(UN)LIKELY branch prediction hints in a few strategic places

This adds branch prediction hints to a few strategic places such as
growing stack or strings, some exception handling, and a few hot
functions such as sv_upgrade.

This is not exhaustive by any means.

1 files changed, 3 insertions, 3 deletions

diff --git a/inline.h b/inline.h
index 6b5f93c777..6cdfe9f178 100644
--- a/inline.h
+++ b/inline.h
@@ -46,7 +46,7 @@ S_ReANY(const REGEXP * const re)
 PERL_STATIC_INLINE SV *
 S_SvREFCNT_inc(SV *sv)
 {
-    if (sv)
+    if (LIKELY(sv != NULL))
 	SvREFCNT(sv)++;
     return sv;
 }
@@ -59,13 +59,13 @@ S_SvREFCNT_inc_NN(SV *sv)
 PERL_STATIC_INLINE void
 S_SvREFCNT_inc_void(SV *sv)
 {
-    if (sv)
+    if (LIKELY(sv != NULL))
 	SvREFCNT(sv)++;
 }
 PERL_STATIC_INLINE void
 S_SvREFCNT_dec(pTHX_ SV *sv)
 {
-    if (sv) {
+    if (LIKELY(sv != NULL)) {
 	U32 rc = SvREFCNT(sv);
 	if (rc > 1)
 	    SvREFCNT(sv) = rc - 1;