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[LowerBufferFatPointers] Fix support for GEP T, p7, <N x T> idxs #126126

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Merged
merged 3 commits into from
Feb 12, 2025
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[LowerBufferFatPointers] Fix support for GEP T, p7, <N x T> idxs #126126

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[LowerBufferFatPointers] Fix support for GEP T, p7, <N x T> idxs
krzysz00 Feb 6, 2025
28a28d8
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krzysz00 Feb 10, 2025
33fbcc5
Update llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
krzysz00 Feb 11, 2025
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18 changes: 15 additions & 3 deletions llvm/lib/Target/AMDGPU/AMDGPULowerBufferFatPointers.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1804,14 +1804,26 @@ PtrParts SplitPtrStructs::visitGetElementPtrInst(GetElementPtrInst &GEP) {
bool IsNUW = GEP.hasNoUnsignedWrap();
bool IsNUSW = GEP.hasNoUnsignedSignedWrap();

Type *ResTy = GEP.getType();
std::optional<ElementCount> ResEC;
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I don't see the point of ResEC, can just use the dyn_cast<VectorType> result later?

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Should be fixed

if (auto *ResVT = dyn_cast<VectorType>(ResTy->getStructElementType(0)))
ResEC = ResVT->getElementCount();
bool HasPtrVecIn = isa<VectorType>(Off->getType());
bool BroadcastsPtr = ResEC.has_value() && !HasPtrVecIn;

// In order to call emitGEPOffset() and thus not have to reimplement it,
// we need the GEP result to have ptr addrspace(7) type.
Type *FatPtrTy = IRB.getPtrTy(AMDGPUAS::BUFFER_FAT_POINTER);
if (auto *VT = dyn_cast<VectorType>(Off->getType()))
FatPtrTy = VectorType::get(FatPtrTy, VT->getElementCount());
if (ResEC.has_value())
FatPtrTy = VectorType::get(FatPtrTy, *ResEC);
GEP.mutateType(FatPtrTy);
Value *OffAccum = emitGEPOffset(&IRB, DL, &GEP);
GEP.mutateType(Ptr->getType());
GEP.mutateType(ResTy);

if (BroadcastsPtr) {
Rsrc = IRB.CreateVectorSplat(*ResEC, Rsrc, Rsrc->getName());
Off = IRB.CreateVectorSplat(*ResEC, Off, Off->getName());
}
if (match(OffAccum, m_Zero())) { // Constant-zero offset
SplitUsers.insert(&GEP);
return {Rsrc, Off};
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18 changes: 18 additions & 0 deletions llvm/test/CodeGen/AMDGPU/lower-buffer-fat-pointers-pointer-ops.ll
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Expand Up @@ -59,6 +59,24 @@ define <2 x ptr addrspace(7)> @gep_vector_scalar(<2 x ptr addrspace(7)> %in, i64
ret <2 x ptr addrspace(7)> %ret
}

define <2 x ptr addrspace(7)> @gep_scalar_vector(ptr addrspace(7) %in, <2 x i32> %idxs) {
; CHECK-LABEL: define { <2 x ptr addrspace(8)>, <2 x i32> } @gep_scalar_vector
; CHECK-SAME: ({ ptr addrspace(8), i32 } [[IN:%.*]], <2 x i32> [[IDXS:%.*]]) #[[ATTR0]] {
; CHECK-NEXT: [[IN_RSRC:%.*]] = extractvalue { ptr addrspace(8), i32 } [[IN]], 0
; CHECK-NEXT: [[IN_OFF:%.*]] = extractvalue { ptr addrspace(8), i32 } [[IN]], 1
; CHECK-NEXT: [[IN_RSRC_SPLATINSERT:%.*]] = insertelement <2 x ptr addrspace(8)> poison, ptr addrspace(8) [[IN_RSRC]], i64 0
; CHECK-NEXT: [[IN_RSRC_SPLAT:%.*]] = shufflevector <2 x ptr addrspace(8)> [[IN_RSRC_SPLATINSERT]], <2 x ptr addrspace(8)> poison, <2 x i32> zeroinitializer
; CHECK-NEXT: [[IN_OFF_SPLATINSERT:%.*]] = insertelement <2 x i32> poison, i32 [[IN_OFF]], i64 0
; CHECK-NEXT: [[IN_OFF_SPLAT:%.*]] = shufflevector <2 x i32> [[IN_OFF_SPLATINSERT]], <2 x i32> poison, <2 x i32> zeroinitializer
; CHECK-NEXT: [[RET:%.*]] = add <2 x i32> [[IN_OFF_SPLAT]], [[IDXS]]
; CHECK-NEXT: [[TMP1:%.*]] = insertvalue { <2 x ptr addrspace(8)>, <2 x i32> } poison, <2 x ptr addrspace(8)> [[IN_RSRC_SPLAT]], 0
; CHECK-NEXT: [[TMP2:%.*]] = insertvalue { <2 x ptr addrspace(8)>, <2 x i32> } [[TMP1]], <2 x i32> [[RET]], 1
; CHECK-NEXT: ret { <2 x ptr addrspace(8)>, <2 x i32> } [[TMP2]]
;
%ret = getelementptr inbounds i8, ptr addrspace(7) %in, <2 x i32> %idxs
ret <2 x ptr addrspace(7)> %ret
}

define ptr addrspace(7) @simple_gep(ptr addrspace(7) %ptr, i32 %off) {
; CHECK-LABEL: define { ptr addrspace(8), i32 } @simple_gep
; CHECK-SAME: ({ ptr addrspace(8), i32 } [[PTR:%.*]], i32 [[OFF:%.*]]) #[[ATTR0]] {
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