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Re: The performance problem of 30678
[perl5.git] / regcomp.c
index 93ead7c..bbff562 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -57,7 +57,7 @@
  ****    Alterations to Henry's code are...
  ****
  ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, by Larry Wall and others
+ ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 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.
@@ -109,6 +109,7 @@ typedef struct RExC_state_t {
     char       *parse;                 /* Input-scan pointer. */
     I32                whilem_seen;            /* number of WHILEM in this expr */
     regnode    *emit_start;            /* Start of emitted-code area */
+    regnode    *emit_bound;            /* First regnode outside of the allocated space */
     regnode    *emit;                  /* Code-emit pointer; &regdummy = don't = compiling */
     I32                naughty;                /* How bad is this pattern? */
     I32                sawback;                /* Did we see \1, ...? */
@@ -123,7 +124,10 @@ typedef struct RExC_state_t {
     regnode    **open_parens;          /* pointers to open parens */
     regnode    **close_parens;         /* pointers to close parens */
     regnode    *opend;                 /* END node in program */
-    I32                utf8;
+    I32                utf8;           /* whether the pattern is utf8 or not */
+    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 */
     
@@ -151,9 +155,12 @@ typedef struct RExC_state_t {
 #define RExC_end       (pRExC_state->end)
 #define RExC_parse     (pRExC_state->parse)
 #define RExC_whilem_seen       (pRExC_state->whilem_seen)
-#define RExC_offsets   (pRExC_state->rxi->offsets) /* I am not like the others */
+#ifdef RE_TRACK_PATTERN_OFFSETS
+#define RExC_offsets   (pRExC_state->rxi->u.offsets) /* I am not like the others */
+#endif
 #define RExC_emit      (pRExC_state->emit)
 #define RExC_emit_start        (pRExC_state->emit_start)
+#define RExC_emit_bound        (pRExC_state->emit_bound)
 #define RExC_naughty   (pRExC_state->naughty)
 #define RExC_sawback   (pRExC_state->sawback)
 #define RExC_seen      (pRExC_state->seen)
@@ -164,6 +171,7 @@ typedef struct RExC_state_t {
 #define RExC_seen_zerolen      (pRExC_state->seen_zerolen)
 #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)
@@ -172,6 +180,7 @@ typedef struct RExC_state_t {
 #define RExC_recurse   (pRExC_state->recurse)
 #define RExC_recurse_count     (pRExC_state->recurse_count)
 
+
 #define        ISMULT1(c)      ((c) == '*' || (c) == '+' || (c) == '?')
 #define        ISMULT2(s)      ((*s) == '*' || (*s) == '+' || (*s) == '?' || \
        ((*s) == '{' && regcurly(s)))
@@ -183,10 +192,11 @@ typedef struct RExC_state_t {
  * Flags to be passed up and down.
  */
 #define        WORST           0       /* Worst case. */
-#define        HASWIDTH        0x1     /* Known to match non-null strings. */
-#define        SIMPLE          0x2     /* Simple enough to be STAR/PLUS operand. */
-#define        SPSTART         0x4     /* Starts with * or +. */
-#define TRYAGAIN       0x8     /* Weeded out a declaration. */
+#define        HASWIDTH        0x01    /* Known to match non-null strings. */
+#define        SIMPLE          0x02    /* Simple enough to be STAR/PLUS operand. */
+#define        SPSTART         0x04    /* Starts with * or +. */
+#define TRYAGAIN       0x08    /* Weeded out a declaration. */
+#define POSTPONED      0x10    /* (?1),(?&name), (??{...}) or similar */
 
 #define REG_NODE_NUM(x) ((x) ? (int)((x)-RExC_emit_start) : -1)
 
@@ -510,7 +520,21 @@ static const scan_data_t zero_scan_data =
  * Element 0 holds the number n.
  * Position is 1 indexed.
  */
-
+#ifndef RE_TRACK_PATTERN_OFFSETS
+#define Set_Node_Offset_To_R(node,byte)
+#define Set_Node_Offset(node,byte)
+#define Set_Cur_Node_Offset
+#define Set_Node_Length_To_R(node,len)
+#define Set_Node_Length(node,len)
+#define Set_Node_Cur_Length(node)
+#define Node_Offset(n) 
+#define Node_Length(n) 
+#define Set_Node_Offset_Length(node,offset,len)
+#define ProgLen(ri) ri->u.proglen
+#define SetProgLen(ri,x) ri->u.proglen = x
+#else
+#define ProgLen(ri) ri->u.offsets[0]
+#define SetProgLen(ri,x) ri->u.offsets[0] = x
 #define Set_Node_Offset_To_R(node,byte) STMT_START {                   \
     if (! SIZE_ONLY) {                                                 \
        MJD_OFFSET_DEBUG(("** (%d) offset of node %d is %d.\n",         \
@@ -553,11 +577,11 @@ static const scan_data_t zero_scan_data =
     Set_Node_Offset_To_R((node)-RExC_emit_start, (offset));    \
     Set_Node_Length_To_R((node)-RExC_emit_start, (len));       \
 } STMT_END
-
+#endif
 
 #if PERL_ENABLE_EXPERIMENTAL_REGEX_OPTIMISATIONS
 #define EXPERIMENTAL_INPLACESCAN
-#endif
+#endif /*RE_TRACK_PATTERN_OFFSETS*/
 
 #define DEBUG_STUDYDATA(str,data,depth)                              \
 DEBUG_OPTIMISE_MORE_r(if(data){                                      \
@@ -645,7 +669,7 @@ S_scan_commit(pTHX_ const RExC_state_t *pRExC_state, scan_data_t *data, I32 *min
     }
     data->last_end = -1;
     data->flags &= ~SF_BEFORE_EOL;
-    DEBUG_STUDYDATA("cl_anything: ",data,0);
+    DEBUG_STUDYDATA("commit: ",data,0);
 }
 
 /* Can match anything (initialization) */
@@ -1355,16 +1379,17 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
         U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
         const U8 *scan = (U8*)NULL;
         U32 wordlen      = 0;         /* required init */
-        STRLEN chars=0;
+        STRLEN chars = 0;
+        bool set_bit = trie->bitmap ? 1 : 0; /*store the first char in the bitmap?*/
 
         if (OP(noper) == NOTHING) {
             trie->minlen= 0;
             continue;
         }
-        if (trie->bitmap) {
-            TRIE_BITMAP_SET(trie,*uc);
-            if ( folder ) TRIE_BITMAP_SET(trie,folder[ *uc ]);            
-        }
+        if ( set_bit ) /* bitmap only alloced when !(UTF&&Folding) */
+            TRIE_BITMAP_SET(trie,*uc); /* store the raw first byte
+                                          regardless of encoding */
+
         for ( ; uc < e ; uc += len ) {
             TRIE_CHARCOUNT(trie)++;
             TRIE_READ_CHAR;
@@ -1376,6 +1401,13 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
                         trie->charmap[ folder[ uvc ] ] = trie->charmap[ uvc ];
                     TRIE_STORE_REVCHAR;
                 }
+                if ( set_bit ) {
+                    /* store the codepoint in the bitmap, and if its ascii
+                       also store its folded equivelent. */
+                    TRIE_BITMAP_SET(trie,uvc);
+                    if ( folder ) TRIE_BITMAP_SET(trie,folder[ uvc ]);
+                    set_bit = 0; /* We've done our bit :-) */
+                }
             } else {
                 SV** svpp;
                 if ( !widecharmap )
@@ -1842,9 +1874,12 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
         
 #ifdef DEBUGGING
         regnode *optimize = NULL;
+#ifdef RE_TRACK_PATTERN_OFFSETS
+
         U32 mjd_offset = 0;
         U32 mjd_nodelen = 0;
-#endif
+#endif /* RE_TRACK_PATTERN_OFFSETS */
+#endif /* DEBUGGING */
         /*
            This means we convert either the first branch or the first Exact,
            depending on whether the thing following (in 'last') is a branch
@@ -1857,25 +1892,28 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
         if ( first != startbranch || OP( last ) == BRANCH ) {
             /* branch sub-chain */
             NEXT_OFF( first ) = (U16)(last - first);
+#ifdef RE_TRACK_PATTERN_OFFSETS
             DEBUG_r({
                 mjd_offset= Node_Offset((convert));
                 mjd_nodelen= Node_Length((convert));
             });
+#endif
             /* whole branch chain */
-        } else {
+        }
+#ifdef RE_TRACK_PATTERN_OFFSETS
+        else {
             DEBUG_r({
                 const  regnode *nop = NEXTOPER( convert );
                 mjd_offset= Node_Offset((nop));
                 mjd_nodelen= Node_Length((nop));
             });
         }
-        
         DEBUG_OPTIMISE_r(
             PerlIO_printf(Perl_debug_log, "%*sMJD offset:%"UVuf" MJD length:%"UVuf"\n",
                 (int)depth * 2 + 2, "",
                 (UV)mjd_offset, (UV)mjd_nodelen)
         );
-
+#endif
         /* But first we check to see if there is a common prefix we can 
            split out as an EXACT and put in front of the TRIE node.  */
         trie->startstate= 1;
@@ -2027,6 +2065,7 @@ S_make_trie(pTHX_ RExC_state_t *pRExC_state, regnode *startbranch, regnode *firs
         /* needed for dumping*/
         DEBUG_r(if (optimize) {
             regnode *opt = convert;
+
             while ( ++opt < optimize) {
                 Set_Node_Offset_Length(opt,0,0);
             }
@@ -4025,16 +4064,18 @@ Perl_re_compile(pTHX_ char *exp, char *xend, PMOP *pm)
     if (exp == NULL)
        FAIL("NULL regexp argument");
 
