pat;
        case 'd':
@@ -7046,12 +7421,12 @@ tryagain:
            }
            break;
         case 'N': 
-            /* Handle \N{NAME} here and not below because it can be 
+            /* Handle \N and \N{NAME} here and not below because it can be
             multicharacter. join_exact() will join them up later on. 
             Also this makes sure that things like /\N{BLAH}+/ and 
             \N{BLAH} being multi char Just Happen. dmq*/
             ++RExC_parse;
-            ret= reg_namedseq(pRExC_state, NULL); 
+            ret= reg_namedseq(pRExC_state, NULL, flagp); 
             break;
        case 'k':    /* Handle \k<NAME> and \k'NAME' */
        parse_named_seq:
@@ -7278,6 +7653,35 @@ tryagain:
                          ender = ASCII_TO_NATIVE('\007');
                        p++;
                        break;
+                   case 'o':
+                       {
+                           STRLEN brace_len = len;
+                           UV result;
+                           const char* error_msg;
+
+                           bool valid = grok_bslash_o(p,
+                                                      &result,
+                                                      &brace_len,
+                                                      &error_msg,
+                                                      1);
+                           p += brace_len;
+                           if (! valid) {
+                               RExC_parse = p; /* going to die anyway; point
+                                                  to exact spot of failure */
+                               vFAIL(error_msg);
+                           }
+                           else
+                           {
+                               ender = result;
+                           }
+                           if (PL_encoding && ender < 0x100) {
+                               goto recode_encoding;
+                           }
+                           if (ender > 0xff) {
+                               REQUIRE_UTF8;
+                           }
+                           break;
+                       }
                    case 'x':
                        if (*++p == '{') {
                            char* const e = strchr(p, '}');
@@ -7292,7 +7696,7 @@ tryagain:
                                 STRLEN numlen = e - p - 1;
                                ender = grok_hex(p + 1, &numlen, &flags, NULL);
                                if (ender > 0xff)
-                                   RExC_utf8 = 1;
+                                   REQUIRE_UTF8;
                                p = e + 1;
                            }
                        }
@@ -7307,16 +7711,19 @@ tryagain:
                        break;
                    case 'c':
                        p++;
-                       ender = UCHARAT(p++);
-                       ender = toCTRL(ender);
+                       ender = grok_bslash_c(*p++, SIZE_ONLY);
                        break;
                    case '0': case '1': case '2': case '3':case '4':
                    case '5': case '6': case '7': case '8':case '9':
                        if (*p == '0' ||
-                         (isDIGIT(p[1]) && atoi(p) >= RExC_npar) ) {
-                            I32 flags = 0;
+                           (isDIGIT(p[1]) && atoi(p) >= RExC_npar))
+                       {
+                           I32 flags = PERL_SCAN_SILENT_ILLDIGIT;
                            STRLEN numlen = 3;
                            ender = grok_oct(p, &numlen, &flags, NULL);
+                           if (ender > 0xff) {
+                               REQUIRE_UTF8;
+                           }
                            p += numlen;
                        }
                        else {
@@ -7330,9 +7737,9 @@ tryagain:
                        {
                            SV* enc = PL_encoding;
                            ender = reg_recode((const char)(U8)ender, &enc);
-                           if (!enc && SIZE_ONLY && ckWARN(WARN_REGEXP))
-                               vWARN(p, "Invalid escape in the specified encoding");
-                           RExC_utf8 = 1;
+                           if (!enc && SIZE_ONLY)
+                               ckWARNreg(p, "Invalid escape in the specified encoding");
+                           REQUIRE_UTF8;
                        }
                        break;
                    case '\0':
@@ -7340,8 +7747,8 @@ tryagain:
                            FAIL("Trailing \\");
                        /* FALL THROUGH */
                    default:
-                       if (!SIZE_ONLY&& isALPHA(*p) && ckWARN(WARN_REGEXP))
-                           vWARN2(p + 1, "Unrecognized escape \\%c passed through", UCHARAT(p));
+                       if (!SIZE_ONLY&& isALPHA(*p))
+                           ckWARN2reg(p + 1, "Unrecognized escape \\%c passed through", UCHARAT(p));
                        goto normal_default;
                    }
                    break;
@@ -7468,6 +7875,9 @@ STATIC char *
 S_regwhite( RExC_state_t *pRExC_state, char *p )
 {
     const char *e = RExC_end;
+
+    PERL_ARGS_ASSERT_REGWHITE;
+
     while (p < e) {
        if (isSPACE(*p))
            ++p;
@@ -7504,6 +7914,8 @@ S_regpposixcc(pTHX_ RExC_state_t *pRExC_state, I32 value)
     dVAR;
     I32 namedclass = OOB_NAMEDCLASS;
 
+    PERL_ARGS_ASSERT_REGPPOSIXCC;
+
     if (value == '[' && RExC_parse + 1 < RExC_end &&
        /* I smell either [: or [= or [. -- POSIX has been here, right? */
        POSIXCC(UCHARAT(RExC_parse))) {
@@ -7618,6 +8030,9 @@ STATIC void
 S_checkposixcc(pTHX_ RExC_state_t *pRExC_state)
 {
     dVAR;
+
+    PERL_ARGS_ASSERT_CHECKPOSIXCC;
+
     if (POSIXCC(UCHARAT(RExC_parse))) {
        const char *s = RExC_parse;
        const char  c = *s++;
@@ -7625,10 +8040,9 @@ S_checkposixcc(pTHX_ RExC_state_t *pRExC_state)
        while (isALNUM(*s))
            s++;
        if (*s && c == *s && s[1] == ']') {
-           if (ckWARN(WARN_REGEXP))
-               vWARN3(s+2,
-                       "POSIX syntax [%c %c] belongs inside character classes",
-                       c, c);
+           ckWARN3reg(s+2,
+                      "POSIX syntax [%c %c] belongs inside character classes",
+                      c, c);
 
            /* [[=foo=]] and [[.foo.]] are still future. */
            if (POSIXCC_NOTYET(c)) {
@@ -7667,6 +8081,7 @@ case ANYOF_N##NAME:                                     \
     what = WORD;                                        \
     break
 
