[Qemu-devel] [PATCH 4/9] tcg/optimize: do copy propagation for all operations

[Aurelien Jarno]

It is possible to do copy propagation for all operations, even the ones
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.

Signed-off-by: Aurelien Jarno <address@hidden>
---
 tcg/optimize.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 244eb02..a58de3b 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -376,8 +376,15 @@ 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]);
-- 
1.7.10.4