-    RExC_utf8 = pm->op_pmdynflags & PMdf_CMP_UTF8;
+    RExC_utf8 = RExC_orig_utf8 = pm->op_pmdynflags & PMdf_CMP_UTF8;
 
-    RExC_precomp = exp;
     DEBUG_COMPILE_r({
         SV *dsv= sv_newmortal();
         RE_PV_QUOTED_DECL(s, RExC_utf8,
-            dsv, RExC_precomp, (xend - exp), 60);
+            dsv, exp, (xend - exp), 60);
         PerlIO_printf(Perl_debug_log, "%sCompiling REx%s %s\n",
                       PL_colors[4],PL_colors[5],s);
     });
+
+redo_first_pass:
+    RExC_precomp = exp;
     RExC_flags = pm->op_pmflags;
     RExC_sawback = 0;
 
@@ -4073,6 +4114,25 @@ Perl_re_compile(pTHX_ char *exp, char *xend, PMOP *pm)
        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 = xend-exp;
+        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;
+    }
     DEBUG_PARSE_r({
         PerlIO_printf(Perl_debug_log, 
             "Required size %"IVdf" nodes\n"
@@ -4090,11 +4150,6 @@ Perl_re_compile(pTHX_ char *exp, char *xend, PMOP *pm)
     if (RExC_whilem_seen > 15)
        RExC_whilem_seen = 15;
 
-#ifdef DEBUGGING
-    /* Make room for a sentinel value at the end of the program */
-    RExC_size++;
-#endif
-
     /* Allocate space and zero-initialize. Note, the two step process 
        of zeroing when in debug mode, thus anything assigned has to 
        happen after that */
@@ -4116,8 +4171,51 @@ Perl_re_compile(pTHX_ char *exp, char *xend, PMOP *pm)
     r->engine= RE_ENGINE_PTR;
     r->refcnt = 1;
     r->prelen = xend - exp;
-    r->precomp = savepvn(RExC_precomp, r->prelen);
     r->extflags = pm->op_pmflags & RXf_PMf_COMPILETIME;
+    {
+        bool has_k     = ((r->extflags & RXf_PMf_KEEPCOPY) == RXf_PMf_KEEPCOPY);
+       bool has_minus = ((r->extflags & RXf_PMf_STD_PMMOD) != RXf_PMf_STD_PMMOD);
+       bool has_runon = ((RExC_seen & REG_SEEN_RUN_ON_COMMENT)==REG_SEEN_RUN_ON_COMMENT);
+       U16 reganch = (U16)((r->extflags & RXf_PMf_STD_PMMOD) >> 12);
+       const char *fptr = STD_PAT_MODS;        /*"msix"*/
+       char *p;
+        r->wraplen = r->prelen + has_minus + has_k + has_runon
+            + (sizeof(STD_PAT_MODS) - 1)
+            + (sizeof("(?:)") - 1);
+
+        Newx(r->wrapped, r->wraplen + 1, char );
+        p = r->wrapped;
+        *p++='('; *p++='?';
+        if (has_k)
+            *p++ = KEEPCOPY_PAT_MOD; /*'k'*/
+        {
+            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, r->prelen, char);
+        r->precomp = p;
+        p += r->prelen;
+        if (has_runon)
+            *p++ = '\n';
+        *p++ = ')';
+        *p = 0;
+    }
+
     r->intflags = 0;
     r->nparens = RExC_npar - 1;        /* set early to validate backrefs */
     
@@ -4129,15 +4227,14 @@ Perl_re_compile(pTHX_ char *exp, char *xend, PMOP *pm)
     }
 
     /* Useful during FAIL. */
-    Newxz(ri->offsets, 2*RExC_size+1, U32); /* MJD 20001228 */
-    if (ri->offsets) {
-       ri->offsets[0] = RExC_size;
-    }
+#ifdef RE_TRACK_PATTERN_OFFSETS
+    Newxz(ri->u.offsets, 2*RExC_size+1, U32); /* MJD 20001228 */
     DEBUG_OFFSETS_r(PerlIO_printf(Perl_debug_log,
                           "%s %"UVuf" bytes for offset annotations.\n",
-                          ri->offsets ? "Got" : "Couldn't get",
+                          ri->u.offsets ? "Got" : "Couldn't get",
                           (UV)((2*RExC_size+1) * sizeof(U32))));
-
+#endif
+    SetProgLen(ri,RExC_size);
     RExC_rx = r;
     RExC_rxi = ri;
 
@@ -4149,11 +4246,8 @@ Perl_re_compile(pTHX_ char *exp, char *xend, PMOP *pm)
     RExC_npar = 1;
     RExC_emit_start = ri->program;
     RExC_emit = ri->program;
-#ifdef DEBUGGING
-    /* put a sentinal on the end of the program so we can check for
-       overwrites */
-    ri->program[RExC_size].type = 255;
-#endif
+    RExC_emit_bound = ri->program + RExC_size + 1;
+
     /* Store the count of eval-groups for security checks: */
     RExC_rx->seen_evals = RExC_seen_evals;
     REGC((U8)REG_MAGIC, (char*) RExC_emit++);
@@ -4582,13 +4676,18 @@ reStudy:
         r->paren_names = (HV*)SvREFCNT_inc(RExC_paren_names);
     else
         r->paren_names = NULL;
+    if (r->prelen == 3 && strEQ("\\s+", r->precomp))
+       r->extflags |= RXf_WHITE;
+    else if (r->prelen == 1 && r->precomp[0] == '^')
+        r->extflags |= RXf_START_ONLY;
+
 #ifdef DEBUGGING
     if (RExC_paren_names) {
         ri->name_list_idx = add_data( pRExC_state, 1, "p" );
         ri->data->data[ri->name_list_idx] = (void*)SvREFCNT_inc(RExC_paren_name_list);
     } else
-        ri->name_list_idx = 0;
 #endif
+        ri->name_list_idx = 0;
 
     if (RExC_recurse_count) {
         for ( ; RExC_recurse_count ; RExC_recurse_count-- ) {
@@ -4596,86 +4695,91 @@ reStudy:
             ARG2L_SET( scan, RExC_open_parens[ARG(scan)-1] - scan );
         }
     }
-    Newxz(r->startp, RExC_npar, I32);
-    Newxz(r->endp, RExC_npar, I32);
+    Newxz(r->startp, RExC_npar * 2, I32);
+    r->endp = r->startp + RExC_npar;
     /* assume we don't need to swap parens around before we match */
 
     DEBUG_DUMP_r({
         PerlIO_printf(Perl_debug_log,"Final program:\n");
         regdump(r);
     });
-    DEBUG_OFFSETS_r(if (ri->offsets) {
-        const U32 len = ri->offsets[0];
+#ifdef RE_TRACK_PATTERN_OFFSETS
+    DEBUG_OFFSETS_r(if (ri->u.offsets) {
+        const U32 len = ri->u.offsets[0];
         U32 i;
         GET_RE_DEBUG_FLAGS_DECL;
-        PerlIO_printf(Perl_debug_log, "Offsets: [%"UVuf"]\n\t", (UV)ri->offsets[0]);
+        PerlIO_printf(Perl_debug_log, "Offsets: [%"UVuf"]\n\t", (UV)ri->u.offsets[0]);
         for (i = 1; i <= len; i++) {
-            if (ri->offsets[i*2-1] || ri->offsets[i*2])
+            if (ri->u.offsets[i*2-1] || ri->u.offsets[i*2])
                 PerlIO_printf(Perl_debug_log, "%"UVuf":%"UVuf"[%"UVuf"] ",
-                (UV)i, (UV)ri->offsets[i*2-1], (UV)ri->offsets[i*2]);
+                (UV)i, (UV)ri->u.offsets[i*2-1], (UV)ri->u.offsets[i*2]);
             }
         PerlIO_printf(Perl_debug_log, "\n");
     });
+#endif
     return(r);
 }
 
-#undef CORE_ONLY_BLOCK
 #undef RE_ENGINE_PTR
 
-#ifndef PERL_IN_XSUB_RE
+
 SV*
-Perl_reg_named_buff_get(pTHX_ SV* namesv, const REGEXP * const from_re, U32 flags)
+Perl_reg_named_buff_get(pTHX_ const REGEXP * const rx, SV* namesv, U32 flags)
 {
     AV *retarray = NULL;
     SV *ret;
     if (flags & 1) 
         retarray=newAV();
-    
-    if (from_re || PL_curpm) {
-        const REGEXP * const rx = from_re ? from_re : PM_GETRE(PL_curpm);
-        if (rx && rx->paren_names) {            
-            HE *he_str = hv_fetch_ent( rx->paren_names, namesv, 0, 0 );
-            if (he_str) {
-                IV i;
-                SV* sv_dat=HeVAL(he_str);
-                I32 *nums=(I32*)SvPVX(sv_dat);
-                for ( i=0; i<SvIVX(sv_dat); i++ ) {
-                    if ((I32)(rx->lastparen) >= nums[i] &&
-                        rx->endp[nums[i]] != -1) 
-                    {
-                        ret = reg_numbered_buff_get(nums[i],rx,NULL,0);
-                        if (!retarray) 
-                            return ret;
-                    } else {
-                        ret = newSVsv(&PL_sv_undef);
-                    }
-                    if (retarray) {
-                        SvREFCNT_inc(ret); 
-                        av_push(retarray, ret);
-                    }
+
+    if (rx && rx->paren_names) {
+        HE *he_str = hv_fetch_ent( rx->paren_names, namesv, 0, 0 );
+        if (he_str) {
+            IV i;
+            SV* sv_dat=HeVAL(he_str);
+            I32 *nums=(I32*)SvPVX(sv_dat);
+            for ( i=0; i<SvIVX(sv_dat); i++ ) {
+               if ((I32)(rx->nparens) >= nums[i]
+                       && rx->startp[nums[i]] != -1
+                       && rx->endp[nums[i]] != -1)
+                {
+                    ret = CALLREG_NUMBUF(rx,nums[i],NULL);
+                    if (!retarray)
+                        return ret;
+                } else {
+                    ret = newSVsv(&PL_sv_undef);
+                }
+                if (retarray) {
+                    SvREFCNT_inc(ret);
+                    av_push(retarray, ret);
                 }
-                if (retarray)
-                    return (SV*)retarray;
             }
+            if (retarray)
+                return (SV*)retarray;
         }
     }
     return NULL;
 }
 
