[llvm] r240310 - [x86] set default reciprocal (division and square root) codegen to match GCC
Sanjay Patel
spatel at rotateright.com
Mon Jun 22 11:29:44 PDT 2015
Author: spatel
Date: Mon Jun 22 13:29:44 2015
New Revision: 240310
URL: http://llvm.org/viewvc/llvm-project?rev=240310&view=rev
Log:
[x86] set default reciprocal (division and square root) codegen to match GCC
D8982 ( checked in at http://reviews.llvm.org/rL239001 ) added command-line
options to allow reciprocal estimate instructions to be used in place of
divisions and square roots.
This patch changes the default settings for x86 targets to allow that recip
codegen (except for scalar division because that breaks too much code) when
using -ffast-math or its equivalent.
This matches GCC behavior for this kind of codegen.
Differential Revision: http://reviews.llvm.org/D10396
Modified:
llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
llvm/trunk/test/CodeGen/X86/recip-fastmath.ll
llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll
Modified: llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetMachine.cpp?rev=240310&r1=240309&r2=240310&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86TargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86TargetMachine.cpp Mon Jun 22 13:29:44 2015
@@ -110,12 +110,15 @@ X86TargetMachine::X86TargetMachine(const
if (Subtarget.isTargetWin64())
this->Options.TrapUnreachable = true;
- // TODO: By default, all reciprocal estimate operations are off because
- // that matches the behavior before TargetRecip was added (except for btver2
- // which used subtarget features to enable this type of codegen).
- // We should change this to match GCC behavior where everything but
- // scalar division estimates are turned on by default with -ffast-math.
- this->Options.Reciprocals.setDefaults("all", false, 1);
+ // By default (and when -ffast-math is on), enable estimate codegen for
+ // everything except scalar division. By default, use 1 refinement step for
+ // all operations. Defaults may be overridden by using command-line options.
+ // Scalar division estimates are disabled because they break too much
+ // real-world code. These defaults match GCC behavior.
+ this->Options.Reciprocals.setDefaults("sqrtf", true, 1);
+ this->Options.Reciprocals.setDefaults("divf", false, 1);
+ this->Options.Reciprocals.setDefaults("vec-sqrtf", true, 1);
+ this->Options.Reciprocals.setDefaults("vec-divf", true, 1);
initAsmInfo();
}
Modified: llvm/trunk/test/CodeGen/X86/recip-fastmath.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/recip-fastmath.ll?rev=240310&r1=240309&r2=240310&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/recip-fastmath.ll (original)
+++ llvm/trunk/test/CodeGen/X86/recip-fastmath.ll Mon Jun 22 13:29:44 2015
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse2 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse2 -recip=!divf,!vec-divf | FileCheck %s --check-prefix=NORECIP
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx -recip=divf,vec-divf | FileCheck %s --check-prefix=RECIP
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx -recip=divf:2,vec-divf:2 | FileCheck %s --check-prefix=REFINE
@@ -14,11 +14,11 @@ define float @reciprocal_estimate(float
%div = fdiv fast float 1.0, %x
ret float %div
-; CHECK-LABEL: reciprocal_estimate:
-; CHECK: movss
-; CHECK-NEXT: divss
-; CHECK-NEXT: movaps
-; CHECK-NEXT: retq
+; NORECIP-LABEL: reciprocal_estimate:
+; NORECIP: movss
+; NORECIP-NEXT: divss
+; NORECIP-NEXT: movaps
+; NORECIP-NEXT: retq
; RECIP-LABEL: reciprocal_estimate:
; RECIP: vrcpss
@@ -45,11 +45,11 @@ define <4 x float> @reciprocal_estimate_
%div = fdiv fast <4 x float> <float 1.0, float 1.0, float 1.0, float 1.0>, %x
ret <4 x float> %div
-; CHECK-LABEL: reciprocal_estimate_v4f32:
-; CHECK: movaps
-; CHECK-NEXT: divps
-; CHECK-NEXT: movaps
-; CHECK-NEXT: retq
+; NORECIP-LABEL: reciprocal_estimate_v4f32:
+; NORECIP: movaps
+; NORECIP-NEXT: divps
+; NORECIP-NEXT: movaps
+; NORECIP-NEXT: retq
; RECIP-LABEL: reciprocal_estimate_v4f32:
; RECIP: vrcpps
@@ -76,14 +76,14 @@ define <8 x float> @reciprocal_estimate_
%div = fdiv fast <8 x float> <float 1.0, float 1.0, float 1.0, float 1.0, float 1.0, float 1.0, float 1.0, float 1.0>, %x
ret <8 x float> %div
-; CHECK-LABEL: reciprocal_estimate_v8f32:
-; CHECK: movaps
