qemu/0021-tcg-optimize-simplify-shift-rot-r-0-a-movi-r-0-cases.patch
2012-10-28 14:05:07 -04:00

49 lines
1.5 KiB
Diff

From bbed332c7ad12e9885d3f457f366fa0b29445dcd Mon Sep 17 00:00:00 2001
From: Aurelien Jarno <aurelien@aurel32.net>
Date: Thu, 6 Sep 2012 16:47:14 +0200
Subject: [PATCH] tcg/optimize: simplify shift/rot r, 0, a => movi r, 0 cases
shift/rot r, 0, a is equivalent to movi r, 0.
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
tcg/optimize.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index c12cb2b..1698ba3 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -322,6 +322,26 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
break;
}
+ /* Simplify expressions for "shift/rot r, 0, a => movi r, 0" */
+ switch (op) {
+ CASE_OP_32_64(shl):
+ CASE_OP_32_64(shr):
+ CASE_OP_32_64(sar):
+ CASE_OP_32_64(rotl):
+ CASE_OP_32_64(rotr):
+ if (temps[args[1]].state == TCG_TEMP_CONST
+ && temps[args[1]].val == 0) {
+ gen_opc_buf[op_index] = op_to_movi(op);
+ tcg_opt_gen_movi(gen_args, args[0], 0, nb_temps, nb_globals);
+ args += 3;
+ gen_args += 2;
+ continue;
+ }
+ break;
+ default:
+ break;
+ }
+
/* Simplify expression for "op r, a, 0 => mov r, a" cases */
switch (op) {
CASE_OP_32_64(add):
--
1.7.12.1