 SV*
-Perl_reg_numbered_buff_get(pTHX_ I32 paren, const REGEXP * const rx, SV* usesv, U32 flags)
+Perl_reg_numbered_buff_get(pTHX_ const REGEXP * const rx, I32 paren, SV* usesv)
 {
     char *s = NULL;
-    I32 i;
+    I32 i = 0;
     I32 s1, t1;
     SV *sv = usesv ? usesv : newSVpvs("");
         
-    if (paren == -2 && (s = rx->subbeg) && rx->startp[0] != -1) {
+    if (!rx->subbeg) {
+        sv_setsv(sv,&PL_sv_undef);
+        return sv;
+    } 
+    else               
+    if (paren == -2 && rx->startp[0] != -1) {
         /* $` */
        i = rx->startp[0];
+       s = rx->subbeg;
     }
     else 
-    if (paren == -1 && rx->subbeg && rx->endp[0] != -1) {
+    if (paren == -1 && rx->endp[0] != -1) {
         /* $' */
        s = rx->subbeg + rx->endp[0];
        i = rx->sublen - rx->endp[0];
@@ -4688,54 +4792,50 @@ Perl_reg_numbered_buff_get(pTHX_ I32 paren, const REGEXP * const rx, SV* usesv,
         /* $& $1 ... */
         i = t1 - s1;
         s = rx->subbeg + s1;
-    }
-      
-    if (s) {        
-        assert(rx->subbeg);
-        assert(rx->sublen >= (s - rx->subbeg) + i );
-            
-        if (i >= 0) {
-            const int oldtainted = PL_tainted;
-            TAINT_NOT;
-            sv_setpvn(sv, s, i);
-            PL_tainted = oldtainted;
-            if ( (rx->extflags & RXf_CANY_SEEN)
-                ? (RX_MATCH_UTF8(rx)
-                            && (!i || is_utf8_string((U8*)s, i)))
-                : (RX_MATCH_UTF8(rx)) )
-            {
-                SvUTF8_on(sv);
-            }
-            else
-                SvUTF8_off(sv);
-            if (PL_tainting) {
-                if (RX_MATCH_TAINTED(rx)) {
-                    if (SvTYPE(sv) >= SVt_PVMG) {
-                        MAGIC* const mg = SvMAGIC(sv);
-                        MAGIC* mgt;
-                        PL_tainted = 1;
-                        SvMAGIC_set(sv, mg->mg_moremagic);
-                        SvTAINT(sv);
-                        if ((mgt = SvMAGIC(sv))) {
-                            mg->mg_moremagic = mgt;
-                            SvMAGIC_set(sv, mg);
-                        }
-                    } else {
-                        PL_tainted = 1;
-                        SvTAINT(sv);
+    } else {
+        sv_setsv(sv,&PL_sv_undef);
+        return sv;
+    }          
+    assert(rx->sublen >= (s - rx->subbeg) + i );
+    if (i >= 0) {
+        const int oldtainted = PL_tainted;
+        TAINT_NOT;
+        sv_setpvn(sv, s, i);
+        PL_tainted = oldtainted;
+        if ( (rx->extflags & RXf_CANY_SEEN)
+            ? (RX_MATCH_UTF8(rx)
+                        && (!i || is_utf8_string((U8*)s, i)))
+            : (RX_MATCH_UTF8(rx)) )
+        {
+            SvUTF8_on(sv);
+        }
+        else
+            SvUTF8_off(sv);
+        if (PL_tainting) {
+            if (RX_MATCH_TAINTED(rx)) {
+                if (SvTYPE(sv) >= SVt_PVMG) {
+                    MAGIC* const mg = SvMAGIC(sv);
+                    MAGIC* mgt;
+                    PL_tainted = 1;
+                    SvMAGIC_set(sv, mg->mg_moremagic);
+                    SvTAINT(sv);
+                    if ((mgt = SvMAGIC(sv))) {
+                        mg->mg_moremagic = mgt;
+                        SvMAGIC_set(sv, mg);
                     }
-                } else 
-                    SvTAINTED_off(sv);
-            }
-        } else {
-            sv_setsv(sv,&PL_sv_undef);
+                } else {
+                    PL_tainted = 1;
+                    SvTAINT(sv);
+                }
+            } else 
+                SvTAINTED_off(sv);
         }
     } else {
         sv_setsv(sv,&PL_sv_undef);
     }
     return sv;
 }
-#endif
+
 
 /* Scans the name of a named buffer from the pattern.
  * If flags is REG_RSN_RETURN_NULL returns null.
@@ -4813,7 +4913,7 @@ S_reg_scan_name(pTHX_ RExC_state_t *pRExC_state, U32 flags) {
         PerlIO_printf(Perl_debug_log,"%16s","");                \
                                                                 \
     if (SIZE_ONLY)                                              \
-       num=RExC_size;                                           \
+       num = RExC_size + 1;                                     \
     else                                                        \
        num=REG_NODE_NUM(RExC_emit);                             \
     if (RExC_lastnum!=num)                                      \
@@ -4854,10 +4954,6 @@ S_reg_scan_name(pTHX_ RExC_state_t *pRExC_state, U32 flags) {
 #define REGTAIL_STUDY(x,y,z) regtail((x),(y),(z),depth+1)
 #endif
 
-/* this idea is borrowed from STR_WITH_LEN in handy.h */
-#define CHECK_WORD(s,v,l)  \
-    (((sizeof(s)-1)==(l)) && (strnEQ(start_verb, (s ""), (sizeof(s)-1))))
-
 STATIC regnode *
 S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     /* paren: Parenthesized? 0=top, 1=(, inside: changed to letter. */
@@ -4872,6 +4968,8 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     const I32 oregflags = RExC_flags;
     bool have_branch = 0;
     bool is_open = 0;
+    I32 freeze_paren = 0;
+    I32 after_freeze = 0;
 
     /* for (?g), (?gc), and (?o) warnings; warning
        about (?c) will warn about (?g) -- japhy    */
@@ -4888,7 +4986,6 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     GET_RE_DEBUG_FLAGS_DECL;
     DEBUG_PARSE("reg ");
 
-
     *flagp = 0;                                /* Tentatively. */
 
 
@@ -4925,39 +5022,39 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
            
            switch ( *start_verb ) {
             case 'A':  /* (*ACCEPT) */
-                if ( CHECK_WORD("ACCEPT",start_verb,verb_len) ) {
+                if ( memEQs(start_verb,verb_len,"ACCEPT") ) {
                    op = ACCEPT;
                    internal_argval = RExC_nestroot;
                }
                break;
             case 'C':  /* (*COMMIT) */
-                if ( CHECK_WORD("COMMIT",start_verb,verb_len) )
+                if ( memEQs(start_verb,verb_len,"COMMIT") )
                     op = COMMIT;
                 break;
             case 'F':  /* (*FAIL) */
-                if ( verb_len==1 || CHECK_WORD("FAIL",start_verb,verb_len) ) {
+                if ( verb_len==1 || memEQs(start_verb,verb_len,"FAIL") ) {
                    op = OPFAIL;
                    argok = 0;
                }
                break;
             case ':':  /* (*:NAME) */
            case 'M':  /* (*MARK:NAME) */
-               if ( verb_len==0 || CHECK_WORD("MARK",start_verb,verb_len) ) {
+               if ( verb_len==0 || memEQs(start_verb,verb_len,"MARK") ) {
                     op = MARKPOINT;
                     argok = -1;
                 }
                 break;
             case 'P':  /* (*PRUNE) */
-                if ( CHECK_WORD("PRUNE",start_verb,verb_len) )
+                if ( memEQs(start_verb,verb_len,"PRUNE") )
                     op = PRUNE;
                 break;
             case 'S':   /* (*SKIP) */  
-                if ( CHECK_WORD("SKIP",start_verb,verb_len) ) 
+                if ( memEQs(start_verb,verb_len,"SKIP") ) 
                     op = SKIP;
                 break;
             case 'T':  /* (*THEN) */
                 /* [19:06] <TimToady> :: is then */
-                if ( CHECK_WORD("THEN",start_verb,verb_len) ) {
+                if ( memEQs(start_verb,verb_len,"THEN") ) {
                     op = CUTGROUP;
                     RExC_seen |= REG_SEEN_CUTGROUP;
                 }
@@ -5000,8 +5097,6 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
            return ret;
         } else 
        if (*RExC_parse == '?') { /* (?...) */
-           U32 posflags = 0, negflags = 0;
-           U32 *flagsp = &posflags;
            bool is_logical = 0;
            const char * const seqstart = RExC_parse;
 
