[llvm] r263717 - [X86][SSE] Simplified blend-with-zero combining
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 17 08:59:37 PDT 2016
Author: rksimon
Date: Thu Mar 17 10:59:36 2016
New Revision: 263717
URL: http://llvm.org/viewvc/llvm-project?rev=263717&view=rev
Log:
[X86][SSE] Simplified blend-with-zero combining
We were being too aggressive in trying to combine a shuffle into a blend-with-zero pattern, often resulting in a endless loop of contrasting combines
This patch stops the combine if we already have a blend in place (means we miss some domain corrections)
Modified:
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/CodeGen/X86/merge-consecutive-loads-256.ll
llvm/trunk/test/CodeGen/X86/vector-shuffle-combining.ll
llvm/trunk/test/CodeGen/X86/vector-zext.ll
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=263717&r1=263716&r2=263717&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Mar 17 10:59:36 2016
@@ -1919,7 +1919,7 @@ EVT X86TargetLowering::getSetCCResultTyp
EVT LegalVT = getTypeToTransformTo(Context, VT);
EltVT = LegalVT.getVectorElementType().getSimpleVT();
}
-
+
if (Subtarget.hasVLX() && EltVT.getSizeInBits() >= 32)
switch(NumElts) {
case 2: return MVT::v2i1;
@@ -23958,23 +23958,22 @@ static bool combineX86ShuffleChain(SDVal
unsigned ShuffleSize = ShuffleVT.getVectorNumElements();
unsigned MaskRatio = ShuffleSize / Mask.size();
+ if (Depth == 1 && Root.getOpcode() == X86ISD::BLENDI)
+ return false;
+
for (unsigned i = 0; i != ShuffleSize; ++i)
if (Mask[i / MaskRatio] < 0)
BlendMask |= 1u << i;
- if (Depth != 1 || RootVT != ShuffleVT ||
- Root.getOpcode() != X86ISD::BLENDI ||
- Root->getConstantOperandVal(2) != BlendMask) {
- SDValue Zero = getZeroVector(ShuffleVT, Subtarget, DAG, DL);
- Res = DAG.getBitcast(ShuffleVT, Input);
- DCI.AddToWorklist(Res.getNode());
- Res = DAG.getNode(X86ISD::BLENDI, DL, ShuffleVT, Res, Zero,
- DAG.getConstant(BlendMask, DL, MVT::i8));
- DCI.AddToWorklist(Res.getNode());
- DCI.CombineTo(Root.getNode(), DAG.getBitcast(RootVT, Res),
- /*AddTo*/ true);
- return true;
- }
+ SDValue Zero = getZeroVector(ShuffleVT, Subtarget, DAG, DL);
+ Res = DAG.getBitcast(ShuffleVT, Input);
+ DCI.AddToWorklist(Res.getNode());
+ Res = DAG.getNode(X86ISD::BLENDI, DL, ShuffleVT, Res, Zero,
+ DAG.getConstant(BlendMask, DL, MVT::i8));
+ DCI.AddToWorklist(Res.getNode());
+ DCI.CombineTo(Root.getNode(), DAG.getBitcast(RootVT, Res),
+ /*AddTo*/ true);
+ return true;
}
}
Modified: llvm/trunk/test/CodeGen/X86/merge-consecutive-loads-256.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/merge-consecutive-loads-256.ll?rev=263717&r1=263716&r2=263717&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/merge-consecutive-loads-256.ll (original)
+++ llvm/trunk/test/CodeGen/X86/merge-consecutive-loads-256.ll Thu Mar 17 10:59:36 2016
@@ -278,8 +278,8 @@ define <8 x float> @merge_8f32_2f32_23z5
; X32-AVX-LABEL: merge_8f32_2f32_23z5:
; X32-AVX: # BB#0:
; X32-AVX-NEXT: movl {{[0-9]+}}(%esp), %eax
-; X32-AVX-NEXT: vxorps %ymm0, %ymm0, %ymm0
-; X32-AVX-NEXT: vblendps {{.*#+}} ymm0 = mem[0,1,2,3],ymm0[4,5],mem[6,7]
+; X32-AVX-NEXT: vxorpd %ymm0, %ymm0, %ymm0
+; X32-AVX-NEXT: vblendpd {{.*#+}} ymm0 = mem[0,1],ymm0[2],mem[3]
; X32-AVX-NEXT: retl
%ptr0 = getelementptr inbounds <2 x float>, <2 x float>* %ptr, i64 2
%ptr1 = getelementptr inbounds <2 x float>, <2 x float>* %ptr, i64 3
Modified: llvm/trunk/test/CodeGen/X86/vector-shuffle-combining.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-shuffle-combining.ll?rev=263717&r1=263716&r2=263717&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vector-shuffle-combining.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vector-shuffle-combining.ll Thu Mar 17 10:59:36 2016
