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[SPIRV] Handle ptrcast between array and vector types (llvm#166418)
This commit adds support for legalizing pointer casts between array and vector types within the SPIRV backend. This is necessary to handle cases where a vector is loaded from or stored to an array, which can occur with HLSL matrix types. The following changes are included: - Added to load a vector from an array. - Added to store a vector to an array. - Added the test case to verify the functionality.
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‎llvm/lib/Target/SPIRV/SPIRVLegalizePointerCast.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -116,6 +116,81 @@ class SPIRVLegalizePointerCast : public FunctionPass {
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return LI;
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}
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// Loads elements from an array and constructs a vector.
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Value *loadVectorFromArray(IRBuilder<> &B, FixedVectorType *TargetType,
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Value *Source) {
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// Load each element of the array.
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SmallVector<Value *, 4> LoadedElements;
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for (unsigned i = 0; i < TargetType->getNumElements(); ++i) {
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// Create a GEP to access the i-th element of the array.
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SmallVector<Type *, 2> Types = {Source->getType(), Source->getType()};
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SmallVector<Value *, 4> Args;
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Args.push_back(B.getInt1(false));
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Args.push_back(Source);
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Args.push_back(B.getInt32(0));
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Args.push_back(ConstantInt::get(B.getInt32Ty(), i));
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auto *ElementPtr = B.CreateIntrinsic(Intrinsic::spv_gep, {Types}, {Args});
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GR->buildAssignPtr(B, TargetType->getElementType(), ElementPtr);
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// Load the value from the element pointer.
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Value *Load = B.CreateLoad(TargetType->getElementType(), ElementPtr);
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buildAssignType(B, TargetType->getElementType(), Load);
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LoadedElements.push_back(Load);
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}
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// Build the vector from the loaded elements.
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Value *NewVector = PoisonValue::get(TargetType);
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buildAssignType(B, TargetType, NewVector);
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for (unsigned i = 0; i < TargetType->getNumElements(); ++i) {
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Value *Index = B.getInt32(i);
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SmallVector<Type *, 4> Types = {TargetType, TargetType,
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TargetType->getElementType(),
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Index->getType()};
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SmallVector<Value *> Args = {NewVector, LoadedElements[i], Index};
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NewVector = B.CreateIntrinsic(Intrinsic::spv_insertelt, {Types}, {Args});
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buildAssignType(B, TargetType, NewVector);
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}
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return NewVector;
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}
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// Stores elements from a vector into an array.
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void storeArrayFromVector(IRBuilder<> &B, Value *SrcVector,
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Value *DstArrayPtr, ArrayType *ArrTy,
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Align Alignment) {
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auto *VecTy = cast<FixedVectorType>(SrcVector->getType());
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// Ensure the element types of the array and vector are the same.
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assert(VecTy->getElementType() == ArrTy->getElementType() &&
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"Element types of array and vector must be the same.");
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for (unsigned i = 0; i < VecTy->getNumElements(); ++i) {
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// Create a GEP to access the i-th element of the array.
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SmallVector<Type *, 2> Types = {DstArrayPtr->getType(),
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DstArrayPtr->getType()};
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SmallVector<Value *, 4> Args;
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Args.push_back(B.getInt1(false));
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Args.push_back(DstArrayPtr);
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Args.push_back(B.getInt32(0));
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Args.push_back(ConstantInt::get(B.getInt32Ty(), i));
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auto *ElementPtr = B.CreateIntrinsic(Intrinsic::spv_gep, {Types}, {Args});
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GR->buildAssignPtr(B, ArrTy->getElementType(), ElementPtr);
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// Extract the element from the vector and store it.
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Value *Index = B.getInt32(i);
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SmallVector<Type *, 3> EltTypes = {VecTy->getElementType(), VecTy,
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Index->getType()};
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SmallVector<Value *, 2> EltArgs = {SrcVector, Index};
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Value *Element =
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B.CreateIntrinsic(Intrinsic::spv_extractelt, {EltTypes}, {EltArgs});
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buildAssignType(B, VecTy->getElementType(), Element);
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Types = {Element->getType(), ElementPtr->getType()};
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Args = {Element, ElementPtr, B.getInt16(2), B.getInt8(Alignment.value())};
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B.CreateIntrinsic(Intrinsic::spv_store, {Types}, {Args});
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}
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}
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// Replaces the load instruction to get rid of the ptrcast used as source
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// operand.