@@ -5044,8 +5139,10 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                     nextchar(pRExC_state);
                     return ret;
                 }
-                goto unknown;
-           case '<':           /* (?<...) */
+                RExC_parse++;
+               vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
+               /*NOTREACHED*/
+            case '<':           /* (?<...) */
                if (*RExC_parse == '!')
                    paren = ',';
                else if (*RExC_parse != '=') 
@@ -5060,8 +5157,11 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                        SIZE_ONLY ?  /* reverse test from the others */
                        REG_RSN_RETURN_NAME : 
                        REG_RSN_RETURN_NULL);
-                   if (RExC_parse == name_start)
-                       goto unknown;
+                   if (RExC_parse == name_start) {
+                       RExC_parse++;
+                       vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
+                       /*NOTREACHED*/
+                    }
                    if (*RExC_parse != paren)
                        vFAIL2("Sequence (?%c... not terminated",
                            paren=='>' ? '<' : paren);
@@ -5087,11 +5187,26 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                             Perl_croak(aTHX_
                                 "panic: paren_name hash element allocation failed");
                         } else if ( SvPOK(sv_dat) ) {
-                            IV count=SvIV(sv_dat);
-                            I32 *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)++;
+                            /* (?|...) can mean we have dupes so scan to check
+                               its already been stored. Maybe a flag indicating
+                               we are inside such a construct would be useful,
+                               but the arrays are likely to be quite small, so
+                               for now we punt -- dmq */
+                            IV count = SvIV(sv_dat);
+                            I32 *pv = (I32*)SvPVX(sv_dat);
+                            IV i;
+                            for ( i = 0 ; i < count ; i++ ) {
+                                if ( pv[i] == RExC_npar ) {
+                                    count = 0;
+                                    break;
+                                }
+                            }
+                            if ( count ) {
+                                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)++;
+                            }
                         } else {
                             (void)SvUPGRADE(sv_dat,SVt_PVNV);
                             sv_setpvn(sv_dat, (char *)&(RExC_npar), sizeof(I32));
@@ -5119,6 +5234,13 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                    nextchar(pRExC_state);
                    return ret;
                }
+               break;
+           case '|':           /* (?|...) */
+               /* branch reset, behave like a (?:...) except that
+                  buffers in alternations share the same numbers */
+               paren = ':'; 
+               after_freeze = freeze_paren = RExC_npar;
+               break;
            case ':':           /* (?:...) */
            case '>':           /* (?>...) */
                break;
@@ -5139,6 +5261,7 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                if (*RExC_parse != ')')
                    FAIL("Sequence (?R) not terminated");
                ret = reg_node(pRExC_state, GOSTART);
+               *flagp |= POSTPONED;
                nextchar(pRExC_state);
                return ret;
                /*notreached*/
@@ -5219,19 +5342,20 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                 Set_Node_Length(ret, 1 + regarglen[OP(ret)]); /* MJD */
                Set_Node_Offset(ret, parse_start); /* MJD */
 
+                *flagp |= POSTPONED;
                 nextchar(pRExC_state);
                 return ret;
             } /* named and numeric backreferences */
             /* NOT REACHED */
 
-           case 'p':           /* (?p...) */
-               if (SIZE_ONLY && ckWARN2(WARN_DEPRECATED, WARN_REGEXP))
-                   vWARNdep(RExC_parse, "(?p{}) is deprecated - use (??{})");
-               /* FALL THROUGH*/
            case '?':           /* (??...) */
                is_logical = 1;
-               if (*RExC_parse != '{')
-                   goto unknown;
+               if (*RExC_parse != '{') {
+                   RExC_parse++;
+                   vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
+                   /*NOTREACHED*/
+               }
+               *flagp |= POSTPONED;
                paren = *RExC_parse++;
                /* FALL THROUGH */
            case '{':           /* (?{...}) */
@@ -5414,6 +5538,9 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                    }
                    else
                         REGTAIL(pRExC_state, ret, ender);
+                    RExC_size++; /* XXX WHY do we need this?!!
+                                    For large programs it seems to be required
+                                    but I can't figure out why. -- dmq*/
                    return ret;
                }
                else {
@@ -5425,13 +5552,20 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                 vFAIL("Sequence (? incomplete");
                 break;
            default:
-               --RExC_parse;
-             parse_flags:      /* (?i) */
-               while (*RExC_parse && strchr("iogcmsx", *RExC_parse)) {
+               --RExC_parse;
+               parse_flags:      /* (?i) */  
+           {
+                U32 posflags = 0, negflags = 0;
+               U32 *flagsp = &posflags;
+
+               while (*RExC_parse) {
+                   /* && strchr("iogcmsx", *RExC_parse) */
                    /* (?g), (?gc) and (?o) are useless here
                       and must be globally applied -- japhy */
-
-                   if (*RExC_parse == 'o' || *RExC_parse == 'g') {
+                    switch (*RExC_parse) {
+                   CASE_STD_PMMOD_FLAGS_PARSE_SET(flagsp);
+                    case 'o':
+                    case 'g':
                        if (SIZE_ONLY && ckWARN(WARN_REGEXP)) {
                            const I32 wflagbit = *RExC_parse == 'o' ? WASTED_O : WASTED_G;
                            if (! (wastedflags & wflagbit) ) {
@@ -5446,8 +5580,9 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                                );
                            }
                        }
-                   }
-                   else if (*RExC_parse == 'c') {
+                       break;
+                       
+                   case 'c':
                        if (SIZE_ONLY && ckWARN(WARN_REGEXP)) {
                            if (! (wastedflags & WASTED_C) ) {
                                wastedflags |= WASTED_GC;
@@ -5459,33 +5594,47 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
                                );
                            }
                        }
-                   }
-                   else { pmflag(flagsp, *RExC_parse); }
-
-                   ++RExC_parse;
-               }
-               if (*RExC_parse == '-') {
-                   flagsp = &negflags;
-                   wastedflags = 0;  /* reset so (?g-c) warns twice */
+                       break;
+                   case 'k':
+                        if (flagsp == &negflags) {
+                            if (SIZE_ONLY && ckWARN(WARN_REGEXP))
+                                vWARN(RExC_parse + 1,"Useless use of (?-k)");
+                        } else {
+                            *flagsp |= RXf_PMf_KEEPCOPY;
+                        }
+                       break;
+                    case '-':
+                        if (flagsp == &negflags) {
+                            RExC_parse++;
+                           vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
+                           /*NOTREACHED*/
+                       }
+                       flagsp = &negflags;
+                       wastedflags = 0;  /* reset so (?g-c) warns twice */
+                       break;
+                    case ':':
+                       paren = ':';
+                       /*FALLTHROUGH*/
+                    case ')':
+                        RExC_flags |= posflags;
+                        RExC_flags &= ~negflags;
+                        nextchar(pRExC_state);
+                       if (paren != ':') {
+                           *flagp = TRYAGAIN;
+                           return NULL;
+                       } else {
+                            ret = NULL;
+                           goto parse_rest;
+                       }
+                       /*NOTREACHED*/
+                    default:
+                       RExC_parse++;
+                       vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
+                       /*NOTREACHED*/
+                    }                           
                    ++RExC_parse;
-                   goto parse_flags;
                }
-               RExC_flags |= posflags;
-               RExC_flags &= ~negflags;
-               if (*RExC_parse == ':') {
-                   RExC_parse++;
-                   paren = ':';
-                   break;
-               }               
-             unknown:
-               if (*RExC_parse != ')') {
-                   RExC_parse++;
-                   vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
-               }
-               nextchar(pRExC_state);
-               *flagp = TRYAGAIN;
-               return NULL;
-           }
+           }} /* one for the default block, one for the switch */
        }
        else {                  /* (...) */
          capturing_parens:
@@ -5496,7 +5645,9 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
            if (!SIZE_ONLY ){
                if (!RExC_nestroot) 
                    RExC_nestroot = parno;
-               if (RExC_seen & REG_SEEN_RECURSE) {
+               if (RExC_seen & REG_SEEN_RECURSE
+                   && !RExC_open_parens[parno-1])
+               {
                    DEBUG_OPTIMISE_MORE_r(PerlIO_printf(Perl_debug_log,
                        "Setting open paren #%"IVdf" to %d\n", 
                        (IV)parno, REG_NODE_NUM(ret)));
@@ -5510,7 +5661,8 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     }
     else                        /* ! paren */
        ret = NULL;
-
+   
+   parse_rest:
     /* Pick up the branches, linking them together. */
     parse_start = RExC_parse;   /* MJD */
     br = regbranch(pRExC_state, &flags, 1,depth+1);
@@ -5539,7 +5691,7 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
     }
     else if (paren != '?')             /* Not Conditional */
        ret = br;
-    *flagp |= flags & (SPSTART | HASWIDTH);
+    *flagp |= flags & (SPSTART | HASWIDTH | POSTPONED);
     lastbr = br;
     while (*RExC_parse == '|') {
        if (!SIZE_ONLY && RExC_extralen) {
@@ -5549,15 +5701,18 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
        if (SIZE_ONLY)
            RExC_extralen += 2;         /* Account for LONGJMP. */
        nextchar(pRExC_state);
+       if (freeze_paren) {
+           if (RExC_npar > after_freeze)
+               after_freeze = RExC_npar;
+            RExC_npar = freeze_paren;      
+        }
         br = regbranch(pRExC_state, &flags, 0, depth+1);
 
        if (br == NULL)
            return(NULL);
         REGTAIL(pRExC_state, lastbr, br);               /* BRANCH -> BRANCH. */
        lastbr = br;
-       if (flags&HASWIDTH)
-           *flagp |= HASWIDTH;
-       *flagp |= flags&SPSTART;
+       *flagp |= flags & (SPSTART | HASWIDTH | POSTPONED);
     }
 
     if (have_branch || paren != ':') {
@@ -5650,7 +5805,8 @@ S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp,U32 depth)
            FAIL("Junk on end of regexp");      /* "Can't happen". */
        /* NOTREACHED */
     }
-
+    if (after_freeze)
+        RExC_npar = after_freeze;
     return(ret);
 }
 