+/* Like above, but no locale test */
 #define _C_C_T_NOLOC_(NAME,TEST,WORD)                   \
 ANYOF_##NAME:                                           \
        for (value = 0; value < 256; value++)           \
@@ -7683,6 +8098,58 @@ case ANYOF_N##NAME:                                     \
     what = WORD;                                        \
     break
 
+/* Like the above, but there are differences if we are in uni-8-bit or not, so
+ * there are two tests passed in, to use depending on that. There aren't any
+ * cases where the label is different from the name, so no need for that
+ * parameter */
+#define _C_C_T_UNI_8_BIT(NAME,TEST_8,TEST_7,WORD)       \
+ANYOF_##NAME:                                           \
+    if (LOC) ANYOF_CLASS_SET(ret, ANYOF_##NAME);        \
+    else if (UNI_SEMANTICS) {                           \
+        for (value = 0; value < 256; value++) {         \
+            if (TEST_8) ANYOF_BITMAP_SET(ret, value);   \
+        }                                               \
+    }                                                   \
+    else {                                              \
+        for (value = 0; value < 256; value++) {         \
+            if (TEST_7) ANYOF_BITMAP_SET(ret, value);   \
+        }                                               \
+    }                                                   \
+    yesno = '+';                                        \
+    what = WORD;                                        \
+    break;                                              \
+case ANYOF_N##NAME:                                     \
+    if (LOC) ANYOF_CLASS_SET(ret, ANYOF_N##NAME);       \
+    else if (UNI_SEMANTICS) {                           \
+        for (value = 0; value < 256; value++) {         \
+            if (! TEST_8) ANYOF_BITMAP_SET(ret, value); \
+        }                                               \
+    }                                                   \
+    else {                                              \
+        for (value = 0; value < 256; value++) {         \
+            if (! TEST_7) ANYOF_BITMAP_SET(ret, value); \
+        }                                               \
+    }                                                   \
+    yesno = '!';                                        \
+    what = WORD;                                        \
+    break
+
+/* 
+   We dont use PERL_LEGACY_UNICODE_CHARCLASS_MAPPINGS as the direct test
+   so that it is possible to override the option here without having to 
+   rebuild the entire core. as we are required to do if we change regcomp.h
+   which is where PERL_LEGACY_UNICODE_CHARCLASS_MAPPINGS is defined.
+*/
+#if PERL_LEGACY_UNICODE_CHARCLASS_MAPPINGS
+#define BROKEN_UNICODE_CHARCLASS_MAPPINGS
+#endif
+
+#ifdef BROKEN_UNICODE_CHARCLASS_MAPPINGS
+#define POSIX_CC_UNI_NAME(CCNAME) CCNAME
+#else
+#define POSIX_CC_UNI_NAME(CCNAME) "Posix" CCNAME
+#endif
+
 /*
    parse a class specification and produce either an ANYOF node that
    matches the pattern or if the pattern matches a single char only and
@@ -7716,6 +8183,8 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state, U32 depth)
         case we need to change the emitted regop to an EXACT. */
     const char * orig_parse = RExC_parse;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGCLASS;
 #ifndef DEBUGGING
     PERL_UNUSED_ARG(depth);
 #endif
@@ -7812,7 +8281,7 @@ parseit:
                     from earlier versions, OTOH that behaviour was broken
                     as well. */
                     UV v; /* value is register so we cant & it /grrr */
-                    if (reg_namedseq(pRExC_state, &v)) {
+                    if (reg_namedseq(pRExC_state, &v, NULL)) {
                         goto parseit;
                     }
                     value= v; 
@@ -7866,6 +8335,24 @@ parseit:
            case 'b':   value = '\b';                   break;
            case 'e':   value = ASCII_TO_NATIVE('\033');break;
            case 'a':   value = ASCII_TO_NATIVE('\007');break;
+           case 'o':
+               RExC_parse--;   /* function expects to be pointed at the 'o' */
+               {
+                   const char* error_msg;
+                   bool valid = grok_bslash_o(RExC_parse,
+                                              &value,
+                                              &numlen,
+                                              &error_msg,
+                                              SIZE_ONLY);
+                   RExC_parse += numlen;
+                   if (! valid) {
+                       vFAIL(error_msg);
+                   }
+               }
+               if (PL_encoding && value < 0x100) {
+                   goto recode_encoding;
+               }
+               break;
            case 'x':
                if (*RExC_parse == '{') {
                     I32 flags = PERL_SCAN_ALLOW_UNDERSCORES
@@ -7888,13 +8375,13 @@ parseit:
                    goto recode_encoding;
                break;
            case 'c':
-               value = UCHARAT(RExC_parse++);
-               value = toCTRL(value);
+               value = grok_bslash_c(*RExC_parse++, SIZE_ONLY);
                break;
            case '0': case '1': case '2': case '3': case '4':
-           case '5': case '6': case '7': case '8': case '9':
+           case '5': case '6': case '7':
                {
-                   I32 flags = 0;
+                   /* Take 1-3 octal digits */
+                   I32 flags = PERL_SCAN_SILENT_ILLDIGIT;
                    numlen = 3;
                    value = grok_oct(--RExC_parse, &numlen, &flags, NULL);
                    RExC_parse += numlen;
@@ -7906,16 +8393,18 @@ parseit:
                {
                    SV* enc = PL_encoding;
                    value = reg_recode((const char)(U8)value, &enc);
-                   if (!enc && SIZE_ONLY && ckWARN(WARN_REGEXP))
-                       vWARN(RExC_parse,
-                             "Invalid escape in the specified encoding");
+                   if (!enc && SIZE_ONLY)
+                       ckWARNreg(RExC_parse,
+                                 "Invalid escape in the specified encoding");
                    break;
                }
            default:
-               if (!SIZE_ONLY && isALPHA(value) && ckWARN(WARN_REGEXP))
-                   vWARN2(RExC_parse,
-                          "Unrecognized escape \\%c in character class passed through",
-                          (int)value);
+               /* Allow \_ to not give an error */
+               if (!SIZE_ONLY && isALNUM(value) && value != '_') {
+                   ckWARN2reg(RExC_parse,
+                              "Unrecognized escape \\%c in character class passed through",
+                              (int)value);
+               }
                break;
            }
        } /* end of \blah */
@@ -7934,14 +8423,13 @@ parseit:
            /* a bad range like a-\d, a-[:digit:] ? */
            if (range) {
                if (!SIZE_ONLY) {
-                   if (ckWARN(WARN_REGEXP)) {
-                       const int w =
-                           RExC_parse >= rangebegin ?
-                           RExC_parse - rangebegin : 0;
-                       vWARN4(RExC_parse,
+                   const int w =
+                       RExC_parse >= rangebegin ?
+                       RExC_parse - rangebegin : 0;
+                   ckWARN4reg(RExC_parse,
                               "False [] range \"%*.*s\"",
                               w, w, rangebegin);
-                   }
+
                    if (prevvalue < 256) {
                        ANYOF_BITMAP_SET(ret, prevvalue);
                        ANYOF_BITMAP_SET(ret, '-');
@@ -7969,18 +8457,26 @@ parseit:
                 * A similar issue a little earlier when switching on value.
                 * --jhi */
                switch ((I32)namedclass) {
-               case _C_C_T_(ALNUM, isALNUM(value), "Word");
-               case _C_C_T_(ALNUMC, isALNUMC(value), "Alnum");
-               case _C_C_T_(ALPHA, isALPHA(value), "Alpha");
-               case _C_C_T_(BLANK, isBLANK(value), "Blank");
-               case _C_C_T_(CNTRL, isCNTRL(value), "Cntrl");
-               case _C_C_T_(GRAPH, isGRAPH(value), "Graph");
-               case _C_C_T_(LOWER, isLOWER(value), "Lower");
-               case _C_C_T_(PRINT, isPRINT(value), "Print");
-               case _C_C_T_(PSXSPC, isPSXSPC(value), "Space");
-               case _C_C_T_(PUNCT, isPUNCT(value), "Punct");
-               case _C_C_T_(SPACE, isSPACE(value), "SpacePerl");
-               case _C_C_T_(UPPER, isUPPER(value), "Upper");
+               
+               case _C_C_T_(ALNUMC, isALNUMC(value), POSIX_CC_UNI_NAME("Alnum"));
+               case _C_C_T_(ALPHA, isALPHA(value), POSIX_CC_UNI_NAME("Alpha"));
+               case _C_C_T_(BLANK, isBLANK(value), POSIX_CC_UNI_NAME("Blank"));
+               case _C_C_T_(CNTRL, isCNTRL(value), POSIX_CC_UNI_NAME("Cntrl"));
+               case _C_C_T_(GRAPH, isGRAPH(value), POSIX_CC_UNI_NAME("Graph"));
+               case _C_C_T_(LOWER, isLOWER(value), POSIX_CC_UNI_NAME("Lower"));
+               case _C_C_T_(PRINT, isPRINT(value), POSIX_CC_UNI_NAME("Print"));
+               case _C_C_T_(PSXSPC, isPSXSPC(value), POSIX_CC_UNI_NAME("Space"));
+               case _C_C_T_(PUNCT, isPUNCT(value), POSIX_CC_UNI_NAME("Punct"));
+               case _C_C_T_(UPPER, isUPPER(value), POSIX_CC_UNI_NAME("Upper"));
+#ifdef BROKEN_UNICODE_CHARCLASS_MAPPINGS
+                /* \s, \w match all unicode if utf8. */
+                case _C_C_T_UNI_8_BIT(SPACE, isSPACE_L1(value), isSPACE(value), "SpacePerl");
+                case _C_C_T_UNI_8_BIT(ALNUM, isWORDCHAR_L1(value), isALNUM(value), "Word");
+#else
+                /* \s, \w match ascii and locale only */
+                case _C_C_T_UNI_8_BIT(SPACE, isSPACE_L1(value), isSPACE(value), "PerlSpace");
+                case _C_C_T_UNI_8_BIT(ALNUM, isWORDCHAR_L1(value), isALNUM(value), "PerlWord");
+#endif         
                case _C_C_T_(XDIGIT, isXDIGIT(value), "XDigit");
                case _C_C_T_NOLOC_(VERTWS, is_VERTWS_latin1(&value), "VertSpace");
                case _C_C_T_NOLOC_(HORIZWS, is_HORIZWS_latin1(&value), "HorizSpace");
@@ -8027,7 +8523,7 @@ parseit:
                            ANYOF_BITMAP_SET(ret, value);
                    }
                    yesno = '+';
-                   what = "Digit";
+                   what = POSIX_CC_UNI_NAME("Digit");
                    break;
                case ANYOF_NDIGIT:
                    if (LOC)
@@ -8040,7 +8536,7 @@ parseit:
                            ANYOF_BITMAP_SET(ret, value);
                    }
                    yesno = '!';
-                   what = "Digit";
+                   what = POSIX_CC_UNI_NAME("Digit");
                    break;              
                case ANYOF_MAX:
                    /* this is to handle \p and \P */
@@ -8179,8 +8675,8 @@ parseit:
 
