[llvm] [Scalarizer][DirectX] support structs return types (PR #111569)
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Tue Oct 8 10:43:30 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
@llvm/pr-subscribers-backend-directx
Author: Farzon Lotfi (farzonl)
<details>
<summary>Changes</summary>
Based on this RFC: https://discourse.llvm.org/t/rfc-allow-the-scalarizer-pass-to-scalarize-vectors-returned-in-structs/82306
LLVM intrinsics do not support out params. To get around this limitation implementers will make intrinsics return structs to capture a return type and an out param. This implementation detail should not impact scalarization since these cases should be elementwise operations.
## Three changes are needed.
- The CallInst visitor needs to be updated to handle Structs
- A new visitor is needed for `ExtractValue` instructions
- finsh needs to be update to handle structs so that insert elements are properly propogated.
## Testing changes
- Add support for `llvm.frexp`
- Add support for `llvm.dx.splitdouble`
---
Full diff: https://github.com/llvm/llvm-project/pull/111569.diff
5 Files Affected:
- (modified) llvm/include/llvm/IR/IntrinsicsDirectX.td (+2)
- (modified) llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp (+1)
- (modified) llvm/lib/Transforms/Scalar/Scalarizer.cpp (+97-2)
- (added) llvm/test/CodeGen/DirectX/split-double.ll (+40)
- (added) llvm/test/Transforms/Scalarizer/frexp.ll (+67)
``````````diff
diff --git a/llvm/include/llvm/IR/IntrinsicsDirectX.td b/llvm/include/llvm/IR/IntrinsicsDirectX.td
index f2b9e286ebb476..5f0f856df8e2b0 100644
--- a/llvm/include/llvm/IR/IntrinsicsDirectX.td
+++ b/llvm/include/llvm/IR/IntrinsicsDirectX.td
@@ -86,5 +86,7 @@ def int_dx_rsqrt : DefaultAttrsIntrinsic<[llvm_anyfloat_ty], [LLVMMatchType<0>]
def int_dx_wave_is_first_lane : DefaultAttrsIntrinsic<[llvm_i1_ty], [], [IntrConvergent]>;
def int_dx_sign : DefaultAttrsIntrinsic<[LLVMScalarOrSameVectorWidth<0, llvm_i32_ty>], [llvm_any_ty], [IntrNoMem]>;
def int_dx_step : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty, LLVMMatchType<0>], [IntrNoMem]>;
+def int_dx_splitdouble : DefaultAttrsIntrinsic<[llvm_anyint_ty, LLVMMatchType<0>],
+ [LLVMScalarOrSameVectorWidth<0, llvm_double_ty>], [IntrNoMem]>;
def int_dx_radians : DefaultAttrsIntrinsic<[llvm_anyfloat_ty], [LLVMMatchType<0>], [IntrNoMem]>;
}
diff --git a/llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp b/llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp
index be714b5c87895a..4ddf39a4337df6 100644
--- a/llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp
+++ b/llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp
@@ -28,6 +28,7 @@ bool DirectXTTIImpl::isTargetIntrinsicTriviallyScalarizable(
switch (ID) {
case Intrinsic::dx_frac:
case Intrinsic::dx_rsqrt:
+ case Intrinsic::dx_splitdouble:
return true;
default:
return false;
diff --git a/llvm/lib/Transforms/Scalar/Scalarizer.cpp b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
index 72728c0f839e5d..d8b052061c1ad5 100644
--- a/llvm/lib/Transforms/Scalar/Scalarizer.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalarizer.cpp
@@ -197,6 +197,23 @@ struct VectorLayout {
uint64_t SplitSize = 0;
};
+static bool isStructAllVectors(Type *Ty) {
+ if (!isa<StructType>(Ty))
+ return false;
+ if (Ty->getNumContainedTypes() < 1)
+ return false;
+ FixedVectorType *VecTy = dyn_cast<FixedVectorType>(Ty->getContainedType(0));
+ if (!VecTy)
+ return false;
+ unsigned VecSize = VecTy->getNumElements();
+ for (unsigned I = 1; I < Ty->getNumContainedTypes(); I++) {
+ VecTy = dyn_cast<FixedVectorType>(Ty->getContainedType(I));
+ if (!VecTy || VecSize != VecTy->getNumElements())
+ return false;
+ }
+ return true;
+}
+
/// Concatenate the given fragments to a single vector value of the type
/// described in @p VS.
