[llvm] 1d42ba2 - [BasicTTIImpl] Fix getCastInstrCost for scalable vectors by querying for ElementCount.

[Sander de Smalen via llvm-commits]

Author: Sander de Smalen
Date: 2021-02-12T08:28:52Z
New Revision: 1d42ba254fa3203f1ad5916ed414a84312f5bba9

URL: https://github.com/llvm/llvm-project/commit/1d42ba254fa3203f1ad5916ed414a84312f5bba9
DIFF: https://github.com/llvm/llvm-project/commit/1d42ba254fa3203f1ad5916ed414a84312f5bba9.diff

LOG: [BasicTTIImpl] Fix getCastInstrCost for scalable vectors by querying for ElementCount.

This fixes an overly restrictive assumption that the vector is a FixedVectorType,
in code that tries to calculate the cost of a cast operation when splitting
a too-wide vector. The algorithm works the same for scalable vectors, so this
patch removes the cast<FixedVectorType>.

Reviewed By: david-arm

Differential Revision: https://reviews.llvm.org/D96253

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/BasicTTIImpl.h
    llvm/test/Analysis/CostModel/AArch64/cast.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index 6596da1a4aae..206fdeab066f 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -852,9 +852,8 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
       bool SplitDst =
           TLI->getTypeAction(Dst->getContext(), TLI->getValueType(DL, Dst)) ==
           TargetLowering::TypeSplitVector;
-      if ((SplitSrc || SplitDst) &&
-          cast<FixedVectorType>(SrcVTy)->getNumElements() > 1 &&
-          cast<FixedVectorType>(DstVTy)->getNumElements() > 1) {
+      if ((SplitSrc || SplitDst) && SrcVTy->getElementCount().isVector() &&
+          DstVTy->getElementCount().isVector()) {
         Type *SplitDstTy = VectorType::getHalfElementsVectorType(DstVTy);
         Type *SplitSrcTy = VectorType::getHalfElementsVectorType(SrcVTy);
         T *TTI = static_cast<T *>(this);

diff  --git a/llvm/test/Analysis/CostModel/AArch64/cast.ll b/llvm/test/Analysis/CostModel/AArch64/cast.ll
index d55c2bca1fbb..f9b8ad1d9a07 100644
--- a/llvm/test/Analysis/CostModel/AArch64/cast.ll
+++ b/llvm/test/Analysis/CostModel/AArch64/cast.ll
@@ -696,7 +696,7 @@ define i32 @bitcasts() {
   ret i32 undef
 }
 
-define i32 @load_extends() {
+define i32 @load_extends() #0 {
 ; CHECK-LABEL: 'load_extends'
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadi8 = load i8, i8* undef
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadi16 = load i16, i16* undef
@@ -708,6 +708,8 @@ define i32 @load_extends() {
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadv4i16 = load <4 x i16>, <4 x i16>* undef
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadv2i32 = load <2 x i32>, <2 x i32>* undef
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadv4i32 = load <4 x i32>, <4 x i32>* undef
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadnxv2i32 = load <vscale x 2 x i32>, <vscale x 2 x i32>* undef
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %loadnxv4i32 = load <vscale x 4 x i32>, <vscale x 4 x i32>* undef
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %r0 = sext i8 %loadi8 to i16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %r1 = zext i8 %loadi8 to i16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %r2 = sext i8 %loadi8 to i32
@@ -734,6 +736,10 @@ define i32 @load_extends() {
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v11 = zext <2 x i32> %loadv2i32 to <2 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v12 = sext <4 x i32> %loadv4i32 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %v13 = zext <4 x i32> %loadv4i32 to <4 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %v14 = sext <vscale x 2 x i32> %loadnxv2i32 to <vscale x 2 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %v15 = zext <vscale x 2 x i32> %loadnxv2i32 to <vscale x 2 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v16 = sext <vscale x 4 x i32> %loadnxv4i32 to <vscale x 4 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %v17 = zext <vscale x 4 x i32> %loadnxv4i32 to <vscale x 4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
   %loadi8 = load i8, i8* undef
@@ -746,6 +752,8 @@ define i32 @load_extends() {
   %loadv4i16 = load <4 x i16>, <4 x i16>* undef
   %loadv2i32 = load <2 x i32>, <2 x i32>* undef
   %loadv4i32 = load <4 x i32>, <4 x i32>* undef
+  %loadnxv2i32 = load <vscale x 2 x i32>, <vscale x 2 x i32>* undef
+  %loadnxv4i32 = load <vscale x 4 x i32>, <vscale x 4 x i32>* undef
 
   %r0 = sext i8 %loadi8 to i16
   %r1 = zext i8 %loadi8 to i16
@@ -774,6 +782,10 @@ define i32 @load_extends() {
   %v11 = zext <2 x i32> %loadv2i32 to <2 x i64>
   %v12 = sext <4 x i32> %loadv4i32 to <4 x i64>
   %v13 = zext <4 x i32> %loadv4i32 to <4 x i64>
+  %v14 = sext <vscale x 2 x i32> %loadnxv2i32 to <vscale x 2 x i64>
+  %v15 = zext <vscale x 2 x i32> %loadnxv2i32 to <vscale x 2 x i64>
+  %v16 = sext <vscale x 4 x i32> %loadnxv4i32 to <vscale x 4 x i64>
+  %v17 = zext <vscale x 4 x i32> %loadnxv4i32 to <vscale x 4 x i64>
 
   ret i32 undef
 }
@@ -808,3 +820,5 @@ define i32 @store_truncs() {
   store i8 %r5, i8* undef
   ret i32 undef
 }
+
+attributes #0 = { "target-features"="+sve" }