don't create a copy of keys if it's not LVALUE context

Making another copy slows things down. We can avoid it
if aassign is not expected to return LVALUEs.

diff --git a/pp_hot.c b/pp_hot.c
index cd036dd..76a9e43 100644 (file)
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -992,9 +992,12 @@ PP(pp_aassign)
     HV *hash;
     I32 i;
     int magic;
+    U32 lval = 0;
 
     PL_delaymagic = DM_DELAY;          /* catch simultaneous items */
     gimme = GIMME_V;
+    if (gimme == G_ARRAY)
+        lval = PL_op->op_flags & OPf_MOD || LVRET;
 
     /* If there's a common identifier on both sides we have to take
      * special care that assigning the identifier on the left doesn't
@@ -1093,7 +1096,7 @@ PP(pp_aassign)
                while (relem < lastrelem+odd) { /* gobble up all the rest */
                    HE *didstore;
                     assert(*relem);
-                   sv = gimme == G_ARRAY ? sv_mortalcopy(*relem) : *relem;
+                   sv = lval ? sv_mortalcopy(*relem) : *relem;
                    relem++;
                     assert(*relem);
                    tmpstr = sv_mortalcopy( *relem++ ); /* value */