static Value *concatenate(IRBuilder<> &Builder, ArrayRef<Value *> Fragments,
@@ -276,6 +293,7 @@ class ScalarizerVisitor : public InstVisitor<ScalarizerVisitor, bool> {
bool visitBitCastInst(BitCastInst &BCI);
bool visitInsertElementInst(InsertElementInst &IEI);
bool visitExtractElementInst(ExtractElementInst &EEI);
+ bool visitExtractValueInst(ExtractValueInst &EVI);
bool visitShuffleVectorInst(ShuffleVectorInst &SVI);
bool visitPHINode(PHINode &PHI);
bool visitLoadInst(LoadInst &LI);
@@ -667,6 +685,11 @@ bool ScalarizerVisitor::splitBinary(Instruction &I, const Splitter &Split) {
bool ScalarizerVisitor::isTriviallyScalarizable(Intrinsic::ID ID) {
if (isTriviallyVectorizable(ID))
return true;
+ // TODO: investigate vectorizable frexp
+ switch (ID) {
+ case Intrinsic::frexp:
+ return true;
+ }
return Intrinsic::isTargetIntrinsic(ID) &&
TTI->isTargetIntrinsicTriviallyScalarizable(ID);
}
@@ -674,7 +697,13 @@ bool ScalarizerVisitor::isTriviallyScalarizable(Intrinsic::ID ID) {
/// If a call to a vector typed intrinsic function, split into a scalar call per
/// element if possible for the intrinsic.
bool ScalarizerVisitor::splitCall(CallInst &CI) {
- std::optional<VectorSplit> VS = getVectorSplit(CI.getType());
+ Type *CallType = CI.getType();
+ bool AreAllVectors = isStructAllVectors(CallType);
+ std::optional<VectorSplit> VS;
+ if (AreAllVectors)
+ VS = getVectorSplit(CallType->getContainedType(0));
+ else
+ VS = getVectorSplit(CallType);
if (!VS)
return false;
@@ -699,6 +728,18 @@ bool ScalarizerVisitor::splitCall(CallInst &CI) {
if (isVectorIntrinsicWithOverloadTypeAtArg(ID, -1))
Tys.push_back(VS->SplitTy);
+ if (AreAllVectors) {
+ Type *PrevType = CallType->getContainedType(0);
+ Type *CallType = CI.getType();
+ for (unsigned I = 1; I < CallType->getNumContainedTypes(); I++) {
+ Type *CurrType = cast<FixedVectorType>(CallType->getContainedType(I));
+ if (PrevType != CurrType) {
+ std::optional<VectorSplit> CurrVS = getVectorSplit(CurrType);
+ Tys.push_back(CurrVS->SplitTy);
+ PrevType = CurrType;
+ }
+ }
+ }
// Assumes that any vector type has the same number of elements as the return
// vector type, which is true for all current intrinsics.
for (unsigned I = 0; I != NumArgs; ++I) {
@@ -1029,6 +1070,31 @@ bool ScalarizerVisitor::visitInsertElementInst(InsertElementInst &IEI) {
return true;
}
+bool ScalarizerVisitor::visitExtractValueInst(ExtractValueInst &EVI) {
+ Value *Op = EVI.getOperand(0);
+ Type *OpTy = Op->getType();
+ ValueVector Res;
+ if (!isStructAllVectors(OpTy))
+ return false;
+ Type *VecType = cast<FixedVectorType>(OpTy->getContainedType(0));
+ std::optional<VectorSplit> VS = getVectorSplit(VecType);
+ if (!VS)
+ return false;
+ IRBuilder<> Builder(&EVI);
+ Scatterer Op0 = scatter(&EVI, Op, *VS);
+ assert(!EVI.getIndices().empty() && "Make sure an index exists");
+ // Note for our use case we only care about the top level index.