                                  if (!unicode_alternate)
                                      unicode_alternate = newAV();
-                                 sv = newSVpvn((char*)foldbuf, foldlen);
-                                 SvUTF8_on(sv);
+                                 sv = newSVpvn_utf8((char*)foldbuf, foldlen,
+                                                    TRUE);
                                  av_push(unicode_alternate, sv);
                              }
                         }
@@ -8240,6 +8736,7 @@ parseit:
         *STRING(ret)= (char)value;
         STR_LEN(ret)= 1;
         RExC_emit += STR_SZ(1);
+       SvREFCNT_dec(listsv);
         return ret;
     }
     /* optimize case-insensitive simple patterns (e.g. /[a-z]/i) */
@@ -8276,8 +8773,8 @@ parseit:
         * used later (regexec.c:S_reginclass()). */
        av_store(av, 0, listsv);
        av_store(av, 1, NULL);
-       av_store(av, 2, (SV*)unicode_alternate);
-       rv = newRV_noinc((SV*)av);
+       av_store(av, 2, MUTABLE_SV(unicode_alternate));
+       rv = newRV_noinc(MUTABLE_SV(av));
        n = add_data(pRExC_state, 1, "s");
        RExC_rxi->data->data[n] = (void*)rv;
        ARG_SET(ret, n);
@@ -8303,6 +8800,9 @@ STATIC bool
 S_reg_skipcomment(pTHX_ RExC_state_t *pRExC_state)
 {
     bool ended = 0;
+
+    PERL_ARGS_ASSERT_REG_SKIPCOMMENT;
+
     while (RExC_parse < RExC_end)
         if (*RExC_parse++ == '\n') {
             ended = 1;
@@ -8335,6 +8835,8 @@ S_nextchar(pTHX_ RExC_state_t *pRExC_state)
 {
     char* const retval = RExC_parse++;
 