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void transformLoad(IRBuilder<> &B, LoadInst *LI, Value *CastedOperand,
@@ -154,6 +229,8 @@ class SPIRVLegalizePointerCast : public FunctionPass {
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// - float v = s.m;
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else if (SST && SST->getTypeAtIndex(0u) == ToTy)
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Output = loadFirstValueFromAggregate(B, ToTy, OriginalOperand, LI);
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else if (SAT && DVT && SAT->getElementType() == DVT->getElementType())
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Output = loadVectorFromArray(B, DVT, OriginalOperand);
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else
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llvm_unreachable("Unimplemented implicit down-cast from load.");
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@@ -288,6 +365,7 @@ class SPIRVLegalizePointerCast : public FunctionPass {
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auto *S_VT = dyn_cast<FixedVectorType>(FromTy);
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auto *D_ST = dyn_cast<StructType>(ToTy);
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auto *D_VT = dyn_cast<FixedVectorType>(ToTy);
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auto *D_AT = dyn_cast<ArrayType>(ToTy);
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B.SetInsertPoint(BadStore);
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if (D_ST && isTypeFirstElementAggregate(FromTy, D_ST))
@@ -296,6 +374,8 @@ class SPIRVLegalizePointerCast : public FunctionPass {
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storeVectorFromVector(B, Src, Dst, Alignment);
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else if (D_VT && !S_VT && FromTy == D_VT->getElementType())
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storeToFirstValueAggregate(B, Src, Dst, D_VT, Alignment);
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else if (D_AT && S_VT && S_VT->getElementType() == D_AT->getElementType())
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storeArrayFromVector(B, Src, Dst, D_AT, Alignment);
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else
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llvm_unreachable("Unsupported ptrcast use in store. Please fix.");
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‎llvm/test/CodeGen/SPIRV/pointers/load-store-vec-from-array.ll‎

Lines changed: 54 additions & 0 deletions
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@@ -0,0 +1,54 @@
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; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv-unknown-vulkan %s -o - | FileCheck %s
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; RUN: %if spirv-tools %{ llc -O0 -verify-machineinstrs -mtriple=spirv-unknown-vulkan %s -o - -filetype=obj | spirv-val %}
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; CHECK-DAG: [[FLOAT:%[0-9]+]] = OpTypeFloat 32
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; CHECK-DAG: [[VEC4FLOAT:%[0-9]+]] = OpTypeVector [[FLOAT]] 4
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; CHECK-DAG: [[UINT_TYPE:%[0-9]+]] = OpTypeInt 32 0
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; CHECK-DAG: [[UINT4:%[0-9]+]] = OpConstant [[UINT_TYPE]] 4
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; CHECK-DAG: [[ARRAY4FLOAT:%[0-9]+]] = OpTypeArray [[FLOAT]] [[UINT4]]
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; CHECK-DAG: [[PTR_ARRAY4FLOAT:%[0-9]+]] = OpTypePointer Private [[ARRAY4FLOAT]]
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; CHECK-DAG: [[G_IN:%[0-9]+]] = OpVariable [[PTR_ARRAY4FLOAT]] Private
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; CHECK-DAG: [[G_OUT:%[0-9]+]] = OpVariable [[PTR_ARRAY4FLOAT]] Private
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; CHECK-DAG: [[UINT0:%[0-9]+]] = OpConstant [[UINT_TYPE]] 0
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; CHECK-DAG: [[UINT1:%[0-9]+]] = OpConstant [[UINT_TYPE]] 1
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; CHECK-DAG: [[UINT2:%[0-9]+]] = OpConstant [[UINT_TYPE]] 2