+ unsigned Index = EVI.getIndices()[0];
+ for (unsigned OpIdx = 0; OpIdx < Op0.size(); ++OpIdx) {
+ Value *ResElem = Builder.CreateExtractValue(
+ Op0[OpIdx], Index, EVI.getName() + ".elem" + std::to_string(Index));
+ Res.push_back(ResElem);
+ }
+
+ gather(&EVI, Res, *VS);
+ return true;
+}
+
bool ScalarizerVisitor::visitExtractElementInst(ExtractElementInst &EEI) {
std::optional<VectorSplit> VS = getVectorSplit(EEI.getOperand(0)->getType());
if (!VS)
@@ -1195,7 +1261,7 @@ bool ScalarizerVisitor::finish() {
if (!Op->use_empty()) {
// The value is still needed, so recreate it using a series of
// insertelements and/or shufflevectors.
- Value *Res;
+ Value *Res = nullptr;
if (auto *Ty = dyn_cast<FixedVectorType>(Op->getType())) {
BasicBlock *BB = Op->getParent();
IRBuilder<> Builder(Op);
@@ -1208,6 +1274,35 @@ bool ScalarizerVisitor::finish() {
Res = concatenate(Builder, CV, VS, Op->getName());
Res->takeName(Op);
+ } else if (auto *Ty = dyn_cast<StructType>(Op->getType())) {
+ BasicBlock *BB = Op->getParent();
+ IRBuilder<> Builder(Op);
+ if (isa<PHINode>(Op))
+ Builder.SetInsertPoint(BB, BB->getFirstInsertionPt());
+
+ // Iterate over each element in the struct
+ unsigned NumOfStructElements = Ty->getNumElements();
+ SmallVector<ValueVector, 4> ElemCV(NumOfStructElements);
+ for (unsigned I = 0; I < NumOfStructElements; ++I) {
+ for (auto *CVelem : CV) {
+ Value *Elem = Builder.CreateExtractValue(
+ CVelem, I, Op->getName() + ".elem" + std::to_string(I));
+ ElemCV[I].push_back(Elem);
+ }
+ }
+ Res = PoisonValue::get(Ty);
+ for (unsigned I = 0; I < NumOfStructElements; ++I) {
+ Type *ElemTy = Ty->getElementType(I);
+ assert(isa<FixedVectorType>(ElemTy) &&
+ "Only Structs of all FixedVectorType supported");
+ VectorSplit VS = *getVectorSplit(ElemTy);
+ assert(VS.NumFragments == CV.size());
+
+ Value *ConcatenatedVector =
+ concatenate(Builder, ElemCV[I], VS, Op->getName());
+ Res = Builder.CreateInsertValue(Res, ConcatenatedVector, I,
+ Op->getName() + ".insert");
+ }
} else {
assert(CV.size() == 1 && Op->getType() == CV[0]->getType());
Res = CV[0];
diff --git a/llvm/test/CodeGen/DirectX/split-double.ll b/llvm/test/CodeGen/DirectX/split-double.ll
new file mode 100644
index 00000000000000..9b70e87ba4794e
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/split-double.ll
@@ -0,0 +1,40 @@
+; RUN: opt -passes='function(scalarizer<load-store>)' -S -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+; CHECK-LABEL: @test_vector_double_split_void
+define void @test_vector_double_split_void(<2 x double> noundef %d) {
+ ; CHECK: [[ee0:%.*]] = extractelement <2 x double> %d, i64 0
+ ; CHECK: [[ie0:%.*]] = call { i32, i32 } @llvm.dx.splitdouble.i32(double [[ee0]])
+ ; CHECK: [[ee1:%.*]] = extractelement <2 x double> %d, i64 1
