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[Qemu-devel] [PATCH 5/8] tcg/optimize: Handle known-zeros masks for ANDC
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PATCH 5/8] tcg/optimize: Handle known-zeros masks for ANDC |
Date: |
Fri, 31 Jan 2014 08:47:00 -0600 |
Signed-off-by: Richard Henderson <address@hidden>
---
tcg/optimize.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/tcg/optimize.c b/tcg/optimize.c
index d3b099a..3291a08 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -727,6 +727,17 @@ static TCGArg *tcg_constant_folding(TCGContext *s,
uint16_t *tcg_opc_ptr,
mask = temps[args[1]].mask & mask;
break;
+ CASE_OP_32_64(andc):
+ /* Known-zeros does not imply known-ones. Therefore unless
+ args[2] is constant, we can't infer anything from it. */
+ if (temps[args[2]].state == TCG_TEMP_CONST) {
+ mask = ~temps[args[2]].mask;
+ goto and_const;
+ }
+ /* But we certainly know nothing outside args[1] may be set. */
+ mask = temps[args[1]].mask;
+ break;
+
case INDEX_op_sar_i32:
if (temps[args[2]].state == TCG_TEMP_CONST) {
mask = (int32_t)temps[args[1]].mask >> temps[args[2]].val;
--
1.8.5.3
- [Qemu-devel] [PATCH 0/8] tcg optimization improvements, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 1/8] tcg/optimize: fix known-zero bits for right shift ops, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 2/8] tcg/optimize: fix known-zero bits optimization, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 3/8] tcg/optimize: improve known-zero bits for 32-bit ops, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 4/8] tcg/optimize: add known-zero bits compute for load ops, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 5/8] tcg/optimize: Handle known-zeros masks for ANDC,
Richard Henderson <=
- [Qemu-devel] [PATCH 6/8] tcg/optimize: Simply some logical ops to NOT, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 7/8] tcg/optimize: Optmize ANDC X, Y, Y to MOV X, 0, Richard Henderson, 2014/01/31
- [Qemu-devel] [PATCH 8/8] tcg/optimize: Add more identity simplifications, Richard Henderson, 2014/01/31