regcomp.c: Use '*a == b', not 'a == &b'

The latter doesn't always work.  The consequences of this failure were
memory leaks

diff --git a/regcomp.c b/regcomp.c
index 752baad..ef5b05f 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -6270,9 +6270,9 @@ Perl__invlist_populate_swatch(pTHX_ SV* const invlist, const UV start, const UV
 void
 Perl__invlist_union(pTHX_ SV* const a, SV* const b, SV** output)
 {
-    /* Take the union of two inversion lists and point 'result' to it.  If
-     * 'output' on input points to one of the two lists, the reference count to
-     * that list will be decremented.
+    /* Take the union of two inversion lists and point <output> to it.  *output
+     * should be defined upon input, and if it points to one of the two lists,
+     * the reference count to that list will be decremented.
      * The basis for this comes from "Unicode Demystified" Chapter 13 by
      * Richard Gillam, published by Addison-Wesley, and explained at some
      * length there.  The preface says to incorporate its examples into your
@@ -6313,19 +6313,19 @@ Perl__invlist_union(pTHX_ SV* const a, SV* const b, SV** output)
     /* If either one is empty, the union is the other one */
     len_a = invlist_len(a);
     if (len_a == 0) {
-       if (output == &a) {
+       if (*output == a) {
            SvREFCNT_dec(a);
        }
-       else if (output != &b) {
+       if (*output != b) {
            *output = invlist_clone(b);
        } /* else *output already = b; */
        return;
     }
     else if ((len_b = invlist_len(b)) == 0) {
-       if (output == &b) {
+       if (*output == b) {
            SvREFCNT_dec(b);
        }
-       else if (output != &a) {
+       if (*output != a) {
            *output = invlist_clone(a);
        }
        /* else *output already = a; */
@@ -6450,7 +6450,7 @@ Perl__invlist_union(pTHX_ SV* const a, SV* const b, SV** output)
     }
 
     /*  We may be removing a reference to one of the inputs */
-    if (&a == output || &b == output) {
+    if (a == *output || b == *output) {
        SvREFCNT_dec(*output);
     }
 
@@ -6461,9 +6461,9 @@ Perl__invlist_union(pTHX_ SV* const a, SV* const b, SV** output)
 void
 Perl__invlist_intersection(pTHX_ SV* const a, SV* const b, SV** i)
 {
-    /* Take the intersection of two inversion lists and point 'i' to it.  If
-     * 'i' on input points to one of the two lists, the reference count to that
-     * list will be decremented.
+    /* Take the intersection of two inversion lists and point <i> to it.  *i
+     * should be defined upon input, and if it points to one of the two lists,
+     * the reference count to that list will be decremented.
      * The basis for this comes from "Unicode Demystified" Chapter 13 by
      * Richard Gillam, published by Addison-Wesley, and explained at some
      * length there.  The preface says to incorporate its examples into your
@@ -6503,10 +6503,10 @@ Perl__invlist_intersection(pTHX_ SV* const a, SV* const b, SV** i)
 
        /* If the result is the same as one of the inputs, the input is being
         * overwritten */
-       if (i == &a) {
+       if (*i == a) {
            SvREFCNT_dec(a);
        }
-       else if (i == &b) {
+       else if (*i == b) {
            SvREFCNT_dec(b);
        }
 
@@ -6622,7 +6622,7 @@ Perl__invlist_intersection(pTHX_ SV* const a, SV* const b, SV** i)
     }
 
     /*  We may be removing a reference to one of the inputs */
-    if (&a == i || &b == i) {
+    if (a == *i || b == *i) {
        SvREFCNT_dec(*i);
     }
 
@@ -6772,7 +6772,8 @@ void
 Perl__invlist_subtract(pTHX_ SV* const a, SV* const b, SV** result)
 {
     /* Point <result> to an inversion list which consists of all elements in
-     * <a> that aren't also in <b> */
+     * <a> that aren't also in <b>.  *result should be defined upon input, and
+     * if it points to C<b> its reference count will be decremented. */
 
     PERL_ARGS_ASSERT__INVLIST_SUBTRACT;
     assert(a != b);
@@ -6786,7 +6787,7 @@ Perl__invlist_subtract(pTHX_ SV* const a, SV* const b, SV** result)
 
        /* If the result is not to be the same variable as the original, create
         * a copy */
-       if (result != &a) {
+       if (*result != a) {
            *result = invlist_clone(a);
        }
     } else {
@@ -10580,7 +10581,7 @@ parseit:
     if (FOLD && nonbitmap) {
        UV start, end;  /* End points of code point ranges */
 
-       SV* fold_intersection;
+       SV* fold_intersection = NULL;
 
        /* This is a list of all the characters that participate in folds
            * (except marks, etc in multi-char folds */