Fix Operandreorder logic in SLPVectorizer to generate longer vectorizable chain.

This patch fixes 2 issues in reorderInputsAccordingToOpcode
1) AllSameOpcodeLeft and AllSameOpcodeRight was being calculated incorrectly resulting in code not being vectorized in few cases.
2) Adds logic to reorder operands if we get longer chain of consecutive loads enabling vectorization. Handled the same for cases were we have AltOpcode.
Thanks Michael for inputs and review.
Review: http://reviews.llvm.org/D6677

llvm-svn: 226547

1 files changed, 133 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SLPVectorizer/X86/addsub.ll b/llvm/test/Transforms/SLPVectorizer/X86/addsub.ll
index 174d4004684..d082b07b1d0 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/addsub.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/addsub.ll
@@ -10,6 +10,7 @@ target triple = "x86_64-unknown-linux-gnu"
 @fb = common global [4 x float] zeroinitializer, align 16
 @fc = common global [4 x float] zeroinitializer, align 16
 @fa = common global [4 x float] zeroinitializer, align 16
+@fd = common global [4 x float] zeroinitializer, align 16
 
 ; CHECK-LABEL: @addsub
 ; CHECK: %5 = add nsw <4 x i32> %3, %4
@@ -177,5 +178,137 @@ entry:
   ret void
 }
 
+; Check vectorization of following code for float data type-
+;  fc[0] = fb[0]+fa[0]; //swapped fb and fa
+;  fc[1] = fa[1]-fb[1];
+;  fc[2] = fa[2]+fb[2];
+;  fc[3] = fa[3]-fb[3];
+
+; CHECK-LABEL: @reorder_alt
+; CHECK: %3 = fadd <4 x float> %1, %2
+; CHECK: %4 = fsub <4 x float> %1, %2
+; CHECK: %5 = shufflevector <4 x float> %3, <4 x float> %4, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
+define void @reorder_alt() #0 {
+  %1 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 0), align 4
+  %2 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 0), align 4
+  %3 = fadd float %1, %2
+  store float %3, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 0), align 4
+  %4 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 1), align 4
+  %5 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 1), align 4
+  %6 = fsub float %4, %5
+  store float %6, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 1), align 4
+  %7 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 2), align 4
+  %8 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 2), align 4
+  %9 = fadd float %7, %8
+  store float %9, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 2), align 4
+  %10 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 3), align 4
+  %11 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 3), align 4
+  %12 = fsub float %10, %11
+  store float %12, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 3), align 4
+  ret void
+}
+
+; Check vectorization of following code for float data type-
+;  fc[0] = fa[0]+(fb[0]-fd[0]);
+;  fc[1] = fa[1]-(fb[1]+fd[1]);
+;  fc[2] = fa[2]+(fb[2]-fd[2]);
+;  fc[3] = fa[3]-(fd[3]+fb[3]); //swapped fd and fb 
+
+; CHECK-LABEL: @reorder_alt_subTree
+; CHECK: %4 = fsub <4 x float> %3, %2
+; CHECK: %5 = fadd <4 x float> %3, %2
+; CHECK: %6 = shufflevector <4 x float> %4, <4 x float> %5, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
+; CHECK: %7 = fadd <4 x float> %1, %6
+; CHECK: %8 = fsub <4 x float> %1, %6
+; CHECK: %9 = shufflevector <4 x float> %7, <4 x float> %8, <4 x i32> <i32 0, i32 5, i32 2, i32 7>
+define void @reorder_alt_subTree() #0 {
+  %1 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 0), align 4
+  %2 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 0), align 4
+  %3 = load float* getelementptr inbounds ([4 x float]* @fd, i32 0, i64 0), align 4
+  %4 = fsub float %2, %3
+  %5 = fadd float %1, %4
+  store float %5, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 0), align 4
+  %6 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 1), align 4
+  %7 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 1), align 4
+  %8 = load float* getelementptr inbounds ([4 x float]* @fd, i32 0, i64 1), align 4
+  %9 = fadd float %7, %8
+  %10 = fsub float %6, %9
+  store float %10, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 1), align 4
+  %11 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 2), align 4
+  %12 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 2), align 4
+  %13 = load float* getelementptr inbounds ([4 x float]* @fd, i32 0, i64 2), align 4
+  %14 = fsub float %12, %13
+  %15 = fadd float %11, %14
+  store float %15, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 2), align 4
+  %16 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 3), align 4
+  %17 = load float* getelementptr inbounds ([4 x float]* @fd, i32 0, i64 3), align 4
+  %18 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 3), align 4
+  %19 = fadd float %17, %18
+  %20 = fsub float %16, %19
+  store float %20, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 3), align 4
+  ret void
+}
+
+; Check vectorization of following code for double data type-
+;  c[0] = (a[0]+b[0])-d[0];
+;  c[1] = d[1]+(a[1]+b[1]); //swapped d[1] and (a[1]+b[1]) 
+
+; CHECK-LABEL: @reorder_alt_rightsubTree
+; CHECK: fadd <2 x double>
+; CHECK: fsub <2 x double>
+; CHECK: shufflevector <2 x double> 
+define void @reorder_alt_rightsubTree(double* nocapture %c, double* noalias nocapture readonly %a, double* noalias nocapture readonly %b, double* noalias nocapture readonly %d) {
+  %1 = load double* %a
+  %2 = load double* %b
+  %3 = fadd double %1, %2
+  %4 = load double* %d
+  %5 = fsub double %3, %4
+  store double %5, double* %c
+  %6 = getelementptr inbounds double* %d, i64 1
+  %7 = load double* %6
+  %8 = getelementptr inbounds double* %a, i64 1
+  %9 = load double* %8
+  %10 = getelementptr inbounds double* %b, i64 1
+  %11 = load double* %10
+  %12 = fadd double %9, %11
+  %13 = fadd double %7, %12
+  %14 = getelementptr inbounds double* %c, i64 1
+  store double %13, double* %14
+  ret void
+}
+
+; Dont vectorization of following code for float data type as sub is not commutative-
+;  fc[0] = fb[0]+fa[0];
+;  fc[1] = fa[1]-fb[1];
+;  fc[2] = fa[2]+fb[2];
+;  fc[3] = fb[3]-fa[3];
+;  In the above code we can swap the 1st and 2nd operation as fadd is commutative
+;  but not 2nd or 4th as fsub is not commutative. 
+
+; CHECK-LABEL: @no_vec_shuff_reorder
+; CHECK-NOT: fadd <4 x float>
+; CHECK-NOT: fsub <4 x float>
+; CHECK-NOT: shufflevector
+define void @no_vec_shuff_reorder() #0 {
+  %1 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 0), align 4
+  %2 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 0), align 4
+  %3 = fadd float %1, %2
+  store float %3, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 0), align 4
+  %4 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 1), align 4
+  %5 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 1), align 4
+  %6 = fsub float %4, %5
+  store float %6, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 1), align 4
+  %7 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 2), align 4
+  %8 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 2), align 4
+  %9 = fadd float %7, %8
+  store float %9, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 2), align 4
+  %10 = load float* getelementptr inbounds ([4 x float]* @fb, i32 0, i64 3), align 4
+  %11 = load float* getelementptr inbounds ([4 x float]* @fa, i32 0, i64 3), align 4
+  %12 = fsub float %10, %11
+  store float %12, float* getelementptr inbounds ([4 x float]* @fc, i32 0, i64 3), align 4
+  ret void
+}
+
+
 attributes #0 = { nounwind }