@@ -5669,6 +5825,7 @@ S_regbranch(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, I32 first, U32 depth)
     I32 flags = 0, c = 0;
     GET_RE_DEBUG_FLAGS_DECL;
     DEBUG_PARSE("brnc");
+
     if (first)
        ret = NULL;
     else {
@@ -5697,7 +5854,7 @@ S_regbranch(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, I32 first, U32 depth)
        }
        else if (ret == NULL)
            ret = latest;
-       *flagp |= flags&HASWIDTH;
+       *flagp |= flags&(HASWIDTH|POSTPONED);
        if (chain == NULL)      /* First piece. */
            *flagp |= flags&SPSTART;
        else {
@@ -5879,7 +6036,7 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
        goto do_curly;
     }
   nest_check:
-    if (!SIZE_ONLY && !(flags&HASWIDTH) && max > REG_INFTY/3 && ckWARN(WARN_REGEXP)) {
+    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),
@@ -6104,7 +6261,9 @@ S_reg_namedseq(pTHX_ RExC_state_t *pRExC_state, UV *valuep)
         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,
@@ -6218,15 +6377,26 @@ S_reg_recode(pTHX_ const char value, SV **encp)
 
 /*
  - regatom - the lowest level
- *
- * Optimization:  gobbles an entire sequence of ordinary characters so that
- * it can turn them into a single node, which is smaller to store and
- * faster to run.  Backslashed characters are exceptions, each becoming a
- * separate node; the code is simpler that way and it's not worth fixing.
- *
- * [Yes, it is worth fixing, some scripts can run twice the speed.]
- * [It looks like its ok, as in S_study_chunk we merge adjacent EXACT nodes]
- */
+
+   Try to identify anything special at the start of the pattern. If there
+   is, then handle it as required. This may involve generating a single regop,
+   such as for an assertion; or it may involve recursing, such as to
+   handle a () structure.
+
+   If the string doesn't start with something special then we gobble up
+   as much literal text as we can.
+
+   Once we have been able to handle whatever type of thing started the
+   sequence, we return.
+
+   Note: we have to be careful with escapes, as they can be both literal
+   and special, and in the case of \10 and friends can either, depending
+   on context. Specifically there are two seperate switches for handling
+   escape sequences, with the one for handling literal escapes requiring
+   a dummy entry for all of the special escapes that are actually handled
+   by the other.
+*/
+
 STATIC regnode *
 S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
 {
@@ -6238,6 +6408,7 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
     DEBUG_PARSE("atom");
     *flagp = WORST;            /* Tentatively. */
 
+
 tryagain:
     switch (*RExC_parse) {
     case '^':
@@ -6300,7 +6471,7 @@ tryagain:
                }
                return(NULL);
        }
-       *flagp |= flags&(HASWIDTH|SPSTART|SIMPLE);
+       *flagp |= flags&(HASWIDTH|SPSTART|SIMPLE|POSTPONED);
        break;
     case '|':
     case ')':
@@ -6324,104 +6495,110 @@ tryagain:
        vFAIL("Quantifier follows nothing");
        break;
     case '\\':
+       /* Special Escapes
+
+          This switch handles escape sequences that resolve to some kind
+          of special regop and not to literal text. Escape sequnces that
+          resolve to literal text are handled below in the switch marked
+          "Literal Escapes".
+
+          Every entry in this switch *must* have a corresponding entry
+          in the literal escape switch. However, the opposite is not
+          required, as the default for this switch is to jump to the
+          literal text handling code.
+       */
        switch (*++RExC_parse) {
+       /* Special Escapes */
        case 'A':
            RExC_seen_zerolen++;
            ret = reg_node(pRExC_state, SBOL);
            *flagp |= SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'G':
            ret = reg_node(pRExC_state, GPOS);
            RExC_seen |= REG_SEEN_GPOS;
            *flagp |= SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
+       case 'K':
+           RExC_seen_zerolen++;
+           ret = reg_node(pRExC_state, KEEPS);
+           *flagp |= SIMPLE;
+           goto finish_meta_pat;
        case 'Z':
            ret = reg_node(pRExC_state, SEOL);
            *flagp |= SIMPLE;
            RExC_seen_zerolen++;                /* Do not optimize RE away */
-           nextchar(pRExC_state);
-           break;
+           goto finish_meta_pat;
        case 'z':
            ret = reg_node(pRExC_state, EOS);
            *flagp |= SIMPLE;
            RExC_seen_zerolen++;                /* Do not optimize RE away */
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'C':
            ret = reg_node(pRExC_state, CANY);
            RExC_seen |= REG_SEEN_CANY;
            *flagp |= HASWIDTH|SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'X':
            ret = reg_node(pRExC_state, CLUMP);
            *flagp |= HASWIDTH;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'w':
            ret = reg_node(pRExC_state, (U8)(LOC ? ALNUML     : ALNUM));
            *flagp |= HASWIDTH|SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'W':
            ret = reg_node(pRExC_state, (U8)(LOC ? NALNUML    : NALNUM));
            *flagp |= HASWIDTH|SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'b':
            RExC_seen_zerolen++;
            RExC_seen |= REG_SEEN_LOOKBEHIND;
            ret = reg_node(pRExC_state, (U8)(LOC ? BOUNDL     : BOUND));
            *flagp |= SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'B':
            RExC_seen_zerolen++;
            RExC_seen |= REG_SEEN_LOOKBEHIND;
            ret = reg_node(pRExC_state, (U8)(LOC ? NBOUNDL    : NBOUND));
            *flagp |= SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 's':
            ret = reg_node(pRExC_state, (U8)(LOC ? SPACEL     : SPACE));
            *flagp |= HASWIDTH|SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'S':
            ret = reg_node(pRExC_state, (U8)(LOC ? NSPACEL    : NSPACE));
            *flagp |= HASWIDTH|SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'd':
            ret = reg_node(pRExC_state, DIGIT);
            *flagp |= HASWIDTH|SIMPLE;
-           nextchar(pRExC_state);
-            Set_Node_Length(ret, 2); /* MJD */
-           break;
+           goto finish_meta_pat;
        case 'D':
            ret = reg_node(pRExC_state, NDIGIT);
            *flagp |= HASWIDTH|SIMPLE;
+           goto finish_meta_pat;
+       case 'v':
+           ret = reganode(pRExC_state, PRUNE, 0);
+           ret->flags = 1;
+           *flagp |= SIMPLE;
+           goto finish_meta_pat;
+       case 'V':
+           ret = reganode(pRExC_state, SKIP, 0);
+           ret->flags = 1;
+           *flagp |= SIMPLE;
+         finish_meta_pat:          
            nextchar(pRExC_state);
             Set_Node_Length(ret, 2); /* MJD */
-           break;
+           break;          
        case 'p':
        case 'P':
            {   
                char* const oldregxend = RExC_end;
+#ifdef DEBUGGING
                char* parse_start = RExC_parse - 2;
+#endif
 
                if (RExC_parse[1] == '{') {
                  /* a lovely hack--pretend we saw [\pX] instead */
@@ -6498,16 +6675,6 @@ tryagain:
             }
             break;
        }
-       case 'n':
-       case 'r':
-       case 't':
-       case 'f':
-       case 'e':
-       case 'a':
-       case 'x':
-       case 'c':
-       case '0':
-           goto defchar;
        case 'g': 
        case '1': case '2': case '3': case '4':
        case '5': case '6': case '7': case '8': case '9':
@@ -6582,9 +6749,7 @@ tryagain:
 
     case '#':
        if (RExC_flags & RXf_PMf_EXTENDED) {
-           while (RExC_parse < RExC_end && *RExC_parse != '\n')
-               RExC_parse++;
-           if (RExC_parse < RExC_end)
+           if ( reg_skipcomment( pRExC_state ) )
                goto tryagain;
        }
        /* FALL THROUGH */
@@ -6613,7 +6778,7 @@ tryagain:
                char * const oldp = p;
 