+ ; CHECK: [[ie1:%.*]] = call { i32, i32 } @llvm.dx.splitdouble.i32(double [[ee1]])
+ ; CHECK-NOT: extractvalue { i32, i32 } {{.*}}, 0
+ ; CHECK-NOT: insertelement <2 x i32> {{.*}}, i32 {{.*}}, i64 0
+ %hlsl.asuint = call { <2 x i32>, <2 x i32> } @llvm.dx.splitdouble.v2i32(<2 x double> %d)
+ ret void
+}
+
+; CHECK-LABEL: @test_vector_double_split
+define noundef <3 x i32> @test_vector_double_split(<3 x double> noundef %d) {
+ ; CHECK: [[ee0:%.*]] = extractelement <3 x double> %d, i64 0
+ ; CHECK: [[ie0:%.*]] = call { i32, i32 } @llvm.dx.splitdouble.i32(double [[ee0]])
+ ; CHECK: [[ee1:%.*]] = extractelement <3 x double> %d, i64 1
+ ; CHECK: [[ie1:%.*]] = call { i32, i32 } @llvm.dx.splitdouble.i32(double [[ee1]])
+ ; CHECK: [[ee2:%.*]] = extractelement <3 x double> %d, i64 2
+ ; CHECK: [[ie2:%.*]] = call { i32, i32 } @llvm.dx.splitdouble.i32(double [[ee2]])
+ ; CHECK: [[ev00:%.*]] = extractvalue { i32, i32 } [[ie0]], 0
+ ; CHECK: [[ev01:%.*]] = extractvalue { i32, i32 } [[ie1]], 0
+ ; CHECK: [[ev02:%.*]] = extractvalue { i32, i32 } [[ie2]], 0
+ ; CHECK: [[ev10:%.*]] = extractvalue { i32, i32 } [[ie0]], 1
+ ; CHECK: [[ev11:%.*]] = extractvalue { i32, i32 } [[ie1]], 1
+ ; CHECK: [[ev12:%.*]] = extractvalue { i32, i32 } [[ie2]], 1
+ ; CHECK: [[add1:%.*]] = add i32 [[ev00]], [[ev10]]
+ ; CHECK: [[add2:%.*]] = add i32 [[ev01]], [[ev11]]
+ ; CHECK: [[add3:%.*]] = add i32 [[ev02]], [[ev12]]
+ ; CHECK: insertelement <3 x i32> poison, i32 [[add1]], i64 0
+ ; CHECK: insertelement <3 x i32> %{{.*}}, i32 [[add2]], i64 1
+ ; CHECK: insertelement <3 x i32> %{{.*}}, i32 [[add3]], i64 2
+ %hlsl.asuint = call { <3 x i32>, <3 x i32> } @llvm.dx.splitdouble.v3i32(<3 x double> %d)
+ %1 = extractvalue { <3 x i32>, <3 x i32> } %hlsl.asuint, 0
+ %2 = extractvalue { <3 x i32>, <3 x i32> } %hlsl.asuint, 1
+ %3 = add <3 x i32> %1, %2
+ ret <3 x i32> %3
+}
diff --git a/llvm/test/Transforms/Scalarizer/frexp.ll b/llvm/test/Transforms/Scalarizer/frexp.ll
new file mode 100644
index 00000000000000..48159b45c18960
--- /dev/null
+++ b/llvm/test/Transforms/Scalarizer/frexp.ll
@@ -0,0 +1,67 @@
+; RUN: opt %s -passes='function(scalarizer<load-store>)' -S | FileCheck %s
+
+; CHECK-LABEL: @test_vector_half_frexp_half
+define noundef <2 x half> @test_vector_half_frexp_half(<2 x half> noundef %h) {
+ ; CHECK: [[ee0:%.*]] = extractelement <2 x half> %h, i64 0
+ ; CHECK-NEXT: [[ie0:%.*]] = call { half, i32 } @llvm.frexp.f16.i32(half [[ee0]])
+ ; CHECK-NEXT: [[ee1:%.*]] = extractelement <2 x half> %h, i64 1
+ ; CHECK-NEXT: [[ie1:%.*]] = call { half, i32 } @llvm.frexp.f16.i32(half [[ee1]])
+ ; CHECK-NEXT: [[ev00:%.*]] = extractvalue { half, i32 } [[ie0]], 0
+ ; CHECK-NEXT: [[ev01:%.*]] = extractvalue { half, i32 } [[ie1]], 0
