qemu/0071-tcg-optimize-do-copy-propagation-for-all-operations.patch

From 7c1a67bb734f364ea0643b549e030f04d4eed798 Mon Sep 17 00:00:00 2001
From: Aurelien Jarno <aurelien@aurel32.net>
Date: Tue, 11 Sep 2012 16:18:49 +0200
Subject: [PATCH] tcg/optimize: do copy propagation for all operations

It is possible to due copy propagation for all operations, even the one
that have side effects or clobber arguments (it only concerns input
arguments). That said, the call operation should be handled differently
due to the variable number of arguments.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 tcg/optimize.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 1904b39..aeb2225 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -378,8 +378,15 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
         op = gen_opc_buf[op_index];
         def = &tcg_op_defs[op];
         /* Do copy propagation */
-        if (!(def->flags & (TCG_OPF_CALL_CLOBBER | TCG_OPF_SIDE_EFFECTS))) {
-            assert(op != INDEX_op_call);
+        if (op == INDEX_op_call) {
+            int nb_oargs = args[0] >> 16;
+            int nb_iargs = args[0] & 0xffff;
+            for (i = nb_oargs + 1; i < nb_oargs + nb_iargs + 1; i++) {
+                if (temps[args[i]].state == TCG_TEMP_COPY) {
+                    args[i] = find_better_copy(s, args[i]);
+                }
+            }
+        } else {
             for (i = def->nb_oargs; i < def->nb_oargs + def->nb_iargs; i++) {
                 if (temps[args[i]].state == TCG_TEMP_COPY) {
                     args[i] = find_better_copy(s, args[i]);
-- 
1.8.0.2