-; CHECK: movaps
-; CHECK-NEXT: divps
-; CHECK-NEXT: divps
-; CHECK-NEXT: movaps
-; CHECK-NEXT: movaps
-; CHECK-NEXT: retq
+; NORECIP-LABEL: reciprocal_estimate_v8f32:
+; NORECIP: movaps
+; NORECIP: movaps
+; NORECIP-NEXT: divps
+; NORECIP-NEXT: divps
+; NORECIP-NEXT: movaps
+; NORECIP-NEXT: movaps
+; NORECIP-NEXT: retq
; RECIP-LABEL: reciprocal_estimate_v8f32:
; RECIP: vrcpps
Modified: llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll?rev=240310&r1=240309&r2=240310&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll (original)
+++ llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll Mon Jun 22 13:29:44 2015
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse2 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse2 -recip=!sqrtf,!vec-sqrtf,!divf,!vec-divf | FileCheck %s --check-prefix=NORECIP
; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx -recip=sqrtf,vec-sqrtf | FileCheck %s --check-prefix=ESTIMATE
declare double @__sqrt_finite(double) #0
@@ -10,10 +10,10 @@ declare <8 x float> @llvm.sqrt.v8f32(<8
define double @fd(double %d) #0 {
-; CHECK-LABEL: fd:
-; CHECK: # BB#0:
-; CHECK-NEXT: sqrtsd %xmm0, %xmm0
-; CHECK-NEXT: retq
+; NORECIP-LABEL: fd:
+; NORECIP: # BB#0:
+; NORECIP-NEXT: sqrtsd %xmm0, %xmm0
+; NORECIP-NEXT: retq
;
; ESTIMATE-LABEL: fd:
; ESTIMATE: # BB#0:
@@ -25,10 +25,10 @@ define double @fd(double %d) #0 {
define float @ff(float %f) #0 {
-; CHECK-LABEL: ff:
-; CHECK: # BB#0:
-; CHECK-NEXT: sqrtss %xmm0, %xmm0
-; CHECK-NEXT: retq
+; NORECIP-LABEL: ff:
+; NORECIP: # BB#0:
+; NORECIP-NEXT: sqrtss %xmm0, %xmm0
+; NORECIP-NEXT: retq
;
; ESTIMATE-LABEL: ff:
; ESTIMATE: # BB#0:
@@ -49,11 +49,11 @@ define float @ff(float %f) #0 {
define x86_fp80 @fld(x86_fp80 %ld) #0 {
-; CHECK-LABEL: fld:
-; CHECK: # BB#0:
-; CHECK-NEXT: fldt {{[0-9]+}}(%rsp)
-; CHECK-NEXT: fsqrt
-; CHECK-NEXT: retq
+; NORECIP-LABEL: fld:
+; NORECIP: # BB#0:
+; NORECIP-NEXT: fldt {{[0-9]+}}(%rsp)
+; NORECIP-NEXT: fsqrt
+; NORECIP-NEXT: retq
;
; ESTIMATE-LABEL: fld:
; ESTIMATE: # BB#0:
@@ -67,12 +67,12 @@ define x86_fp80 @fld(x86_fp80 %ld) #0 {
define float @reciprocal_square_root(float %x) #0 {
-; CHECK-LABEL: reciprocal_square_root:
-; CHECK: # BB#0:
-; CHECK-NEXT: sqrtss %xmm0, %xmm1
-; CHECK-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
-; CHECK-NEXT: divss %xmm1, %xmm0
-; CHECK-NEXT: retq
+; NORECIP-LABEL: reciprocal_square_root:
+; NORECIP: # BB#0:
+; NORECIP-NEXT: sqrtss %xmm0, %xmm1
+; NORECIP-NEXT: movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; NORECIP-NEXT: divss %xmm1, %xmm0
+; NORECIP-NEXT: retq
;
; ESTIMATE-LABEL: reciprocal_square_root:
; ESTIMATE: # BB#0:
@@ -89,12 +89,12 @@ define float @reciprocal_square_root(flo
}
define <4 x float> @reciprocal_square_root_v4f32(<4 x float> %x) #0 {
-; CHECK-LABEL: reciprocal_square_root_v4f32:
-; CHECK: # BB#0:
-; CHECK-NEXT: sqrtps %xmm0, %xmm1
-; CHECK-NEXT: movaps {{.*#+}} xmm0 = [1.000000e+00,1.000000e+00,1.000000e+00,1.000000e+00]
-; CHECK-NEXT: divps %xmm1, %xmm0
-; CHECK-NEXT: retq
+; NORECIP-LABEL: reciprocal_square_root_v4f32:
+; NORECIP: # BB#0:
+; NORECIP-NEXT: sqrtps %xmm0, %xmm1
+; NORECIP-NEXT: movaps {{.*#+}} xmm0 = [1.000000e+00,1.000000e+00,1.000000e+00,1.000000e+00]
+; NORECIP-NEXT: divps %xmm1, %xmm0
+; NORECIP-NEXT: retq
;
; ESTIMATE-LABEL: reciprocal_square_root_v4f32:
; ESTIMATE: # BB#0:
@@ -111,15 +111,15 @@ define <4 x float> @reciprocal_square_ro
}
define <8 x float> @reciprocal_square_root_v8f32(<8 x float> %x) #0 {
-; CHECK-LABEL: reciprocal_square_root_v8f32:
-; CHECK: # BB#0:
-; CHECK-NEXT: sqrtps %xmm1, %xmm2
-; CHECK-NEXT: sqrtps %xmm0, %xmm3
-; CHECK-NEXT: movaps {{.*#+}} xmm1 = [1.000000e+00,1.000000e+00,1.000000e+00,1.000000e+00]
-; CHECK-NEXT: movaps %xmm1, %xmm0
-; CHECK-NEXT: divps %xmm3, %xmm0
-; CHECK-NEXT: divps %xmm2, %xmm1
-; CHECK-NEXT: retq
+; NORECIP-LABEL: reciprocal_square_root_v8f32:
+; NORECIP: # BB#0:
+; NORECIP-NEXT: sqrtps %xmm1, %xmm2
+; NORECIP-NEXT: sqrtps %xmm0, %xmm3
+; NORECIP-NEXT: movaps {{.*#+}} xmm1 = [1.000000e+00,1.000000e+00,1.000000e+00,1.000000e+00]
+; NORECIP-NEXT: movaps %xmm1, %xmm0
+; NORECIP-NEXT: divps %xmm3, %xmm0
+; NORECIP-NEXT: divps %xmm2, %xmm1
+; NORECIP-NEXT: retq
;
; ESTIMATE-LABEL: reciprocal_square_root_v8f32:
; ESTIMATE: # BB#0:
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