Commit 5350a489 authored by Huihui Zhang's avatar Huihui Zhang
Browse files

[ConstantFold][SVE] Fix constant fold for FoldReinterpretLoadFromConstPtr. 

Summary:
Bail out early for scalable vectors. As global variables are not expected
to be scalable.

Use explicit call of getFixedSize() to assert on places where scalable size
doesn't make sense.

Reviewers: sdesmalen, efriedma, apazos, huntergr, willlovett

Reviewed By: sdesmalen

Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74424
parent 5dcffdf5

llvm/lib/Analysis/ConstantFolding.cpp

+8 −3
Original line number Diff line number Diff line
@@ -501,6 +501,10 @@ bool ReadDataFromGlobal(Constant *C, uint64_t ByteOffset, unsigned char *CurPtr, 


Constant *FoldReinterpretLoadFromConstPtr(Constant *C, Type *LoadTy,

                                          const DataLayout &DL) {

  // Bail out early. Not expect to load from scalable global variable.

  if (LoadTy->isVectorTy() && LoadTy->getVectorIsScalable())

    return nullptr;



  auto *PTy = cast<PointerType>(C->getType());

  auto *IntType = dyn_cast<IntegerType>(LoadTy);
@@ -520,8 +524,8 @@ Constant *FoldReinterpretLoadFromConstPtr(Constant *C, Type *LoadTy, 
    else if (LoadTy->isDoubleTy())

      MapTy = Type::getInt64Ty(C->getContext());

    else if (LoadTy->isVectorTy()) {

      MapTy = PointerType::getIntNTy(C->getContext(),

                                     DL.getTypeSizeInBits(LoadTy));

      MapTy = PointerType::getIntNTy(

          C->getContext(), DL.getTypeSizeInBits(LoadTy).getFixedSize());

    } else

      return nullptr;
@@ -561,7 +565,8 @@ Constant *FoldReinterpretLoadFromConstPtr(Constant *C, Type *LoadTy, 
    return nullptr;



  int64_t Offset = OffsetAI.getSExtValue();

  int64_t InitializerSize = DL.getTypeAllocSize(GV->getInitializer()->getType());

  int64_t InitializerSize =

      DL.getTypeAllocSize(GV->getInitializer()->getType()).getFixedSize();



  // If we're not accessing anything in this constant, the result is undefined.

  if (Offset <= -1 * static_cast<int64_t>(BytesLoaded))

llvm/test/Analysis/ConstantFolding/vscale.ll

+14 −0
Original line number Diff line number Diff line
@@ -185,6 +185,20 @@ define <vscale x 4 x i32> @shufflevector() { 
  %i2 = shufflevector <vscale x 4 x i32> %i, <vscale x 4 x i32> undef, <vscale x 4 x i32> zeroinitializer

  ret <vscale x 4 x i32> %i2

}



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;; Memory Access and Addressing Operations

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define <vscale x 2 x double> @load() {

; CHECK-LABEL: @load(

; CHECK-NEXT:    [[R:%.*]] = load <vscale x 2 x double>, <vscale x 2 x double>* getelementptr (<vscale x 2 x double>, <vscale x 2 x double>* null, i64 1)

; CHECK-NEXT:    ret <vscale x 2 x double> [[R]]

;

  %r = load <vscale x 2 x double>, <vscale x 2 x double>* getelementptr (<vscale x 2 x double>, <vscale x 2 x double>* null, i64 1)

  ret <vscale x 2 x double> %r

}



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;; Conversion Operations

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