SROA: Generate selects instead of shuffles when blending values because this is the...

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

diff --git a/lib/Transforms/Scalar/SROA.cpp b/lib/Transforms/Scalar/SROA.cpp
index c383e2f8ed8596e3837d9bd7eabdca17263b3cdc..d073e789dcba34d3c8cdc35715095aa926641f7d 100644 (file)
--- a/lib/Transforms/Scalar/SROA.cpp
+++ b/lib/Transforms/Scalar/SROA.cpp
@@ -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;
 }
 

diff --git a/test/Transforms/SROA/vector-promotion.ll b/test/Transforms/SROA/vector-promotion.ll
index 02f6d040cc950cdde85e49e8566a200c4a951b9d..3336515770a37d4d997aa0576abb3ef0d26cf69a 100644 (file)
--- a/test/Transforms/SROA/vector-promotion.ll
+++ b/test/Transforms/SROA/vector-promotion.ll
@@ -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() {
@@ -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) {
@@ -326,7 +326,7 @@ 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*
@@ -334,7 +334,7 @@ entry:
 ; 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*
@@ -342,14 +342,14 @@ entry:
 ; 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>*