                if (RExC_flags & RXf_PMf_EXTENDED)
-                   p = regwhite(p, RExC_end);
+                   p = regwhite( pRExC_state, p );
                switch (*p) {
                case '^':
                case '$':
@@ -6624,29 +6789,40 @@ tryagain:
                case '|':
                    goto loopdone;
                case '\\':
+                   /* Literal Escapes Switch
+
+                      This switch is meant to handle escape sequences that
+                      resolve to a literal character.
+
+                      Every escape sequence that represents something
+                      else, like an assertion or a char class, is handled
+                      in the switch marked 'Special Escapes' above in this
+                      routine, but also has an entry here as anything that
+                      isn't explicitly mentioned here will be treated as
+                      an unescaped equivalent literal.
+                   */
+
                    switch (*++p) {
-                   case 'A':
-                   case 'C':
-                   case 'X':
-                   case 'G':
-                   case 'g':
-                   case 'Z':
-                   case 'z':
-                   case 'w':
-                   case 'W':
-                   case 'b':
-                   case 'B':
-                   case 's':
-                   case 'S':
-                   case 'd':
-                   case 'D':
-                   case 'p':
-                   case 'P':
-                    case 'N':
-                    case 'R':
-                    case 'k':
+                   /* These are all the special escapes. */
+                   case 'A':             /* Start assertion */
+                   case 'b': case 'B':   /* Word-boundary assertion*/
+                   case 'C':             /* Single char !DANGEROUS! */
+                   case 'd': case 'D':   /* digit class */
+                   case 'g': case 'G':   /* generic-backref, pos assertion */
+                   case 'k': case 'K':   /* named backref, keep marker */
+                   case 'N':             /* named char sequence */
+                   case 'p': case 'P':   /* unicode property */
+                   case 's': case 'S':   /* space class */
+                   case 'v': case 'V':   /* (*PRUNE) and (*SKIP) */
+                   case 'w': case 'W':   /* word class */
+                   case 'X':             /* eXtended Unicode "combining character sequence" */
+                   case 'z': case 'Z':   /* End of line/string assertion */
                        --p;
                        goto loopdone;
+
+                   /* Anything after here is an escape that resolves to a
+                      literal. (Except digits, which may or may not)
+                    */
                    case 'n':
                        ender = '\n';
                        p++;
@@ -6750,13 +6926,13 @@ tryagain:
                        ender = *p++;
                    break;
                }
-               if (RExC_flags & RXf_PMf_EXTENDED)
-                   p = regwhite(p, RExC_end);
+               if ( RExC_flags & RXf_PMf_EXTENDED)
+                   p = regwhite( pRExC_state, p );
                if (UTF && FOLD) {
                    /* Prime the casefolded buffer. */
                    ender = toFOLD_uni(ender, tmpbuf, &foldlen);
                }
-               if (ISMULT2(p)) { /* Back off on ?+*. */
+               if (p < RExC_end && ISMULT2(p)) { /* Back off on ?+*. */
                    if (len)
                        p = oldp;
                    else if (UTF) {
@@ -6858,15 +7034,22 @@ tryagain:
 }
 
 STATIC char *
-S_regwhite(char *p, const char *e)
+S_regwhite( RExC_state_t *pRExC_state, char *p )
 {
+    const char *e = RExC_end;
     while (p < e) {
        if (isSPACE(*p))
            ++p;
        else if (*p == '#') {
+            bool ended = 0;
            do {
-               p++;
-           } while (p < e && *p != '\n');
+               if (*p++ == '\n') {
+                   ended = 1;
+                   break;
+               }
+           } while (p < e);
+           if (!ended)
+               RExC_seen |= REG_SEEN_RUN_ON_COMMENT;
        }
        else
            break;
@@ -7587,7 +7770,7 @@ parseit:
         return ret;
     /****** !SIZE_ONLY AFTER HERE *********/
 
-    if( stored == 1 && value < 256
+    if( stored == 1 && (value < 128 || (value < 256 && !UTF))
         && !( ANYOF_FLAGS(ret) & ( ANYOF_FLAGS_ALL ^ ANYOF_FOLD ) )
     ) {
         /* optimize single char class to an EXACT node
@@ -7648,6 +7831,49 @@ parseit:
 #undef _C_C_T_
 
 
+/* reg_skipcomment()
+
+   Absorbs an /x style # comments from the input stream.
+   Returns true if there is more text remaining in the stream.
+   Will set the REG_SEEN_RUN_ON_COMMENT flag if the comment
+   terminates the pattern without including a newline.
+
+   Note its the callers responsibility to ensure that we are
+   actually in /x mode
+
+*/
+
+STATIC bool
+S_reg_skipcomment(pTHX_ RExC_state_t *pRExC_state)
+{
+    bool ended = 0;
+    while (RExC_parse < RExC_end)
+        if (*RExC_parse++ == '\n') {
+            ended = 1;
+            break;
+        }
+    if (!ended) {
+        /* we ran off the end of the pattern without ending
+           the comment, so we have to add an \n when wrapping */
+        RExC_seen |= REG_SEEN_RUN_ON_COMMENT;
+        return 0;
+    } else
+        return 1;
+}
+
+/* nextchar()
+
+   Advance that parse position, and optionall absorbs
+   "whitespace" from the inputstream.
+
+   Without /x "whitespace" means (?#...) style comments only,
+   with /x this means (?#...) and # comments and whitespace proper.
+
+   Returns the RExC_parse point from BEFORE the scan occurs.
+
+   This is the /x friendly way of saying RExC_parse++.
+*/
+
 STATIC char*
 S_nextchar(pTHX_ RExC_state_t *pRExC_state)
 {
@@ -7670,9 +7896,8 @@ S_nextchar(pTHX_ RExC_state_t *pRExC_state)
                continue;
            }
            else if (*RExC_parse == '#') {
-               while (RExC_parse < RExC_end)
-                   if (*RExC_parse++ == '\n') break;
-               continue;
+               if ( reg_skipcomment( pRExC_state ) )
+                   continue;
            }
        }
        return retval;
@@ -7695,18 +7920,17 @@ S_reg_node(pTHX_ RExC_state_t *pRExC_state, U8 op)
        RExC_size += 1;
        return(ret);
     }
-#ifdef DEBUGGING
-    if (OP(RExC_emit) == 255)
-        Perl_croak(aTHX_ "panic: reg_node overrun trying to emit %s: %d ",
-            reg_name[op], OP(RExC_emit));
-#endif  
+    if (RExC_emit >= RExC_emit_bound)
+        Perl_croak(aTHX_ "panic: reg_node overrun trying to emit %d", op);
+
     NODE_ALIGN_FILL(ret);
     ptr = ret;
     FILL_ADVANCE_NODE(ptr, op);
+#ifdef RE_TRACK_PATTERN_OFFSETS
     if (RExC_offsets) {         /* MJD */
        MJD_OFFSET_DEBUG(("%s:%d: (op %s) %s %"UVuf" (len %"UVuf") (max %"UVuf").\n", 
               "reg_node", __LINE__, 
-              reg_name[op],
+              PL_reg_name[op],
               (UV)(RExC_emit - RExC_emit_start) > RExC_offsets[0] 
                ? "Overwriting end of array!\n" : "OK",
               (UV)(RExC_emit - RExC_emit_start),
@@ -7714,7 +7938,7 @@ S_reg_node(pTHX_ RExC_state_t *pRExC_state, U8 op)
               (UV)RExC_offsets[0])); 
        Set_Node_Offset(RExC_emit, RExC_parse + (op == END));
     }
-
+#endif
     RExC_emit = ptr;
     return(ret);
 }
@@ -7749,18 +7973,18 @@ S_reganode(pTHX_ RExC_state_t *pRExC_state, U8 op, U32 arg)
        */
        return(ret);
     }
-#ifdef DEBUGGING
-    if (OP(RExC_emit) == 255)
-        Perl_croak(aTHX_ "panic: reganode overwriting end of allocated program space");
-#endif 
+    if (RExC_emit >= RExC_emit_bound)
+        Perl_croak(aTHX_ "panic: reg_node overrun trying to emit %d", op);
+
     NODE_ALIGN_FILL(ret);
     ptr = ret;
     FILL_ADVANCE_NODE_ARG(ptr, op, arg);
+#ifdef RE_TRACK_PATTERN_OFFSETS
     if (RExC_offsets) {         /* MJD */
        MJD_OFFSET_DEBUG(("%s(%d): (op %s) %s %"UVuf" <- %"UVuf" (max %"UVuf").\n", 
               "reganode",
              __LINE__,
-             reg_name[op],
+             PL_reg_name[op],
               (UV)(RExC_emit - RExC_emit_start) > RExC_offsets[0] ? 
               "Overwriting end of array!\n" : "OK",
               (UV)(RExC_emit - RExC_emit_start),
@@ -7768,7 +7992,7 @@ S_reganode(pTHX_ RExC_state_t *pRExC_state, U8 op, U32 arg)
               (UV)RExC_offsets[0])); 
        Set_Cur_Node_Offset;
     }
-            
+#endif            
     RExC_emit = ptr;
     return(ret);
 }
@@ -7798,8 +8022,9 @@ 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_UNUSED_ARG(depth);
 /* (PL_regkind[(U8)op] == CURLY ? EXTRA_STEP_2ARGS : 0); */
-    DEBUG_PARSE_FMT("inst"," - %s",reg_name[op]);
+    DEBUG_PARSE_FMT("inst"," - %s",PL_reg_name[op]);
     if (SIZE_ONLY) {
        RExC_size += size;
        return;
@@ -7810,30 +8035,31 @@ S_reginsert(pTHX_ RExC_state_t *pRExC_state, U8 op, regnode *opnd, U32 depth)
     dst = RExC_emit;
     if (RExC_open_parens) {
         int paren;
-        DEBUG_PARSE_FMT("inst"," - %"IVdf, (IV)RExC_npar);
+        /*DEBUG_PARSE_FMT("inst"," - %"IVdf, (IV)RExC_npar);*/
         for ( paren=0 ; paren < RExC_npar ; paren++ ) {
             if ( RExC_open_parens[paren] >= opnd ) {
-                DEBUG_PARSE_FMT("open"," - %d",size);
+                /*DEBUG_PARSE_FMT("open"," - %d",size);*/
                 RExC_open_parens[paren] += size;
             } else {
-                DEBUG_PARSE_FMT("open"," - %s","ok");
+                /*DEBUG_PARSE_FMT("open"," - %s","ok");*/
             }
             if ( RExC_close_parens[paren] >= opnd ) {
-                DEBUG_PARSE_FMT("close"," - %d",size);
+                /*DEBUG_PARSE_FMT("close"," - %d",size);*/
                 RExC_close_parens[paren] += size;
             } else {
-                DEBUG_PARSE_FMT("close"," - %s","ok");
+                /*DEBUG_PARSE_FMT("close"," - %s","ok");*/
             }
         }
     }
 
