|
 |
5544c1 |
From a0b71ad6a3f8aeb8b5ea6d112a7afeadc7c004a4 Mon Sep 17 00:00:00 2001
|
|
|
5544c1 |
From: Aurelien Jarno <aurelien@aurel32.net>
|
|
|
5544c1 |
Date: Wed, 19 Sep 2012 22:00:22 +0200
|
|
|
5544c1 |
Subject: [PATCH] tcg/optimize: prefer the "op a, a, b" form for commutative
|
|
|
5544c1 |
ops
|
|
|
5544c1 |
|
|
|
5544c1 |
The "op a, a, b" form is better handled on non-RISC host than the "op
|
|
|
5544c1 |
a, b, a" form, so swap the arguments to this form when possible, and
|
|
|
5544c1 |
when b is not a constant.
|
|
|
5544c1 |
|
|
|
5544c1 |
This reduces the number of generated instructions by a tiny bit.
|
|
|
5544c1 |
|
|
|
5544c1 |
Reviewed-by: Richard Henderson <rth@twiddle.net>
|
|
|
5544c1 |
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
|
|
|
5544c1 |
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
|
|
|
5544c1 |
---
|
|
|
5544c1 |
tcg/optimize.c | 5 ++++-
|
|
|
5544c1 |
1 file changed, 4 insertions(+), 1 deletion(-)
|
|
|
5544c1 |
|
|
|
5544c1 |
diff --git a/tcg/optimize.c b/tcg/optimize.c
|
|
|
5544c1 |
index abe016a..c8ae50b 100644
|
|
|
5544c1 |
--- a/tcg/optimize.c
|
|
|
5544c1 |
+++ b/tcg/optimize.c
|
|
|
5544c1 |
@@ -434,7 +434,10 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
|
|
|
5544c1 |
CASE_OP_32_64(eqv):
|
|
|
5544c1 |
CASE_OP_32_64(nand):
|
|
|
5544c1 |
CASE_OP_32_64(nor):
|
|
|
5544c1 |
- if (temps[args[1]].state == TCG_TEMP_CONST) {
|
|
|
5544c1 |
+ /* Prefer the constant in second argument, and then the form
|
|
|
5544c1 |
+ op a, a, b, which is better handled on non-RISC hosts. */
|
|
|
5544c1 |
+ if (temps[args[1]].state == TCG_TEMP_CONST || (args[0] == args[2]
|
|
|
5544c1 |
+ && temps[args[2]].state != TCG_TEMP_CONST)) {
|
|
|
5544c1 |
tmp = args[1];
|
|
|
5544c1 |
args[1] = args[2];
|
|
|
5544c1 |
args[2] = tmp;
|
|
|
5544c1 |
--
|
|
|
5544c1 |
1.7.12.1
|
|
|
5544c1 |
|