avoid clearing @_ at all for faster subroutine calls; fix bugs

in passing around references to @_, eg C<sub foo { \@_ }>; add
tests for the same

p4raw-id: //depot/perl@4195

1 files changed, 1 insertions, 5 deletions

diff --git a/pp_hot.c b/pp_hot.c
index e75ec30258..df5e0624d9 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -2522,11 +2522,7 @@ try_autoload:
 	    			  "%p entersub preparing @_\n", thr));
 #endif
 	    av = (AV*)PL_curpad[0];
-	    if (AvREAL(av)) {
-		av_clear(av);
-		AvREAL_off(av);
-		AvREIFY_on(av);
-	    }
+	    assert(!AvREAL(av));
 #ifndef USE_THREADS
 	    cx->blk_sub.savearray = GvAV(PL_defgv);
 	    GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av);