     while (src > opnd) {
        StructCopy(--src, --dst, regnode);
+#ifdef RE_TRACK_PATTERN_OFFSETS
         if (RExC_offsets) {     /* MJD 20010112 */
            MJD_OFFSET_DEBUG(("%s(%d): (op %s) %s copy %"UVuf" -> %"UVuf" (max %"UVuf").\n",
                   "reg_insert",
                  __LINE__,
-                 reg_name[op],
+                 PL_reg_name[op],
                   (UV)(dst - RExC_emit_start) > RExC_offsets[0] 
                    ? "Overwriting end of array!\n" : "OK",
                   (UV)(src - RExC_emit_start),
@@ -7842,15 +8068,17 @@ S_reginsert(pTHX_ RExC_state_t *pRExC_state, U8 op, regnode *opnd, U32 depth)
            Set_Node_Offset_To_R(dst-RExC_emit_start, Node_Offset(src));
            Set_Node_Length_To_R(dst-RExC_emit_start, Node_Length(src));
         }
+#endif
     }
     
 
     place = opnd;              /* Op node, where operand used to be. */
+#ifdef RE_TRACK_PATTERN_OFFSETS
     if (RExC_offsets) {         /* MJD */
        MJD_OFFSET_DEBUG(("%s(%d): (op %s) %s %"UVuf" <- %"UVuf" (max %"UVuf").\n", 
               "reginsert",
              __LINE__,
-             reg_name[op],
+             PL_reg_name[op],
               (UV)(place - RExC_emit_start) > RExC_offsets[0] 
               ? "Overwriting end of array!\n" : "OK",
               (UV)(place - RExC_emit_start),
@@ -7859,6 +8087,7 @@ S_reginsert(pTHX_ RExC_state_t *pRExC_state, U8 op, regnode *opnd, U32 depth)
        Set_Node_Offset(place, RExC_parse);
        Set_Node_Length(place, 1);
     }
+#endif    
     src = NEXTOPER(place);
     FILL_ADVANCE_NODE(place, op);
     Zero(src, offset, regnode);
@@ -7893,7 +8122,7 @@ S_regtail(pTHX_ RExC_state_t *pRExC_state, regnode *p, const regnode *val,U32 de
             PerlIO_printf(Perl_debug_log, "~ %s (%d) %s %s\n",
                 SvPV_nolen_const(mysv), REG_NODE_NUM(scan),
                     (temp == NULL ? "->" : ""),
-                    (temp == NULL ? reg_name[OP(val)] : "")
+                    (temp == NULL ? PL_reg_name[OP(val)] : "")
             );
         });
         if (temp == NULL)
@@ -7974,7 +8203,7 @@ S_regtail_study(pTHX_ RExC_state_t *pRExC_state, regnode *p, const regnode *val,
             PerlIO_printf(Perl_debug_log, "~ %s (%d) -> %s\n",
                 SvPV_nolen_const(mysv),
                 REG_NODE_NUM(scan),
-                reg_name[exact]);
+                PL_reg_name[exact]);
         });
        if (temp == NULL)
            break;
@@ -8132,7 +8361,7 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
        /* It would be nice to FAIL() here, but this may be called from
           regexec.c, and it would be hard to supply pRExC_state. */
        Perl_croak(aTHX_ "Corrupted regexp opcode %d > %d", (int)OP(o), (int)REGNODE_MAX);
-    sv_catpv(sv, reg_name[OP(o)]); /* Take off const! */
+    sv_catpv(sv, PL_reg_name[OP(o)]); /* Take off const! */
 
     k = PL_regkind[OP(o)];
 
@@ -8154,14 +8383,14 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
        /* print the details of the trie in dumpuntil instead, as
         * progi->data isn't available here */
         const char op = OP(o);
-        const I32 n = ARG(o);
+        const U32 n = ARG(o);
         const reg_ac_data * const ac = IS_TRIE_AC(op) ?
                (reg_ac_data *)progi->data->data[n] :
                NULL;
         const reg_trie_data * const trie
            = (reg_trie_data*)progi->data->data[!IS_TRIE_AC(op) ? n : ac->trie];
         
-        Perl_sv_catpvf(aTHX_ sv, "-%s",reg_name[o->flags]);
+        Perl_sv_catpvf(aTHX_ sv, "-%s",PL_reg_name[o->flags]);
         DEBUG_TRIE_COMPILE_r(
             Perl_sv_catpvf(aTHX_ sv,
                 "<S:%"UVuf"/%"IVdf" W:%"UVuf" L:%"UVuf"/%"UVuf" C:%"UVuf"/%"UVuf">",
@@ -8208,26 +8437,27 @@ Perl_regprop(pTHX_ const regexp *prog, SV *sv, const regnode *o)
     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 ) {
-           AV *list= (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 if (k == NREF) {
-        if ( prog->paren_names ) {
-            AV *list= (AV *)progi->data->data[ progi->name_list_idx ];
-            SV *sv_dat=(SV*)progi->data->data[ ARG( o ) ];
-            I32 *nums=(I32*)SvPVX(sv_dat);
-            SV **name= av_fetch(list, nums[0], 0 );
-            I32 n;
-            if (name) {
-                for ( n=0; n<SvIVX(sv_dat); n++ ) {
-                    Perl_sv_catpvf(aTHX_ sv, "%s%"IVdf,
-                                  (n ? "," : ""), (IV)nums[n]);
+            if ( k != REF || OP(o) < NREF) {       
+               AV *list= (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 ) ];
+                I32 *nums=(I32*)SvPVX(sv_dat);
+                SV **name= av_fetch(list, nums[0], 0 );
+                I32 n;
+                if (name) {
+                    for ( n=0; n<SvIVX(sv_dat); n++ ) {
+                        Perl_sv_catpvf(aTHX_ sv, "%s%"IVdf,
+                                   (n ? "," : ""), (IV)nums[n]);
+                    }
+                    Perl_sv_catpvf(aTHX_ sv, " '%"SVf"'", SVfARG(*name));
                 }
-                Perl_sv_catpvf(aTHX_ sv, " '%"SVf"'", SVfARG(*name));
             }
-        }
+        }            
     } else if (k == GOSUB) 
        Perl_sv_catpvf(aTHX_ sv, "%d[%+d]", (int)ARG(o),(int)ARG2L(o)); /* Paren and offset */
     else if (k == VERB) {
@@ -8432,35 +8662,108 @@ Perl_pregfree(pTHX_ struct regexp *r)
 
     if (!r || (--r->refcnt > 0))
        return;
-       
-    CALLREGFREE_PVT(r); /* free the private data */
-    
-    /* gcov results gave these as non-null 100% of the time, so there's no
-       optimisation in checking them before calling Safefree  */
-    Safefree(r->precomp);
+    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(r->wrapped);
+    }        
+    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);
+       Safefree(r->substrs);
+    }
     RX_MATCH_COPY_FREE(r);
 #ifdef PERL_OLD_COPY_ON_WRITE
     if (r->saved_copy)
-       SvREFCNT_dec(r->saved_copy);
+        SvREFCNT_dec(r->saved_copy);
 #endif
-    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);
-       Safefree(r->substrs);
+    if (r->swap) {
+        Safefree(r->swap->startp);
+        Safefree(r->swap);
     }
-    if (r->paren_names)
-            SvREFCNT_dec(r->paren_names);
-    
     Safefree(r->startp);
-    Safefree(r->endp);
     Safefree(r);
 }
+
+/*  reg_temp_copy()
+    
+    This is a hacky workaround to the structural issue of match results
+    being stored in the regexp structure which is in turn stored in
+    PL_curpm/PL_reg_curpm. The problem is that due to qr// the pattern
+    could be PL_curpm in multiple contexts, and could require multiple
+    result sets being associated with the pattern simultaneously, such
+    as when doing a recursive match with (??{$qr})
+    
+    The solution is to make a lightweight copy of the regexp structure 
+    when a qr// is returned from the code executed by (??{$qr}) this
+    lightweight copy doesnt actually own any of its data except for
+    the starp/end and the actual regexp structure itself. 
+    
+*/    
+    
+    
+regexp *
+Perl_reg_temp_copy (pTHX_ struct regexp *r) {
+    regexp *ret;
+    register const I32 npar = r->nparens+1;
+    (void)ReREFCNT_inc(r);
+    Newx(ret, 1, regexp);
+    StructCopy(r, ret, regexp);
+    Newx(ret->startp, npar * 2, I32);
+    Copy(r->startp, ret->startp, npar * 2, I32);
+    ret->endp = ret->startp + npar;
+    ret->refcnt = 1;
+    if (r->substrs) {
+        struct reg_substr_datum *s;
+        I32 i;
+        Newx(ret->substrs, 1, struct reg_substr_data);
+        for (s = ret->substrs->data, i = 0; i < 3; i++, s++) {
+            s->min_offset = r->substrs->data[i].min_offset;
+            s->max_offset = r->substrs->data[i].max_offset;
+            s->end_shift  = r->substrs->data[i].end_shift;
+            if (i < 2) {
+               s->substr      = SvREFCNT_inc(r->substrs->data[i].substr);
+               s->utf8_substr = SvREFCNT_inc(r->substrs->data[i].utf8_substr);
+           }
+        }
+       if (r->check_substr == r->anchored_substr)
+           ret->check_substr = ret->anchored_substr;
+       else if (r->check_substr == r->float_substr)
+           ret->check_substr = ret->float_substr;
+       else {
+           assert(!r->check_substr);
+           ret->check_substr = NULL;
+       }
+       if (r->check_utf8 == r->anchored_utf8)
+           ret->check_utf8 = ret->anchored_utf8;
+       else if (r->check_utf8 == r->float_utf8)
+           ret->check_utf8 = ret->float_utf8;
+       else {
+           assert(!r->check_utf8);
+           ret->check_utf8 = NULL;
+       }
+    }
+    RX_MATCH_COPIED_off(ret);
+#ifdef PERL_OLD_COPY_ON_WRITE
+    /* this is broken. */
+    assert(0); 
+    if (ret->saved_copy)
+        ret->saved_copy=NULL;
+#endif
+    ret->mother_re = r; 
+    ret->swap = NULL;
+    
+    return ret;
+}
 #endif
 
