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Blame 0046-tcg-optimize-fix-end-of-basic-block-detection.patch

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From 4ce7a1e0aaecb220016af9b4f390b76f7fffcce8 Mon Sep 17 00:00:00 2001
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From: Aurelien Jarno <aurelien@aurel32.net>
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Date: Wed, 19 Sep 2012 21:40:30 +0200
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Subject: [PATCH] tcg/optimize: fix end of basic block detection
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Commit e31b0a7c050711884ad570fe73df806520953618 fixed copy propagation on
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32-bit host by restricting the copy between different types. This was the
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wrong fix.
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The real problem is that the all temps states should be reset at the end
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of a basic block. This was done by adding such operations in the switch,
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but brcond2 was forgotten (that's why the crash was only observed on 32-bit
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hosts).
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Fix that by looking at the TCG_OPF_BB_END instead. We need to keep the case
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for op_set_label as temps might be modified through another path.
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Cc: Blue Swirl <blauwirbel@gmail.com>
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Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
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Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
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---
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 tcg/optimize.c | 22 +++++++++-------------
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 1 file changed, 9 insertions(+), 13 deletions(-)
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diff --git a/tcg/optimize.c b/tcg/optimize.c
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index 10d9773..9da333c 100644
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--- a/tcg/optimize.c
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+++ b/tcg/optimize.c
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@@ -632,21 +632,17 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
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                 i--;
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             }
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             break;
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-        case INDEX_op_set_label:
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-        case INDEX_op_jmp:
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-        case INDEX_op_br:
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-            memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
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-            for (i = 0; i < def->nb_args; i++) {
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-                *gen_args = *args;
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-                args++;
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-                gen_args++;
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-            }
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-            break;
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         default:
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             /* Default case: we do know nothing about operation so no
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-               propagation is done.  We only trash output args.  */
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-            for (i = 0; i < def->nb_oargs; i++) {
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-                reset_temp(args[i], nb_temps, nb_globals);
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+               propagation is done.  We trash everything if the operation
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+               is the end of a basic block, otherwise we only trash the
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+               output args.  */
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+            if (def->flags & TCG_OPF_BB_END) {
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+                memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
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+            } else {
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+                for (i = 0; i < def->nb_oargs; i++) {
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+                    reset_temp(args[i], nb_temps, nb_globals);
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+                }
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             }
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             for (i = 0; i < def->nb_args; i++) {
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                 gen_args[i] = args[i];
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-- 
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1.7.12.1
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