+    PERL_ARGS_ASSERT_NEXTCHAR;
+
     for (;;) {
        if (*RExC_parse == '(' && RExC_parse[1] == '?' &&
                RExC_parse[2] == '#') {
@@ -8371,6 +8873,8 @@ S_reg_node(pTHX_ RExC_state_t *pRExC_state, U8 op)
     regnode * const ret = RExC_emit;
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_REG_NODE;
+
     if (SIZE_ONLY) {
        SIZE_ALIGN(RExC_size);
        RExC_size += 1;
@@ -8410,6 +8914,8 @@ S_reganode(pTHX_ RExC_state_t *pRExC_state, U8 op, U32 arg)
     regnode * const ret = RExC_emit;
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_REGANODE;
+
     if (SIZE_ONLY) {
        SIZE_ALIGN(RExC_size);
        RExC_size += 2;
@@ -8460,6 +8966,9 @@ STATIC STRLEN
 S_reguni(pTHX_ const RExC_state_t *pRExC_state, UV uv, char* s)
 {
     dVAR;
+
+    PERL_ARGS_ASSERT_REGUNI;
+
     return SIZE_ONLY ? UNISKIP(uv) : (uvchr_to_utf8((U8*)s, uv) - (U8*)s);
 }
 
@@ -8478,6 +8987,8 @@ S_reginsert(pTHX_ RExC_state_t *pRExC_state, U8 op, regnode *opnd, U32 depth)
     const int offset = regarglen[(U8)op];
     const int size = NODE_STEP_REGNODE + offset;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGINSERT;
     PERL_UNUSED_ARG(depth);
 /* (PL_regkind[(U8)op] == CURLY ? EXTRA_STEP_2ARGS : 0); */
     DEBUG_PARSE_FMT("inst"," - %s",PL_reg_name[op]);
@@ -8560,6 +9071,8 @@ S_regtail(pTHX_ RExC_state_t *pRExC_state, regnode *p, const regnode *val,U32 de
     dVAR;
     register regnode *scan;
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGTAIL;
 #ifndef DEBUGGING
     PERL_UNUSED_ARG(depth);
 #endif
@@ -8620,9 +9133,10 @@ S_regtail_study(pTHX_ RExC_state_t *pRExC_state, regnode *p, const regnode *val,
 #ifdef EXPERIMENTAL_INPLACESCAN
     I32 min = 0;
 #endif
-
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_REGTAIL_STUDY;
+
 
     if (SIZE_ONLY)
         return exact;
@@ -8687,35 +9201,15 @@ S_regtail_study(pTHX_ RExC_state_t *pRExC_state, regnode *p, const regnode *val,
 #endif
 
 /*
- - regcurly - a little FSA that accepts {\d+,?\d*}
- */
-STATIC I32
-S_regcurly(register const char *s)
-{
-    if (*s++ != '{')
-       return FALSE;
-    if (!isDIGIT(*s))
-       return FALSE;
-    while (isDIGIT(*s))
-       s++;
-    if (*s == ',')
-       s++;
-    while (isDIGIT(*s))
-       s++;
-    if (*s != '}')
-       return FALSE;
-    return TRUE;
-}
-
-
-/*
  - regdump - dump a regexp onto Perl_debug_log in vaguely comprehensible form
  */
 #ifdef DEBUGGING
-void 
-S_regdump_extflags(pTHX_ const char *lead, const U32 flags) {
+static void 
+S_regdump_extflags(pTHX_ const char *lead, const U32 flags)
+{
     int bit;
     int set=0;
+
     for (bit=0; bit<32; bit++) {
         if (flags & (1<<bit)) {
             if (!set++ && lead) 
@@ -8742,6 +9236,8 @@ Perl_regdump(pTHX_ const regexp *r)
     RXi_GET_DECL(r,ri);
     GET_RE_DEBUG_FLAGS_DECL;
 
+    PERL_ARGS_ASSERT_REGDUMP;
+
     (void)dumpuntil(r, ri->program, ri->program + 1, NULL, NULL, sv, 0, 0);
 
     /* Header fields of interest. */
@@ -8816,6 +9312,7 @@ Perl_regdump(pTHX_ const regexp *r)
     PerlIO_printf(Perl_debug_log, "\n");
     DEBUG_FLAGS_r(regdump_extflags("r->extflags: ",r->extflags));            
 #else
+    PERL_ARGS_ASSERT_REGDUMP;
     PERL_UNUSED_CONTEXT;
     PERL_UNUSED_ARG(r);
 #endif /* DEBUGGING */
@@ -8824,6 +9321,17 @@ Perl_regdump(pTHX_ const regexp *r)
 /*
 - regprop - printable representation of opcode
 */
+#define EMIT_ANYOF_TEST_SEPARATOR(do_sep,sv,flags) \
+STMT_START { \
+        if (do_sep) {                           \
+            Perl_sv_catpvf(aTHX_ sv,"%s][%s",PL_colors[1],PL_colors[0]); \
+            if (flags & ANYOF_INVERT)           \
+                /*make sure the invert info is in each */ \
+                sv_catpvs(sv, "^");             \
+            do_sep = 0;                         \
+        }                                       \
+} STMT_END
+
 void
 Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
 {
@@ -8833,8 +9341,9 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
     RXi_GET_DECL(prog,progi);
     GET_RE_DEBUG_FLAGS_DECL;
     
+    PERL_ARGS_ASSERT_REGPROP;
 