@@ -2819,6 +2819,50 @@ define <4 x float> @combine_insertps4(<4
ret <4 x float> %d
}
+; FIXME: Failed to recognise that the VMOVSD has already zero'd the upper element
+define void @combine_scalar_load_with_blend_with_zero(double* %a0, <4 x float>* %a1) {
+; SSE2-LABEL: combine_scalar_load_with_blend_with_zero:
+; SSE2: # BB#0:
+; SSE2-NEXT: movsd {{.*#+}} xmm0 = mem[0],zero
+; SSE2-NEXT: xorps %xmm1, %xmm1
+; SSE2-NEXT: shufps {{.*#+}} xmm1 = xmm1[0,0],xmm0[3,0]
+; SSE2-NEXT: shufps {{.*#+}} xmm0 = xmm0[0,1],xmm1[0,2]
+; SSE2-NEXT: movaps %xmm0, (%rsi)
+; SSE2-NEXT: retq
+;
+; SSSE3-LABEL: combine_scalar_load_with_blend_with_zero:
+; SSSE3: # BB#0:
+; SSSE3-NEXT: movsd {{.*#+}} xmm0 = mem[0],zero
+; SSSE3-NEXT: xorps %xmm1, %xmm1
+; SSSE3-NEXT: shufps {{.*#+}} xmm1 = xmm1[0,0],xmm0[3,0]
+; SSSE3-NEXT: shufps {{.*#+}} xmm0 = xmm0[0,1],xmm1[0,2]
+; SSSE3-NEXT: movaps %xmm0, (%rsi)
+; SSSE3-NEXT: retq
+;
+; SSE41-LABEL: combine_scalar_load_with_blend_with_zero:
+; SSE41: # BB#0:
+; SSE41-NEXT: movsd {{.*#+}} xmm0 = mem[0],zero
+; SSE41-NEXT: xorpd %xmm1, %xmm1
+; SSE41-NEXT: blendpd {{.*#+}} xmm1 = xmm0[0],xmm1[1]
+; SSE41-NEXT: movapd %xmm1, (%rsi)
+; SSE41-NEXT: retq
+;
+; AVX-LABEL: combine_scalar_load_with_blend_with_zero:
+; AVX: # BB#0:
+; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
+; AVX-NEXT: vxorpd %xmm1, %xmm1, %xmm1
+; AVX-NEXT: vblendpd {{.*#+}} xmm0 = xmm0[0],xmm1[1]
+; AVX-NEXT: vmovapd %xmm0, (%rsi)
+; AVX-NEXT: retq
+ %1 = load double, double* %a0, align 8
+ %2 = insertelement <2 x double> undef, double %1, i32 0
+ %3 = insertelement <2 x double> %2, double 0.000000e+00, i32 1
+ %4 = bitcast <2 x double> %3 to <4 x float>
+ %5 = shufflevector <4 x float> %4, <4 x float> <float 0.000000e+00, float undef, float undef, float undef>, <4 x i32> <i32 0, i32 1, i32 4, i32 3>
+ store <4 x float> %5, <4 x float>* %a1, align 16
+ ret void
+}
+
define <4 x float> @PR22377(<4 x float> %a, <4 x float> %b) {
; SSE-LABEL: PR22377:
; SSE: # BB#0: # %entry
Modified: llvm/trunk/test/CodeGen/X86/vector-zext.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-zext.ll?rev=263717&r1=263716&r2=263717&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vector-zext.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vector-zext.ll Thu Mar 17 10:59:36 2016
@@ -1151,8 +1151,8 @@ define <4 x i64> @shuf_zext_4i32_to_4i64
; AVX1-LABEL: shuf_zext_4i32_to_4i64:
; AVX1: # BB#0: # %entry
; AVX1-NEXT: vinsertps {{.*#+}} xmm1 = xmm0[0],zero,xmm0[1],zero
-; AVX1-NEXT: vpxor %xmm2, %xmm2, %xmm2
-; AVX1-NEXT: vpblendw {{.*#+}} xmm0 = xmm2[0,1,2,3],xmm0[4,5,6,7]
+; AVX1-NEXT: vxorpd %xmm2, %xmm2, %xmm2
+; AVX1-NEXT: vblendpd {{.*#+}} xmm0 = xmm2[0],xmm0[1]
; AVX1-NEXT: vpermilps {{.*#+}} xmm0 = xmm0[2,0,3,0]
; AVX1-NEXT: vinsertf128 $1, %xmm0, %ymm1, %ymm0
; AVX1-NEXT: retq
@@ -1581,8 +1581,8 @@ define <4 x i64> @shuf_zext_4i32_to_4i64
; AVX1-LABEL: shuf_zext_4i32_to_4i64_offset1:
; AVX1: # BB#0: # %entry
; AVX1-NEXT: vinsertps {{.*#+}} xmm1 = xmm0[3],zero,zero,zero
-; AVX1-NEXT: vpxor %xmm2, %xmm2, %xmm2
-; AVX1-NEXT: vpblendw {{.*#+}} xmm0 = xmm2[0,1,2,3],xmm0[4,5],xmm2[6,7]
+; AVX1-NEXT: vxorps %xmm2, %xmm2, %xmm2
+; AVX1-NEXT: vblendps {{.*#+}} xmm0 = xmm2[0,1],xmm0[2],xmm2[3]
; AVX1-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm0
; AVX1-NEXT: retq
;
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