# http://rt.perl.org/rt3/Public/Bug/Display.html?id=53038
# http://perl5.git.perl.org/perl.git/commitdiff/414bf5ae0886eb91e2f6dbb35893ddb012852bef?hp=2556f95e0f4f5e8e95c9766374614ab52edefe3d
diff --git a/XSUB.h b/XSUB.h
index 46e9c29..2d95b1e 100644
--- XSUB.h
+++ XSUB.h
@@ -364,10 +364,10 @@ Rethrows a previously caught exception.  See L<perlguts/"Exception Handling">.
 	    SAVETMPS ;						\
 	    SAVEINT(db->filtering) ;				\
 	    db->filtering = TRUE ;				\
-	    SAVESPTR(DEFSV) ;					\
+	    SAVE_DEFSV ;					\
             if (name[7] == 's')                                 \
                 arg = newSVsv(arg);                             \
-	    DEFSV = arg ;					\
+	    DEFSV_set(arg) ;					\
 	    SvTEMP_off(arg) ;					\
 	    PUSHMARK(SP) ;					\
 	    PUTBACK ;						\
diff --git a/perl.h b/perl.h
index e07416e..526155b 100644
--- perl.h
+++ perl.h
@@ -1306,8 +1306,12 @@ EXTERN_C char *crypt(const char *, const char *);
 #endif
 
 #define ERRSV GvSV(PL_errgv)
-/* FIXME? Change the assignments to PL_defgv to instantiate GvSV?  */
-#define DEFSV GvSVn(PL_defgv)
+#ifdef PERL_CORE
+# define DEFSV (0 + GvSVn(PL_defgv))
+#else
+# define DEFSV GvSVn(PL_defgv)
+#endif
+#define DEFSV_set(sv) (GvSV(PL_defgv) = (sv))
 #define SAVE_DEFSV SAVESPTR(GvSV(PL_defgv))
 
 #define ERRHV GvHV(PL_errgv)	/* XXX unused, here for compatibility */
diff --git a/pp_ctl.c b/pp_ctl.c
index 08b14c6..3ef7e32 100644
--- pp_ctl.c
+++ pp_ctl.c
@@ -988,7 +988,7 @@ PP(pp_grepstart)
     if (PL_op->op_private & OPpGREP_LEX)
 	PAD_SVl(PL_op->op_targ) = src;
     else
-	DEFSV = src;
+	DEFSV_set(src);
 
     PUTBACK;
     if (PL_op->op_type == OP_MAPSTART)
@@ -1099,7 +1099,7 @@ PP(pp_mapwhile)
 	if (PL_op->op_private & OPpGREP_LEX)
 	    PAD_SVl(PL_op->op_targ) = src;
 	else
-	    DEFSV = src;
+	    DEFSV_set(src);
 
 	RETURNOP(cLOGOP->op_other);
     }
@@ -4822,7 +4822,7 @@ S_run_user_filter(pTHX_ int idx, SV *buf_sv, int maxlen)
 	SAVETMPS;
 	EXTEND(SP, 2);
 
-	DEFSV = upstream;
+	DEFSV_set(upstream);
 	PUSHMARK(SP);
 	mPUSHi(0);
 	if (filter_state) {
diff --git a/pp_hot.c b/pp_hot.c
index eeedc5b..6450e25 100644
--- pp_hot.c
+++ pp_hot.c
@@ -2424,7 +2424,7 @@ PP(pp_grepwhile)
 	if (PL_op->op_private & OPpGREP_LEX)
 	    PAD_SVl(PL_op->op_targ) = src;
 	else
-	    DEFSV = src;
+	    DEFSV_set(src);
 
 	RETURNOP(cLOGOP->op_other);
     }
diff --git a/regexec.c b/regexec.c
index 025d159..6c0923f 100644
--- regexec.c
+++ regexec.c
@@ -2250,7 +2250,7 @@ S_regtry(pTHX_ regmatch_info *reginfo, char **startpos)
 	    /* Make $_ available to executed code. */
 	    if (reginfo->sv != DEFSV) {
 		SAVE_DEFSV;
-		DEFSV = reginfo->sv;
+		DEFSV_set(reginfo->sv);
 	    }
 	
 	    if (!(SvTYPE(reginfo->sv) >= SVt_PVMG && SvMAGIC(reginfo->sv)