-    sv_setpvn(sv, "", 0);
+    sv_setpvs(sv, "");
 
     if (OP(o) > REGNODE_MAX)           /* regnode.type is unsigned */
        /* It would be nice to FAIL() here, but this may be called from
@@ -8913,16 +9422,16 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
        Perl_sv_catpvf(aTHX_ sv, "[%d/%d]", o->flags & 0xf, o->flags>>4);
     else if (k == REF || k == OPEN || k == CLOSE || k == GROUPP || OP(o)==ACCEPT) {
        Perl_sv_catpvf(aTHX_ sv, "%d", (int)ARG(o));    /* Parenth number */
-       if ( prog->paren_names ) {
+       if ( RXp_PAREN_NAMES(prog) ) {
             if ( k != REF || OP(o) < NREF) {       
-               AV *list= (AV *)progi->data->data[progi->name_list_idx];
+               AV *list= MUTABLE_AV(progi->data->data[progi->name_list_idx]);
                SV **name= av_fetch(list, ARG(o), 0 );
                if (name)
                    Perl_sv_catpvf(aTHX_ sv, " '%"SVf"'", SVfARG(*name));
             }      
             else {
-                AV *list= (AV *)progi->data->data[ progi->name_list_idx ];
-                SV *sv_dat=(SV*)progi->data->data[ ARG( o ) ];
+                AV *list= MUTABLE_AV(progi->data->data[ progi->name_list_idx ]);
+                SV *sv_dat= MUTABLE_SV(progi->data->data[ ARG( o ) ]);
                 I32 *nums=(I32*)SvPVX(sv_dat);
                 SV **name= av_fetch(list, nums[0], 0 );
                 I32 n;
@@ -8940,7 +9449,7 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
     else if (k == VERB) {
         if (!o->flags) 
             Perl_sv_catpvf(aTHX_ sv, ":%"SVf, 
-                SVfARG((SV*)progi->data->data[ ARG( o ) ]));
+                          SVfARG((MUTABLE_SV(progi->data->data[ ARG( o ) ]))));
     } else if (k == LOGICAL)
        Perl_sv_catpvf(aTHX_ sv, "[%d]", o->flags);     /* 2: embedded, otherwise 1 */
     else if (k == FOLDCHAR)
@@ -8948,6 +9457,7 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
     else if (k == ANYOF) {
        int i, rangestart = -1;
        const U8 flags = ANYOF_FLAGS(o);
+       int do_sep = 0;
 
        /* Should be synchronized with * ANYOF_ #xdefines in regcomp.h */
        static const char * const anyofs[] = {
@@ -8963,8 +9473,8 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
            "[:^alpha:]",
            "[:ascii:]",
            "[:^ascii:]",
-           "[:ctrl:]",
-           "[:^ctrl:]",
+           "[:cntrl:]",
+           "[:^cntrl:]",
            "[:graph:]",
            "[:^graph:]",
            "[:lower:]",
@@ -8990,6 +9500,8 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
        Perl_sv_catpvf(aTHX_ sv, "[%s", PL_colors[0]);
        if (flags & ANYOF_INVERT)
            sv_catpvs(sv, "^");
+       
+       /* output what the standard cp 0-255 bitmap matches */
        for (i = 0; i <= 256; i++) {
            if (i < 256 && ANYOF_BITMAP_TEST(o,i)) {
                if (rangestart == -1)
@@ -9003,15 +9515,23 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
                    sv_catpvs(sv, "-");
                    put_byte(sv, i - 1);
                }
+               do_sep = 1;
                rangestart = -1;
            }
        }
-
+        
+        EMIT_ANYOF_TEST_SEPARATOR(do_sep,sv,flags);
+        /* output any special charclass tests (used mostly under use locale) */
        if (o->flags & ANYOF_CLASS)
            for (i = 0; i < (int)(sizeof(anyofs)/sizeof(char*)); i++)
-               if (ANYOF_CLASS_TEST(o,i))
+               if (ANYOF_CLASS_TEST(o,i)) {
                    sv_catpv(sv, anyofs[i]);
-
+                   do_sep = 1;
+               }
+        
+        EMIT_ANYOF_TEST_SEPARATOR(do_sep,sv,flags);
+        
+        /* output information about the unicode matching */
        if (flags & ANYOF_UNICODE)
            sv_catpvs(sv, "{unicode}");
        else if (flags & ANYOF_UNICODE_ALL)
@@ -9024,7 +9544,7 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
            if (lv) {
                if (sw) {
                    U8 s[UTF8_MAXBYTES_CASE+1];
-               
+
                    for (i = 0; i <= 256; i++) { /* just the first 256 */
                        uvchr_to_utf8(s, i);
                        
@@ -9095,10 +9615,13 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
 }
 
 SV *
-Perl_re_intuit_string(pTHX_ REGEXP * const prog)
+Perl_re_intuit_string(pTHX_ REGEXP * const r)
 {                              /* Assume that RE_INTUIT is set */
     dVAR;
+    struct regexp *const prog = (struct regexp *)SvANY(r);
     GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_RE_INTUIT_STRING;
     PERL_UNUSED_CONTEXT;
 
     DEBUG_COMPILE_r(
@@ -9134,40 +9657,38 @@ Perl_re_intuit_string(pTHX_ REGEXP * const prog)
 */
 #ifndef PERL_IN_XSUB_RE
 void
-Perl_pregfree(pTHX_ struct regexp *r)
+Perl_pregfree(pTHX_ REGEXP *r)
+{
+    SvREFCNT_dec(r);
+}
+
+void
+Perl_pregfree2(pTHX_ REGEXP *rx)
 {
     dVAR;
+    struct regexp *const r = (struct regexp *)SvANY(rx);
     GET_RE_DEBUG_FLAGS_DECL;
 
-    if (!r || (--r->refcnt > 0))
-       return;
+    PERL_ARGS_ASSERT_PREGFREE2;
+
     if (r->mother_re) {
         ReREFCNT_dec(r->mother_re);
     } else {
-        CALLREGFREE_PVT(r); /* free the private data */
-        if (r->paren_names)
-            SvREFCNT_dec(r->paren_names);
-        Safefree(RX_WRAPPED(r));
+        CALLREGFREE_PVT(rx); /* free the private data */
+        SvREFCNT_dec(RXp_PAREN_NAMES(r));
     }        
     if (r->substrs) {
-        if (r->anchored_substr)
-            SvREFCNT_dec(r->anchored_substr);
-        if (r->anchored_utf8)
-            SvREFCNT_dec(r->anchored_utf8);
-        if (r->float_substr)
-            SvREFCNT_dec(r->float_substr);
-        if (r->float_utf8)
-            SvREFCNT_dec(r->float_utf8);
+        SvREFCNT_dec(r->anchored_substr);
+        SvREFCNT_dec(r->anchored_utf8);
+        SvREFCNT_dec(r->float_substr);
+        SvREFCNT_dec(r->float_utf8);
        Safefree(r->substrs);
     }
-    RX_MATCH_COPY_FREE(r);
+    RX_MATCH_COPY_FREE(rx);
 #ifdef PERL_OLD_COPY_ON_WRITE
-    if (r->saved_copy)
-        SvREFCNT_dec(r->saved_copy);
+    SvREFCNT_dec(r->saved_copy);
 #endif
-    Safefree(r->swap);
     Safefree(r->offs);
-    Safefree(r);
 }
 
