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Re: [Qemu-devel] [PATCH for 1.5] tcg/optimize: fix setcond2 optimization
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH for 1.5] tcg/optimize: fix setcond2 optimization |
Date: |
Wed, 8 May 2013 22:49:31 +0200 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Wed, May 08, 2013 at 10:42:42PM +0200, Aurelien Jarno wrote:
> When setcond2 is rewritten into setcond, the state of the destination
> temp should be reset, so that a copy of the previous value is not
> used instead of the result.
>
> Reported-by: Michael Tokarev <address@hidden>
> Cc: Richard Henderson <address@hidden>
> Signed-off-by: Aurelien Jarno <address@hidden>
> ---
> tcg/optimize.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index 1b6644c..b35868a 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -1057,6 +1057,7 @@ static TCGArg *tcg_constant_folding(TCGContext *s,
> uint16_t *tcg_opc_ptr,
> /* Simplify LT/GE comparisons vs zero to a single compare
> vs the high word of the input. */
> s->gen_opc_buf[op_index] = INDEX_op_setcond_i32;
> + reset_temp(args[0]);
> gen_args[0] = args[0];
> gen_args[1] = args[2];
> gen_args[2] = args[4];
I have just noticed that the problem is there since release 1.3, even if
it appeared more clearly only with commit 7eb0cc85. All 64-bit targets
on 32-bit hosts are possibly affected.
Therefore it should be fixed in the next stable releases. Hence the Cc
to address@hidden
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net