s390: rearrange temp moves in s390_expand_cs_hqi

[Richard Henderson]

In the same vein as your CAS boolean output patch, if we rearrange the
copies here we can get the combined compare-and-branch insn for the z10.
I see that the z196 prefers not to use those, but the number of insns
in that case remains the same, merely in a different order.

Can you please test with --with-arch=z10?


r~



        * config/s390/s390.c (s390_expand_cs_hqi): Copy val to a temp before
        performing the compare for the restart loop.

commit 7c855c60ce06b2d9ad0774877ffab38a8cc48f2d
Author: Richard Henderson <r...@redhat.com>
Date:   Mon Aug 6 15:08:18 2012 -0700

    s390: Rearrange temporary moves for use of CRJ

diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 20a2db6..6b75dad 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -4821,7 +4821,7 @@ s390_expand_cs_hqi (enum machine_mode mode, rtx btarget, 
rtx vtarget, rtx mem,
                    rtx cmp, rtx new_rtx, bool is_weak)
 {
   struct alignment_context ac;
-  rtx cmpv, newv, val, resv, cc, seq0, seq1, seq2, seq3;
+  rtx cmpv, newv, val, cc, seq0, seq1, seq2, seq3;
   rtx res = gen_reg_rtx (SImode);
   rtx csloop = NULL, csend = NULL;
 
@@ -4869,14 +4869,18 @@ s390_expand_cs_hqi (enum machine_mode mode, rtx 
btarget, rtx vtarget, rtx mem,
     emit_insn (gen_cstorecc4 (btarget, cc, XEXP (cc, 0), XEXP (cc, 1)));
   else
     {
+      rtx tmp;
+
       /* Jump to end if we're done (likely?).  */
       s390_emit_jump (csend, cc);
 
-      /* Check for changes outside mode, and loop internal if so.  */
-      resv = expand_simple_binop (SImode, AND, res, ac.modemaski,
-                                 NULL_RTX, 1, OPTAB_DIRECT);
-      cc = s390_emit_compare (NE, resv, val);
-      emit_move_insn (val, resv);
+      /* Check for changes outside mode, and loop internal if so.
+        Arrange the moves so that the compare is adjacent to the
+        branch so that we can generate CRJ.  */
+      tmp = copy_to_reg (val);
+      force_expand_binop (SImode, and_optab, res, ac.modemaski, val,
+                         1, OPTAB_DIRECT);
+      cc = s390_emit_compare (NE, val, tmp);
       s390_emit_jump (csloop, cc);
 
       /* Failed.  */