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; CHECK-DAG: [[UINT3:%[0-9]+]] = OpConstant [[UINT_TYPE]] 3
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; CHECK-DAG: [[PTR_FLOAT:%[0-9]+]] = OpTypePointer Private [[FLOAT]]
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; CHECK-DAG: [[UNDEF_VEC:%[0-9]+]] = OpUndef [[VEC4FLOAT]]
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@G_in = internal addrspace(10) global [4 x float] zeroinitializer
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@G_out = internal addrspace(10) global [4 x float] zeroinitializer
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define spir_func void @main() {
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entry:
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; CHECK: [[GEP0:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_IN]] [[UINT0]]
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; CHECK-NEXT: [[LOAD0:%[0-9]+]] = OpLoad [[FLOAT]] [[GEP0]]
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; CHECK-NEXT: [[GEP1:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_IN]] [[UINT1]]
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; CHECK-NEXT: [[LOAD1:%[0-9]+]] = OpLoad [[FLOAT]] [[GEP1]]
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; CHECK-NEXT: [[GEP2:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_IN]] [[UINT2]]
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; CHECK-NEXT: [[LOAD2:%[0-9]+]] = OpLoad [[FLOAT]] [[GEP2]]
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; CHECK-NEXT: [[GEP3:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_IN]] [[UINT3]]
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; CHECK-NEXT: [[LOAD3:%[0-9]+]] = OpLoad [[FLOAT]] [[GEP3]]
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; CHECK-NEXT: [[VEC_INSERT0:%[0-9]+]] = OpCompositeInsert [[VEC4FLOAT]] [[LOAD0]] [[UNDEF_VEC]] 0
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; CHECK-NEXT: [[VEC_INSERT1:%[0-9]+]] = OpCompositeInsert [[VEC4FLOAT]] [[LOAD1]] [[VEC_INSERT0]] 1
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; CHECK-NEXT: [[VEC_INSERT2:%[0-9]+]] = OpCompositeInsert [[VEC4FLOAT]] [[LOAD2]] [[VEC_INSERT1]] 2
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; CHECK-NEXT: [[VEC:%[0-9]+]] = OpCompositeInsert [[VEC4FLOAT]] [[LOAD3]] [[VEC_INSERT2]] 3
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%0 = load <4 x float>, ptr addrspace(10) @G_in, align 64
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; CHECK-NEXT: [[GEP_OUT0:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_OUT]] [[UINT0]]
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; CHECK-NEXT: [[VEC_EXTRACT0:%[0-9]+]] = OpCompositeExtract [[FLOAT]] [[VEC]] 0
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; CHECK-NEXT: OpStore [[GEP_OUT0]] [[VEC_EXTRACT0]]
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; CHECK-NEXT: [[GEP_OUT1:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_OUT]] [[UINT1]]
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; CHECK-NEXT: [[VEC_EXTRACT1:%[0-9]+]] = OpCompositeExtract [[FLOAT]] [[VEC]] 1
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; CHECK-NEXT: OpStore [[GEP_OUT1]] [[VEC_EXTRACT1]]
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; CHECK-NEXT: [[GEP_OUT2:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_OUT]] [[UINT2]]
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; CHECK-NEXT: [[VEC_EXTRACT2:%[0-9]+]] = OpCompositeExtract [[FLOAT]] [[VEC]] 2
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; CHECK-NEXT: OpStore [[GEP_OUT2]] [[VEC_EXTRACT2]]
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; CHECK-NEXT: [[GEP_OUT3:%[0-9]+]] = OpAccessChain [[PTR_FLOAT]] [[G_OUT]] [[UINT3]]
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; CHECK-NEXT: [[VEC_EXTRACT3:%[0-9]+]] = OpCompositeExtract [[FLOAT]] [[VEC]] 3
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; CHECK-NEXT: OpStore [[GEP_OUT3]] [[VEC_EXTRACT3]]
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store <4 x float> %0, ptr addrspace(10) @G_out, align 64
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; CHECK-NEXT: OpReturn
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ret void
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}

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