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SROA: Generate selects instead of shuffles when blending values becau…
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…se this is the cannonical form.

Shuffles are more difficult to lower and we usually don't touch them, while we do optimize selects more often.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180875 91177308-0d34-0410-b5e6-96231b3b80d8
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@nadavrot
nadavrot committed May 1, 2013
1 parent f0b0755 commit fee6969
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Showing 2 changed files with 20 additions and 22 deletions.
14 changes: 6 additions & 8 deletions lib/Transforms/Scalar/SROA.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2322,17 +2322,15 @@ static Value *insertVector(IRBuilderTy &IRB, Value *Old, Value *V,
V = IRB.CreateShuffleVector(V, UndefValue::get(V->getType()),
ConstantVector::get(Mask),
Name + ".expand");
DEBUG(dbgs() << " shuffle1: " << *V << "\n");
DEBUG(dbgs() << " shuffle: " << *V << "\n");

Mask.clear();
for (unsigned i = 0; i != VecTy->getNumElements(); ++i)
if (i >= BeginIndex && i < EndIndex)
Mask.push_back(IRB.getInt32(i));
else
Mask.push_back(IRB.getInt32(i + VecTy->getNumElements()));
V = IRB.CreateShuffleVector(V, Old, ConstantVector::get(Mask),
Name + "insert");
DEBUG(dbgs() << " shuffle2: " << *V << "\n");
Mask.push_back(IRB.getInt1(i >= BeginIndex && i < EndIndex));

V = IRB.CreateSelect(ConstantVector::get(Mask), V, Old, Name + "blend");

DEBUG(dbgs() << " blend: " << *V << "\n");
return V;
}

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28 changes: 14 additions & 14 deletions test/Transforms/SROA/vector-promotion.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -224,26 +224,26 @@ entry:
%a.cast0 = bitcast i32* %a.gep0 to <2 x i32>*
store <2 x i32> <i32 0, i32 0>, <2 x i32>* %a.cast0
; CHECK-NOT: store
; CHECK: %[[insert1:.*]] = shufflevector <4 x i32> <i32 0, i32 0, i32 undef, i32 undef>, <4 x i32> undef, <4 x i32> <i32 0, i32 1, {{.*}}>
; CHECK: select <4 x i1> <i1 true, i1 true, i1 false, i1 false>

%a.gep1 = getelementptr <4 x i32>* %a, i32 0, i32 1
%a.cast1 = bitcast i32* %a.gep1 to <2 x i32>*
store <2 x i32> <i32 1, i32 1>, <2 x i32>* %a.cast1
; CHECK-NEXT: %[[insert2:.*]] = shufflevector <4 x i32> <i32 undef, i32 1, i32 1, i32 undef>, <4 x i32> %[[insert1]], <4 x i32> <i32 4, i32 1, i32 2, {{.*}}>
; CHECK-NEXT: select <4 x i1> <i1 false, i1 true, i1 true, i1 false>

%a.gep2 = getelementptr <4 x i32>* %a, i32 0, i32 2
%a.cast2 = bitcast i32* %a.gep2 to <2 x i32>*
store <2 x i32> <i32 2, i32 2>, <2 x i32>* %a.cast2
; CHECK-NEXT: %[[insert3:.*]] = shufflevector <4 x i32> <i32 undef, i32 undef, i32 2, i32 2>, <4 x i32> %[[insert2]], <4 x i32> <i32 4, i32 5, i32 2, i32 3>
; CHECK-NEXT: select <4 x i1> <i1 false, i1 false, i1 true, i1 true>

%a.gep3 = getelementptr <4 x i32>* %a, i32 0, i32 3
store i32 3, i32* %a.gep3
; CHECK-NEXT: %[[insert4:.*]] = insertelement <4 x i32> %[[insert3]], i32 3, i32 3
; CHECK-NEXT: insertelement <4 x i32>

%ret = load <4 x i32>* %a

ret <4 x i32> %ret
; CHECK-NEXT: ret <4 x i32> %[[insert4]]
; CHECK-NEXT: ret <4 x i32>
}

define <4 x i32> @test_subvec_load() {
Expand Down Expand Up @@ -291,27 +291,27 @@ entry:
%a.cast0 = bitcast float* %a.gep0 to i8*
call void @llvm.memset.p0i8.i32(i8* %a.cast0, i8 0, i32 8, i32 0, i1 false)
; CHECK-NOT: store
; CHECK: %[[insert1:.*]] = shufflevector <4 x float> <float 0.000000e+00, float 0.000000e+00, float undef, float undef>, <4 x float> undef, <4 x i32> <i32 0, i32 1, {{.*}}>
; CHECK: select <4 x i1> <i1 true, i1 true, i1 false, i1 false>

%a.gep1 = getelementptr <4 x float>* %a, i32 0, i32 1
%a.cast1 = bitcast float* %a.gep1 to i8*
call void @llvm.memset.p0i8.i32(i8* %a.cast1, i8 1, i32 8, i32 0, i1 false)
; CHECK-NEXT: %[[insert2:.*]] = shufflevector <4 x float> <float undef, float 0x3820202020000000, float 0x3820202020000000, float undef>, <4 x float> %[[insert1]], <4 x i32> <i32 4, i32 1, i32 2, {{.*}}>
; CHECK-NEXT: select <4 x i1> <i1 false, i1 true, i1 true, i1 false>

