Store GvGP in the SV head union. For all the common lookups [eg GvCV()]

this avoids 1 pointer dereference and the associated risk of a CPU
cache miss. Although this patch looks deceptively small, I fear its
CBV(*) might be rather high.
(* Crack By Volume)

p4raw-id: //depot/perl@27323

1 files changed, 3 insertions, 1 deletions

diff --git a/dump.c b/dump.c
index b63ad5c000..2c6aa23ed2 100644
--- a/dump.c
+++ b/dump.c
@@ -1322,7 +1322,7 @@ Perl_do_sv_dump(pTHX_ I32 level, PerlIO *file, SV *sv, I32 nest, I32 maxnest, bo
 	SvREFCNT_dec(d);
 	return;
     }
-    if (type <= SVt_PVLV) {
+    if (type <= SVt_PVLV && !isGV_with_GP(sv)) {
 	if (SvPVX_const(sv)) {
 	    Perl_dump_indent(aTHX_ level, file,"  PV = 0x%"UVxf" ", PTR2UV(SvPVX_const(sv)));
 	    if (SvOOK(sv))
@@ -1550,6 +1550,8 @@ Perl_do_sv_dump(pTHX_ I32 level, PerlIO *file, SV *sv, I32 nest, I32 maxnest, bo
 	Perl_dump_indent(aTHX_ level, file, "  NAME = \"%s\"\n", GvNAME(sv));
 	Perl_dump_indent(aTHX_ level, file, "  NAMELEN = %"IVdf"\n", (IV)GvNAMELEN(sv));
 	do_hv_dump (level, file, "  GvSTASH", GvSTASH(sv));
+	if (!isGV_with_GP(sv))
+	    break;
 	Perl_dump_indent(aTHX_ level, file, "  GP = 0x%"UVxf"\n", PTR2UV(GvGP(sv)));
 	if (!GvGP(sv))
 	    break;