refactor pp_list

-move PL_stack_sp and PL_stack_base reads into the branch in which they
 are used, this also removes 1 var from being saved across the function
 call in GIMME, which removes saving and restoring 1 non-vol register
-write SP to PL_stack_sp (PUTBACK) only if it was changed
-POPMARK is mutable, it must execute on all branches

this reduced pp_list's machine code size of the function from 0x58 to
0x53 bytes on VC 2003 -01 32 bits

diff --git a/pp.c b/pp.c
index 04c1f29..51335aa 100644 (file)
--- a/pp.c
+++ b/pp.c
@@ -4847,15 +4847,19 @@ PP(pp_kvhslice)
 
 PP(pp_list)
 {
-    dVAR; dSP; dMARK;
+    dVAR;
+    I32 markidx = POPMARK;
     if (GIMME != G_ARRAY) {
+       SV **mark = PL_stack_base + markidx;
+       dSP;
        if (++MARK <= SP)
            *MARK = *SP;                /* unwanted list, return last item */
        else
            *MARK = &PL_sv_undef;
        SP = MARK;
+       PUTBACK;
     }
-    RETURN;
+    return NORMAL;
 }
 
 PP(pp_lslice)