From 4ce7a1e0aaecb220016af9b4f390b76f7fffcce8 Mon Sep 17 00:00:00 2001

From: Aurelien Jarno <aurelien@aurel32.net>

Date: Wed, 19 Sep 2012 21:40:30 +0200

Subject: [PATCH] tcg/optimize: fix end of basic block detection

Commit e31b0a7c050711884ad570fe73df806520953618 fixed copy propagation on

32-bit host by restricting the copy between different types. This was the

wrong fix.

The real problem is that the all temps states should be reset at the end

of a basic block. This was done by adding such operations in the switch,

but brcond2 was forgotten (that's why the crash was only observed on 32-bit

hosts).

Fix that by looking at the TCG_OPF_BB_END instead. We need to keep the case

for op_set_label as temps might be modified through another path.

Cc: Blue Swirl <blauwirbel@gmail.com>

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

---

 tcg/optimize.c | 22 +++++++++-------------

 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c

index 10d9773..9da333c 100644

--- a/tcg/optimize.c

+++ b/tcg/optimize.c

@@ -632,21 +632,17 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,

                 i--;

             }

             break;

-        case INDEX_op_set_label:

-        case INDEX_op_jmp:

-        case INDEX_op_br:

-            memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));

-            for (i = 0; i < def->nb_args; i++) {

-                *gen_args = *args;

-                args++;

-                gen_args++;

-            }

-            break;

         default:

             /* Default case: we do know nothing about operation so no

-               propagation is done.  We only trash output args.  */

-            for (i = 0; i < def->nb_oargs; i++) {

-                reset_temp(args[i], nb_temps, nb_globals);

+               propagation is done.  We trash everything if the operation

+               is the end of a basic block, otherwise we only trash the

+               output args.  */

+            if (def->flags & TCG_OPF_BB_END) {

+                memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));

+            } else {

+                for (i = 0; i < def->nb_oargs; i++) {

+                    reset_temp(args[i], nb_temps, nb_globals);

+                }

             }

             for (i = 0; i < def->nb_args; i++) {

                 gen_args[i] = args[i];

-- 

1.7.12.1