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tcg: Optimize mulu2

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Like add2, do operand ordering, constant folding, and dead operand
elimination.  The latter happens about 15% of all mulu2 during an
x86_64 bios boot.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Richard Henderson 2012-10-02 11:32:30 -07:00 • committed by Aurelien Jarno
parent 1305c451e6
commit 1414968a6a
3 changed files with 47 additions and 0 deletions
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19
tcg/tcg.c
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@ -1338,6 +1338,25 @@ static void tcg_liveness_analysis(TCGContext *s)
}
goto do_not_remove;
case INDEX_op_mulu2_i32:
args -= 4;
nb_iargs = 2;
nb_oargs = 2;
/* Likewise, test for the high part of the operation dead. */
if (dead_temps[args[1]]) {
if (dead_temps[args[0]]) {
goto do_remove;
}
gen_opc_buf[op_index] = op = INDEX_op_mul_i32;
args[1] = args[2];
args[2] = args[3];
assert(gen_opc_buf[op_index + 1] == INDEX_op_nop);
tcg_set_nop(s, gen_opc_buf + op_index + 1, args + 3, 1);
/* Fall through and mark the single-word operation live. */
nb_oargs = 1;
}
goto do_not_remove;
default:
/* XXX: optimize by hardcoding common cases (e.g. triadic ops) */
args -= def->nb_args;