In Perl_mg_dup(), remove a branch by tracking the address to write to instead of

the address of the structure, with a special case for the first time round.

diff --git a/sv.c b/sv.c
index 0b95142..70e6a9b 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -10509,18 +10509,17 @@ Perl_gp_dup(pTHX_ GP *const gp, CLONE_PARAMS *const param)
 MAGIC *
 Perl_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *const param)
 {
-    MAGIC *mgprev = (MAGIC*)NULL;
     MAGIC *mgret = NULL;
+    MAGIC **mgprev_p = &mgret;
 
     PERL_ARGS_ASSERT_MG_DUP;
 
     for (; mg; mg = mg->mg_moremagic) {
        MAGIC *nmg;
        Newxz(nmg, 1, MAGIC);
-       if (mgprev)
-           mgprev->mg_moremagic = nmg;
-       else
-           mgret = nmg;
+       *mgprev_p = nmg;
+       mgprev_p = &(nmg->mg_moremagic);
+
        nmg->mg_virtual = mg->mg_virtual;       /* XXX copy dynamic vtable? */
        nmg->mg_private = mg->mg_private;
        nmg->mg_type    = mg->mg_type;
@@ -10564,7 +10563,6 @@ Perl_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *const param)
        if ((mg->mg_flags & MGf_DUP) && mg->mg_virtual && mg->mg_virtual->svt_dup) {
            CALL_FPTR(nmg->mg_virtual->svt_dup)(aTHX_ nmg, param);
        }
-       mgprev = nmg;
     }
     return mgret;
 }