 /*  reg_temp_copy()
@@ -9187,16 +9708,33 @@ Perl_pregfree(pTHX_ struct regexp *r)
 */    
     
     
-regexp *
-Perl_reg_temp_copy (pTHX_ struct regexp *r) {
-    regexp *ret;
+REGEXP *
+Perl_reg_temp_copy (pTHX_ REGEXP *ret_x, REGEXP *rx)
+{
+    struct regexp *ret;
+    struct regexp *const r = (struct regexp *)SvANY(rx);
     register const I32 npar = r->nparens+1;
-    (void)ReREFCNT_inc(r);
-    Newx(ret, 1, regexp);
-    StructCopy(r, ret, regexp);
+
+    PERL_ARGS_ASSERT_REG_TEMP_COPY;
+
+    if (!ret_x)
+       ret_x = (REGEXP*) newSV_type(SVt_REGEXP);
+    ret = (struct regexp *)SvANY(ret_x);
+    
+    (void)ReREFCNT_inc(rx);
+    /* We can take advantage of the existing "copied buffer" mechanism in SVs
+       by pointing directly at the buffer, but flagging that the allocated
+       space in the copy is zero. As we've just done a struct copy, it's now
+       a case of zero-ing that, rather than copying the current length.  */
+    SvPV_set(ret_x, RX_WRAPPED(rx));
+    SvFLAGS(ret_x) |= SvFLAGS(rx) & (SVf_POK|SVp_POK|SVf_UTF8);
+    memcpy(&(ret->xpv_cur), &(r->xpv_cur),
+          sizeof(regexp) - STRUCT_OFFSET(regexp, xpv_cur));
+    SvLEN_set(ret_x, 0);
+    SvSTASH_set(ret_x, NULL);
+    SvMAGIC_set(ret_x, NULL);
     Newx(ret->offs, npar, regexp_paren_pair);
     Copy(r->offs, ret->offs, npar, regexp_paren_pair);
-    ret->refcnt = 1;
     if (r->substrs) {
         Newx(ret->substrs, 1, struct reg_substr_data);
        StructCopy(r->substrs, ret->substrs, struct reg_substr_data);
@@ -9209,14 +9747,13 @@ Perl_reg_temp_copy (pTHX_ struct regexp *r) {
        /* check_substr and check_utf8, if non-NULL, point to either their
           anchored or float namesakes, and don't hold a second reference.  */
     }
-    RX_MATCH_COPIED_off(ret);
+    RX_MATCH_COPIED_off(ret_x);
 #ifdef PERL_OLD_COPY_ON_WRITE
     ret->saved_copy = NULL;
 #endif
-    ret->mother_re = r; 
-    ret->swap = NULL;
+    ret->mother_re = rx;
     
-    return ret;
+    return ret_x;
 }
 #endif
 
@@ -9233,19 +9770,22 @@ Perl_reg_temp_copy (pTHX_ struct regexp *r) {
  */
  
 void
-Perl_regfree_internal(pTHX_ REGEXP * const r)
+Perl_regfree_internal(pTHX_ REGEXP * const rx)
 {
     dVAR;
+    struct regexp *const r = (struct regexp *)SvANY(rx);
     RXi_GET_DECL(r,ri);
     GET_RE_DEBUG_FLAGS_DECL;
-    
+
+    PERL_ARGS_ASSERT_REGFREE_INTERNAL;
+
     DEBUG_COMPILE_r({
        if (!PL_colorset)
            reginitcolors();
        {
            SV *dsv= sv_newmortal();
-            RE_PV_QUOTED_DECL(s, (r->extflags & RXf_UTF8),
-                dsv, RX_PRECOMP(r), RX_PRELEN(r), 60);
+            RE_PV_QUOTED_DECL(s, RX_UTF8(rx),
+                dsv, RX_PRECOMP(rx), RX_PRELEN(rx), 60);
             PerlIO_printf(Perl_debug_log,"%sFreeing REx:%s %s\n", 
                 PL_colors[4],PL_colors[5],s);
         }
@@ -9263,16 +9803,17 @@ Perl_regfree_internal(pTHX_ REGEXP * const r)
        while (--n >= 0) {
           /* If you add a ->what type here, update the comment in regcomp.h */
            switch (ri->data->what[n]) {
+           case 'a':
            case 's':
            case 'S':
            case 'u':
-               SvREFCNT_dec((SV*)ri->data->data[n]);
+               SvREFCNT_dec(MUTABLE_SV(ri->data->data[n]));
                break;
            case 'f':
                Safefree(ri->data->data[n]);
                break;
            case 'p':
-               new_comppad = (AV*)ri->data->data[n];
+               new_comppad = MUTABLE_AV(ri->data->data[n]);
                break;
            case 'o':
                if (new_comppad == NULL)
@@ -9288,7 +9829,7 @@ Perl_regfree_internal(pTHX_ REGEXP * const r)
                     op_free((OP_4tree*)ri->data->data[n]);
 
                PAD_RESTORE_LOCAL(old_comppad);
-               SvREFCNT_dec((SV*)new_comppad);
+               SvREFCNT_dec(MUTABLE_SV(new_comppad));
                new_comppad = NULL;
                break;
            case 'n':
@@ -9324,12 +9865,9 @@ Perl_regfree_internal(pTHX_ REGEXP * const r)
                         PerlMemShared_free(trie->trans);
                         if (trie->bitmap)
                             PerlMemShared_free(trie->bitmap);
-                        if (trie->wordlen)
-                            PerlMemShared_free(trie->wordlen);
                         if (trie->jump)
                             PerlMemShared_free(trie->jump);
-                        if (trie->nextword)
-                            PerlMemShared_free(trie->nextword);
+                       PerlMemShared_free(trie->wordinfo);
                         /* do this last!!!! */
                         PerlMemShared_free(ri->data->data[n]);
                    }
@@ -9346,16 +9884,15 @@ Perl_regfree_internal(pTHX_ REGEXP * const r)
     Safefree(ri);
 }
 
-#define sv_dup_inc(s,t)        SvREFCNT_inc(sv_dup(s,t))
-#define av_dup_inc(s,t)        (AV*)SvREFCNT_inc(sv_dup((SV*)s,t))
-#define hv_dup_inc(s,t)        (HV*)SvREFCNT_inc(sv_dup((SV*)s,t))
+#define av_dup_inc(s,t)        MUTABLE_AV(sv_dup_inc((const SV *)s,t))
+#define hv_dup_inc(s,t)        MUTABLE_HV(sv_dup_inc((const SV *)s,t))
 #define SAVEPVN(p,n)   ((p) ? savepvn(p,n) : NULL)
 
 /* 
    re_dup - duplicate a regexp. 
    
