From 8c3ddf13024d426954986befd742448fa3805788 Mon Sep 17 00:00:00 2001
From: Changpeng Fang <chfang@houghton.(none)>
Date: Tue, 1 Mar 2011 12:50:46 -0800
Subject: [PATCH] Introduce flag -mprefers-avx128 for the vectorizer to generate only 128-bit avx insns.
* config/i386/i386.opt (mprefers-avx128): New flag.
* config/i386/i386.c (ix86_preferred_simd_mode): Prefer 128-bit mode
if the flag -mprefers-avx128 is turned on.
---
gcc/config/i386/i386.c | 4 ++--
gcc/config/i386/i386.opt | 5 +++++
2 files changed, 7 insertions(+), 2 deletions(-)
@@ -34747,9 +34747,9 @@ ix86_preferred_simd_mode (enum machine_mode mode)
switch (mode)
{
case SFmode:
- return TARGET_AVX ? V8SFmode : V4SFmode;
+ return (TARGET_AVX && !flag_prefers_avx128) ? V8SFmode : V4SFmode;
case DFmode:
- return TARGET_AVX ? V4DFmode : V2DFmode;
+ return (TARGET_AVX && !flag_prefers_avx128) ? V4DFmode : V2DFmode;
case DImode:
return V2DImode;
case SImode:
@@ -266,6 +266,11 @@ Target RejectNegative Var(flag_dispatch_scheduler)
Do dispatch scheduling if processor is bdver1 and Haifa scheduling
is selected.
+mprefers-avx128
+Target Report Var(flag_prefers_avx128) Init(0)
+Auto-vectorizer prefers to generate 128-bit AVX instructions instead of 256-bit
+ones.
+
;; ISA support
m32
--
1.6.3.3