%a.gep2 = getelementptr <4 x float>* %a, i32 0, i32 2
%a.cast2 = bitcast float* %a.gep2 to i8*
call void @llvm.memset.p0i8.i32(i8* %a.cast2, i8 3, i32 8, i32 0, i1 false)
; CHECK-NEXT: %[[insert3:.*]] = shufflevector <4 x float> <float undef, float undef, float 0x3860606060000000, float 0x3860606060000000>, <4 x float> %[[insert2]], <4 x i32> <i32 4, i32 5, i32 2, i32 3>
; CHECK-NEXT: select <4 x i1> <i1 false, i1 false, i1 true, i1 true>

%a.gep3 = getelementptr <4 x float>* %a, i32 0, i32 3
%a.cast3 = bitcast float* %a.gep3 to i8*
call void @llvm.memset.p0i8.i32(i8* %a.cast3, i8 7, i32 4, i32 0, i1 false)
; CHECK-NEXT: %[[insert4:.*]] = insertelement <4 x float> %[[insert3]], float 0x38E0E0E0E0000000, i32 3
; CHECK-NEXT: insertelement <4 x float>

%ret = load <4 x float>* %a

ret <4 x float> %ret
; CHECK-NEXT: ret <4 x float> %[[insert4]]
; CHECK-NEXT: ret <4 x float>
}

define <4 x float> @test_subvec_memcpy(i8* %x, i8* %y, i8* %z, i8* %f, i8* %out) {
Expand All @@ -326,30 +326,30 @@ entry:
; CHECK: %[[xptr:.*]] = bitcast i8* %x to <2 x float>*
; CHECK-NEXT: %[[x:.*]] = load <2 x float>* %[[xptr]]
; CHECK-NEXT: %[[expand_x:.*]] = shufflevector <2 x float> %[[x]], <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
; CHECK-NEXT: %[[insert_x:.*]] = shufflevector <4 x float> %[[expand_x]], <4 x float> undef, <4 x i32> <i32 0, i32 1, {{.*}}>
; CHECK-NEXT: select <4 x i1> <i1 true, i1 true, i1 false, i1 false>

%a.gep1 = getelementptr <4 x float>* %a, i32 0, i32 1
%a.cast1 = bitcast float* %a.gep1 to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a.cast1, i8* %y, i32 8, i32 0, i1 false)
; CHECK-NEXT: %[[yptr:.*]] = bitcast i8* %y to <2 x float>*
; CHECK-NEXT: %[[y:.*]] = load <2 x float>* %[[yptr]]
; CHECK-NEXT: %[[expand_y:.*]] = shufflevector <2 x float> %[[y]], <2 x float> undef, <4 x i32> <i32 undef, i32 0, i32 1, i32 undef>
; CHECK-NEXT: %[[insert_y:.*]] = shufflevector <4 x float> %[[expand_y]], <4 x float> %[[insert_x]], <4 x i32> <i32 4, i32 1, i32 2, {{.*}}>
; CHECK-NEXT: select <4 x i1> <i1 false, i1 true, i1 true, i1 false>

%a.gep2 = getelementptr <4 x float>* %a, i32 0, i32 2
%a.cast2 = bitcast float* %a.gep2 to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a.cast2, i8* %z, i32 8, i32 0, i1 false)
; CHECK-NEXT: %[[zptr:.*]] = bitcast i8* %z to <2 x float>*
; CHECK-NEXT: %[[z:.*]] = load <2 x float>* %[[zptr]]
; CHECK-NEXT: %[[expand_z:.*]] = shufflevector <2 x float> %[[z]], <2 x float> undef, <4 x i32> <i32 undef, i32 undef, i32 0, i32 1>
; CHECK-NEXT: %[[insert_z:.*]] = shufflevector <4 x float> %[[expand_z]], <4 x float> %[[insert_y]], <4 x i32> <i32 4, i32 5, i32 2, i32 3>
; CHECK-NEXT: select <4 x i1> <i1 false, i1 false, i1 true, i1 true>

%a.gep3 = getelementptr <4 x float>* %a, i32 0, i32 3
%a.cast3 = bitcast float* %a.gep3 to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a.cast3, i8* %f, i32 4, i32 0, i1 false)
; CHECK-NEXT: %[[fptr:.*]] = bitcast i8* %f to float*
; CHECK-NEXT: %[[f:.*]] = load float* %[[fptr]]
; CHECK-NEXT: %[[insert_f:.*]] = insertelement <4 x float> %[[insert_z]], float %[[f]], i32 3
; CHECK-NEXT: %[[insert_f:.*]] = insertelement <4 x float>

call void @llvm.memcpy.p0i8.p0i8.i32(i8* %out, i8* %a.cast2, i32 8, i32 0, i1 false)
; CHECK-NEXT: %[[outptr:.*]] = bitcast i8* %out to <2 x float>*
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