-   This routine is expected to clone a given regexp structure. It is not
-   compiler under USE_ITHREADS.
+   This routine is expected to clone a given regexp structure. It is only
+   compiled under USE_ITHREADS.
 
    After all of the core data stored in struct regexp is duplicated
    the regexp_engine.dupe method is used to copy any private data
@@ -9366,23 +9903,17 @@ Perl_regfree_internal(pTHX_ REGEXP * const r)
 */
 #if defined(USE_ITHREADS)
 #ifndef PERL_IN_XSUB_RE
-regexp *
-Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
+void
+Perl_re_dup_guts(pTHX_ const REGEXP *sstr, REGEXP *dstr, CLONE_PARAMS *param)
 {
     dVAR;
-    regexp *ret;
     I32 npar;
-
-    if (!r)
-       return (REGEXP *)NULL;
-
-    if ((ret = (REGEXP *)ptr_table_fetch(PL_ptr_table, r)))
-       return ret;
-
+    const struct regexp *r = (const struct regexp *)SvANY(sstr);
+    struct regexp *ret = (struct regexp *)SvANY(dstr);
     
+    PERL_ARGS_ASSERT_RE_DUP_GUTS;
+
     npar = r->nparens+1;
-    Newx(ret, 1, regexp);
-    StructCopy(r, ret, regexp);
     Newx(ret->offs, npar, regexp_paren_pair);
     Copy(r->offs, ret->offs, npar, regexp_paren_pair);
     if(ret->swap) {
@@ -9394,7 +9925,9 @@ Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
        /* Do it this way to avoid reading from *r after the StructCopy().
           That way, if any of the sv_dup_inc()s dislodge *r from the L1
           cache, it doesn't matter.  */
-       const bool anchored = r->check_substr == r->anchored_substr;
+       const bool anchored = r->check_substr
+           ? r->check_substr == r->anchored_substr
+           : r->check_utf8 == r->anchored_utf8;
         Newx(ret->substrs, 1, struct reg_substr_data);
        StructCopy(r->substrs, ret->substrs, struct reg_substr_data);
 
@@ -9417,16 +9950,21 @@ Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
                ret->check_substr = ret->float_substr;
                ret->check_utf8 = ret->float_utf8;
            }
+       } else if (ret->check_utf8) {
+           if (anchored) {
+               ret->check_utf8 = ret->anchored_utf8;
+           } else {
+               ret->check_utf8 = ret->float_utf8;
+           }
        }
     }
 
-    RX_WRAPPED(ret)     = SAVEPVN(RX_WRAPPED(ret), RX_WRAPLEN(ret)+1);
-    ret->paren_names    = hv_dup_inc(ret->paren_names, param);
+    RXp_PAREN_NAMES(ret) = hv_dup_inc(RXp_PAREN_NAMES(ret), param);
 
     if (ret->pprivate)
-       RXi_SET(ret,CALLREGDUPE_PVT(ret,param));
+       RXi_SET(ret,CALLREGDUPE_PVT(dstr,param));
 
-    if (RX_MATCH_COPIED(ret))
+    if (RX_MATCH_COPIED(dstr))
        ret->subbeg  = SAVEPVN(ret->subbeg, ret->sublen);
     else
        ret->subbeg = NULL;
@@ -9434,12 +9972,21 @@ Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
     ret->saved_copy = NULL;
 #endif
 
-    ret->mother_re      = NULL;
+    if (ret->mother_re) {
+       if (SvPVX_const(dstr) == SvPVX_const(ret->mother_re)) {
+           /* Our storage points directly to our mother regexp, but that's
+              1: a buffer in a different thread
+              2: something we no longer hold a reference on
+              so we need to copy it locally.  */
+           /* Note we need to sue SvCUR() on our mother_re, because it, in
+              turn, may well be pointing to its own mother_re.  */
+           SvPV_set(dstr, SAVEPVN(SvPVX_const(ret->mother_re),
+                                  SvCUR(ret->mother_re)+1));
+           SvLEN_set(dstr, SvCUR(ret->mother_re)+1);
+       }
+       ret->mother_re      = NULL;
+    }
     ret->gofs = 0;
-    ret->seen_evals = 0;
-    
-    ptr_table_store(PL_ptr_table, r, ret);
-    return ret;
 }
 #endif /* PERL_IN_XSUB_RE */
 
@@ -9458,17 +10005,20 @@ Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
 */
 
 void *
-Perl_regdupe_internal(pTHX_ REGEXP * const r, CLONE_PARAMS *param)
+Perl_regdupe_internal(pTHX_ REGEXP * const rx, CLONE_PARAMS *param)
 {
     dVAR;
+    struct regexp *const r = (struct regexp *)SvANY(rx);
     regexp_internal *reti;
     int len, npar;
     RXi_GET_DECL(r,ri);
+
+    PERL_ARGS_ASSERT_REGDUPE_INTERNAL;
     
     npar = r->nparens+1;
     len = ProgLen(ri);
     
-    Newxc(reti, sizeof(regexp_internal) + (len+1)*sizeof(regnode), char, regexp_internal);
+    Newxc(reti, sizeof(regexp_internal) + len*sizeof(regnode), char, regexp_internal);
     Copy(ri->program, reti->program, len+1, regnode);
     