 /* regfree_internal() 
@@ -8493,8 +8796,10 @@ Perl_regfree_internal(pTHX_ struct regexp *r)
                 PL_colors[4],PL_colors[5],s);
         }
     });
-
-    Safefree(ri->offsets);             /* 20010421 MJD */
+#ifdef RE_TRACK_PATTERN_OFFSETS
+    if (ri->u.offsets)
+        Safefree(ri->u.offsets);             /* 20010421 MJD */
+#endif
     if (ri->data) {
        int n = ri->data->count;
        PAD* new_comppad = NULL;
@@ -8583,11 +8888,7 @@ Perl_regfree_internal(pTHX_ struct regexp *r)
        Safefree(ri->data->what);
        Safefree(ri->data);
     }
-    if (ri->swap) {
-        Safefree(ri->swap->startp);
-        Safefree(ri->swap->endp);
-        Safefree(ri->swap);
-    }
+
     Safefree(ri);
 }
 
@@ -8617,8 +8918,7 @@ Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
 {
     dVAR;
     regexp *ret;
-    int i, npar;
-    struct reg_substr_datum *s;
+    I32 npar;
 
     if (!r)
        return (REGEXP *)NULL;
@@ -8629,28 +8929,45 @@ Perl_re_dup(pTHX_ const regexp *r, CLONE_PARAMS *param)
     
     npar = r->nparens+1;
     Newxz(ret, 1, regexp);
-    Newx(ret->startp, npar, I32);
-    Copy(r->startp, ret->startp, npar, I32);
-    Newx(ret->endp, npar, I32);
-    Copy(r->endp, ret->endp, npar, I32);
+    Newx(ret->startp, npar * 2, I32);
+    Copy(r->startp, ret->startp, npar * 2, I32);
+    ret->endp = ret->startp + npar;
+    if(r->swap) {
+        Newx(ret->swap, 1, regexp_paren_ofs);
+        /* no need to copy these */
+        Newx(ret->swap->startp, npar * 2, I32);
+       ret->swap->endp = ret->swap->startp + npar;
+    } else {
+        ret->swap = NULL;
+    }
 
     if (r->substrs) {
+       struct reg_substr_datum *s;
+       const struct reg_substr_datum *s_end;
+
         Newx(ret->substrs, 1, struct reg_substr_data);
-        for (s = ret->substrs->data, i = 0; i < 3; i++, s++) {
-            s->min_offset = r->substrs->data[i].min_offset;
-            s->max_offset = r->substrs->data[i].max_offset;
-            s->end_shift  = r->substrs->data[i].end_shift;
-            s->substr     = sv_dup_inc(r->substrs->data[i].substr, param);
-            s->utf8_substr = sv_dup_inc(r->substrs->data[i].utf8_substr, param);
-        }
+       StructCopy(r->substrs, ret->substrs, struct reg_substr_data);
+
+       s = ret->substrs->data;
+       s_end
+           = s + sizeof(ret->substrs->data) / sizeof(struct reg_substr_datum);
+
+       do {
+            s->substr      = sv_dup_inc(s->substr, param);
+            s->utf8_substr = sv_dup_inc(s->utf8_substr, param);
+        } while (++s < s_end);
     } else 
         ret->substrs = NULL;    
 
-    ret->precomp        = SAVEPVN(r->precomp, r->prelen);
+    ret->wrapped        = SAVEPVN(r->wrapped, r->wraplen+1);
+    ret->precomp        = ret->wrapped + (r->precomp - r->wrapped);
+    ret->prelen         = r->prelen;
+    ret->wraplen        = r->wraplen;
+
+    ret->mother_re      = NULL;
     ret->refcnt         = r->refcnt;
     ret->minlen         = r->minlen;
     ret->minlenret      = r->minlenret;
-    ret->prelen         = r->prelen;
     ret->nparens        = r->nparens;
     ret->lastparen      = r->lastparen;
     ret->lastcloseparen = r->lastcloseparen;
@@ -8703,22 +9020,14 @@ Perl_regdupe_internal(pTHX_ const regexp *r, CLONE_PARAMS *param)
     RXi_GET_DECL(r,ri);
     
     npar = r->nparens+1;
-    len = ri->offsets[0];
+    len = ProgLen(ri);
     
     Newxc(reti, sizeof(regexp_internal) + (len+1)*sizeof(regnode), char, regexp_internal);
     Copy(ri->program, reti->program, len+1, regnode);
     
-    if(ri->swap) {
-        Newx(reti->swap, 1, regexp_paren_ofs);
-        /* no need to copy these */
-        Newx(reti->swap->startp, npar, I32);
-        Newx(reti->swap->endp, npar, I32);
-    } else {
-        reti->swap = NULL;
-    }
-
 
     reti->regstclass = NULL;
+
     if (ri->data) {
        struct reg_data *d;
         const int count = ri->data->count;
@@ -8779,9 +9088,17 @@ Perl_regdupe_internal(pTHX_ const regexp *r, CLONE_PARAMS *param)
     else
        reti->data = NULL;
 
-    Newx(reti->offsets, 2*len+1, U32);
-    Copy(ri->offsets, reti->offsets, 2*len+1, U32);
-    
+    reti->name_list_idx = ri->name_list_idx;
+
+#ifdef RE_TRACK_PATTERN_OFFSETS
+    if (ri->u.offsets) {
+        Newx(reti->u.offsets, 2*len+1, U32);
+        Copy(ri->u.offsets, reti->u.offsets, 2*len+1, U32);
+    }
+#else
+    SetProgLen(reti,len);
+#endif
+
     return (void*)reti;
 }
 
@@ -8815,80 +9132,18 @@ Perl_regdupe_internal(pTHX_ const regexp *r, CLONE_PARAMS *param)
     
  */
 #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 (!mg->mg_ptr) {
-       const char *fptr = "msix";
-       char reflags[6];
-       char ch;
-       int left = 0;
-       int right = 4;
-       bool need_newline = 0;
-       U16 reganch = (U16)((re->extflags & RXf_PMf_COMPILETIME) >> 12);
-
-       while((ch = *fptr++)) {
-           if(reganch & 1) {
-               reflags[left++] = ch;
-           }
-           else {
-               reflags[right--] = ch;
-           }
-           reganch >>= 1;
-       }
-       if(left != 4) {
-           reflags[left] = '-';
-           left = 5;
-       }
-
-       mg->mg_len = re->prelen + 4 + left;
-       /*
-        * If /x was used, we have to worry about a regex ending with a
-        * comment later being embedded within another regex. If so, we don't
-        * want this regex's "commentization" to leak out to the right part of
-        * the enclosing regex, we must cap it with a newline.
-        *
-        * So, if /x was used, we scan backwards from the end of the regex. If
-        * we find a '#' before we find a newline, we need to add a newline
-        * ourself. If we find a '\n' first (or if we don't find '#' or '\n'),
-        * we don't need to add anything.  -jfriedl
-        */
-       if (PMf_EXTENDED & re->extflags) {
-           const char *endptr = re->precomp + re->prelen;
-           while (endptr >= re->precomp) {
-               const char c = *(endptr--);
-               if (c == '\n')
-                   break; /* don't need another */
-               if (c == '#') {
-                   /* we end while in a comment, so we need a newline */
-                   mg->mg_len++; /* save space for it */
-                   need_newline = 1; /* note to add it */
-                   break;
-               }
-           }
-       }
-
-       Newx(mg->mg_ptr, mg->mg_len + 1 + left, char);
-       mg->mg_ptr[0] = '(';
-       mg->mg_ptr[1] = '?';
-       Copy(reflags, mg->mg_ptr+2, left, char);
-       *(mg->mg_ptr+left+2) = ':';
-       Copy(re->precomp, mg->mg_ptr+3+left, re->prelen, char);
-       if (need_newline)
-           mg->mg_ptr[mg->mg_len - 2] = '\n';
-       mg->mg_ptr[mg->mg_len - 1] = ')';
-       mg->mg_ptr[mg->mg_len] = 0;
-    }
     if (haseval) 
         *haseval = re->seen_evals;
     if (flags)    
        *flags = ((re->extflags & RXf_UTF8) ? 1 : 0);
-    
     if (lp)
-       *lp = mg->mg_len;
-    return mg->mg_ptr;
+       *lp = re->wraplen;
+    return re->wrapped;
 }
 
 /*
@@ -9098,7 +9353,7 @@ S_dumpuntil(pTHX_ const regexp *r, const regnode *start, const regnode *node,
        else if ( PL_regkind[(U8)op]  == TRIE ) {
            const regnode *this_trie = node;
            const char op = OP(node);
-            const I32 n = ARG(node);
+            const U32 n = ARG(node);
            const reg_ac_data * const ac = op>=AHOCORASICK ?
                (reg_ac_data *)ri->data->data[n] :
                NULL;