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tcg/optimize: swap brcond/setcond arguments when possible

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brcond and setcond ops are not commutative, but it's easy to compute the
new condition after swapping the arguments. Try to always put the constant
argument in second position like for commutative ops, to help backends to
generate better code.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2012-09-06 16:47:14 +02:00
parent 01ee5282ea
commit 65a7cce17d
1 changed files with 18 additions and 0 deletions
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18
tcg/optimize.c
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@ -318,6 +318,24 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
args[2] = tmp;
}
break;
CASE_OP_32_64(brcond):
if (temps[args[0]].state == TCG_TEMP_CONST
&& temps[args[1]].state != TCG_TEMP_CONST) {
tmp = args[0];
args[0] = args[1];
args[1] = tmp;
args[2] = tcg_swap_cond(args[2]);
}
break;
CASE_OP_32_64(setcond):
if (temps[args[1]].state == TCG_TEMP_CONST
&& temps[args[2]].state != TCG_TEMP_CONST) {
tmp = args[1];
args[1] = args[2];
args[2] = tmp;
args[3] = tcg_swap_cond(args[3]);
}
break;
default:
break;
}