 
@@ -9487,13 +10037,14 @@ Perl_regdupe_internal(pTHX_ REGEXP * const r, CLONE_PARAMS *param)
        for (i = 0; i < count; i++) {
            d->what[i] = ri->data->what[i];
            switch (d->what[i]) {
-               /* legal options are one of: sSfpontTu
+               /* legal options are one of: sSfpontTua
                   see also regcomp.h and pregfree() */
+           case 'a': /* actually an AV, but the dup function is identical.  */
            case 's':
            case 'S':
            case 'p': /* actually an AV, but the dup function is identical.  */
            case 'u': /* actually an HV, but the dup function is identical.  */
-               d->data[i] = sv_dup_inc((SV *)ri->data->data[i], param);
+               d->data[i] = sv_dup_inc((const SV *)ri->data->data[i], param);
                break;
            case 'f':
                /* This is cheating. */
@@ -9550,48 +10101,8 @@ Perl_regdupe_internal(pTHX_ REGEXP * const r, CLONE_PARAMS *param)
 
 #endif    /* USE_ITHREADS */
 
-/* 
-   reg_stringify() 
-   
-   converts a regexp embedded in a MAGIC struct to its stringified form, 
-   caching the converted form in the struct and returns the cached 
-   string. 
-
-   If lp is nonnull then it is used to return the length of the 
-   resulting string
-   
-   If flags is nonnull and the returned string contains UTF8 then 
-   (*flags & 1) will be true.
-   
-   If haseval is nonnull then it is used to return whether the pattern 
-   contains evals.
-   
-   Normally called via macro: 
-   
-        CALLREG_STRINGIFY(mg,&len,&utf8);
-        
-   And internally with
-   
-        CALLREG_AS_STR(mg,&lp,&flags,&haseval)        
-    
-   See sv_2pv_flags() in sv.c for an example of internal usage.
-    
- */
 #ifndef PERL_IN_XSUB_RE
 
-char *
-Perl_reg_stringify(pTHX_ MAGIC *mg, STRLEN *lp, U32 *flags, I32 *haseval ) {
-    dVAR;
-    const regexp * const re = (regexp *)mg->mg_obj;
-    if (haseval) 
-        *haseval = re->seen_evals;
-    if (flags)    
-       *flags = ((re->extflags & RXf_UTF8) ? 1 : 0);
-    if (lp)
-       *lp = RX_WRAPLEN(re);
-    return RX_WRAPPED(re);
-}
-
 /*
  - regnext - dig the "next" pointer out of a node
  */
@@ -9604,6 +10115,10 @@ Perl_regnext(pTHX_ register regnode *p)
     if (!p)
        return(NULL);
 
+    if (OP(p) > REGNODE_MAX) {         /* regnode.type is unsigned */
+       Perl_croak(aTHX_ "Corrupted regexp opcode %d > %d", (int)OP(p), (int)REGNODE_MAX);
+    }
+
     offset = (reg_off_by_arg[OP(p)] ? ARG(p) : NEXT_OFF(p));
     if (offset == 0)
        return(NULL);
@@ -9622,6 +10137,8 @@ S_re_croak2(pTHX_ const char* pat1,const char* pat2,...)
     SV *msv;
     const char *message;
 
+    PERL_ARGS_ASSERT_RE_CROAK2;
+
     if (l1 > 510)
        l1 = 510;
     if (l1 + l2 > 510)
@@ -9661,7 +10178,7 @@ Perl_save_re_context(pTHX)
 
     state = (struct re_save_state *)(PL_savestack + PL_savestack_ix);
     PL_savestack_ix += SAVESTACK_ALLOC_FOR_RE_SAVE_STATE;
-    SSPUSHINT(SAVEt_RE_STATE);
+    SSPUSHUV(SAVEt_RE_STATE);
 
     Copy(&PL_reg_state, state, 1, struct re_save_state);
 
@@ -9682,7 +10199,7 @@ Perl_save_re_context(pTHX)
        const REGEXP * const rx = PM_GETRE(PL_curpm);
        if (rx) {
            U32 i;
-           for (i = 1; i <= rx->nparens; i++) {
+           for (i = 1; i <= RX_NPARENS(rx); i++) {
                char digits[TYPE_CHARS(long)];
                const STRLEN len = my_snprintf(digits, sizeof(digits), "%lu", (long)i);
                GV *const *const gvp
@@ -9703,7 +10220,7 @@ static void
 clear_re(pTHX_ void *r)
 {
     dVAR;
-    ReREFCNT_dec((regexp *)r);
+    ReREFCNT_dec((REGEXP *)r);
 }
 
 #ifdef DEBUGGING
@@ -9711,6 +10228,8 @@ clear_re(pTHX_ void *r)
 STATIC void
 S_put_byte(pTHX_ SV *sv, int c)
 {
+    PERL_ARGS_ASSERT_PUT_BYTE;
+
     /* Our definition of isPRINT() ignores locales, so only bytes that are
        not part of UTF-8 are considered printable. I assume that the same
        holds for UTF-EBCDIC.
@@ -9752,7 +10271,9 @@ S_dumpuntil(pTHX_ const regexp *r, const regnode *start, const regnode *node,
     
     RXi_GET_DECL(r,ri);
     GET_RE_DEBUG_FLAGS_DECL;
-    
+
+    PERL_ARGS_ASSERT_DUMPUNTIL;
+
 #ifdef DEBUG_DUMPUNTIL
     PerlIO_printf(Perl_debug_log, "--- %d : %d - %d - %d\n",indent,node-start,
         last ? last-start : 0,plast ? plast-start : 0);
@@ -9818,11 +10339,11 @@ S_dumpuntil(pTHX_ const regexp *r, const regnode *start, const regnode *node,
            const reg_trie_data * const trie =
                (reg_trie_data*)ri->data->data[op<AHOCORASICK ? n : ac->trie];
 #ifdef DEBUGGING
-           AV *const trie_words = (AV *) ri->data->data[n + TRIE_WORDS_OFFSET];
+           AV *const trie_words = MUTABLE_AV(ri->data->data[n + TRIE_WORDS_OFFSET]);
 #endif
            const regnode *nextbranch= NULL;
            I32 word_idx;
-            sv_setpvn(sv, "", 0);
+            sv_setpvs(sv, "");
            for (word_idx= 0; word_idx < (I32)trie->wordcount; word_idx++) {
                SV ** const elem_ptr = av_fetch(trie_words,word_idx,0);