+ ; CHECK-NEXT: insertelement <2 x half> poison, half [[ev00]], i64 0
+ ; CHECK-NEXT: insertelement <2 x half> %{{.*}}, half [[ev01]], i64 1
+ %r = call { <2 x half>, <2 x i32> } @llvm.frexp.v2f32.v2i32(<2 x half> %h)
+ %e0 = extractvalue { <2 x half>, <2 x i32> } %r, 0
+ ret <2 x half> %e0
+}
+
+; CHECK-LABEL: @test_vector_half_frexp_int
+define noundef <2 x i32> @test_vector_half_frexp_int(<2 x half> noundef %h) {
+ ; CHECK: [[ee0:%.*]] = extractelement <2 x half> %h, i64 0
+ ; CHECK-NEXT: [[ie0:%.*]] = call { half, i32 } @llvm.frexp.f16.i32(half [[ee0]])
+ ; CHECK-NEXT: [[ee1:%.*]] = extractelement <2 x half> %h, i64 1
+ ; CHECK-NEXT: [[ie1:%.*]] = call { half, i32 } @llvm.frexp.f16.i32(half [[ee1]])
+ ; CHECK-NEXT: [[ev10:%.*]] = extractvalue { half, i32 } [[ie0]], 1
+ ; CHECK-NEXT: [[ev11:%.*]] = extractvalue { half, i32 } [[ie1]], 1
+ ; CHECK-NEXT: insertelement <2 x i32> poison, i32 [[ev10]], i64 0
+ ; CHECK-NEXT: insertelement <2 x i32> %{{.*}}, i32 [[ev11]], i64 1
+ %r = call { <2 x half>, <2 x i32> } @llvm.frexp.v2f32.v2i32(<2 x half> %h)
+ %e1 = extractvalue { <2 x half>, <2 x i32> } %r, 1
+ ret <2 x i32> %e1
+}
+
+; CHECK-LABEL: @test_vector_float_frexp_int
+define noundef <2 x float> @test_vector_float_frexp_int(<2 x float> noundef %f) {
+ ; CHECK: [[ee0:%.*]] = extractelement <2 x float> %f, i64 0
+ ; CHECK-NEXT: [[ie0:%.*]] = call { float, i32 } @llvm.frexp.f32.i32(float [[ee0]])
+ ; CHECK-NEXT: [[ee1:%.*]] = extractelement <2 x float> %f, i64 1
+ ; CHECK-NEXT: [[ie1:%.*]] = call { float, i32 } @llvm.frexp.f32.i32(float [[ee1]])
+ ; CHECK-NEXT: [[ev00:%.*]] = extractvalue { float, i32 } [[ie0]], 0
+ ; CHECK-NEXT: [[ev01:%.*]] = extractvalue { float, i32 } [[ie1]], 0
+ ; CHECK-NEXT: insertelement <2 x float> poison, float [[ev00]], i64 0
+ ; CHECK-NEXT: insertelement <2 x float> %{{.*}}, float [[ev01]], i64 1
+ ; CHECK-NEXT: extractvalue { float, i32 } [[ie0]], 1
+ ; CHECK-NEXT: extractvalue { float, i32 } [[ie1]], 1
+ %1 = call { <2 x float>, <2 x i32> } @llvm.frexp.v2f16.v2i32(<2 x float> %f)
+ %2 = extractvalue { <2 x float>, <2 x i32> } %1, 0
+ %3 = extractvalue { <2 x float>, <2 x i32> } %1, 1
+ ret <2 x float> %2
+}
+
+; CHECK-LABEL: @test_vector_double_frexp_int
+define noundef <2 x double> @test_vector_double_frexp_int(<2 x double> noundef %d) {
+ ; CHECK: [[ee0:%.*]] = extractelement <2 x double> %d, i64 0
+ ; CHECK-NEXT: [[ie0:%.*]] = call { double, i32 } @llvm.frexp.f64.i32(double [[ee0]])
+ ; CHECK-NEXT: [[ee1:%.*]] = extractelement <2 x double> %d, i64 1
+ ; CHECK-NEXT: [[ie1:%.*]] = call { double, i32 } @llvm.frexp.f64.i32(double [[ee1]])
+ ; CHECK-NEXT: [[ev00:%.*]] = extractvalue { double, i32 } [[ie0]], 0
+ ; CHECK-NEXT: [[ev01:%.*]] = extractvalue { double, i32 } [[ie1]], 0
+ ; CHECK-NEXT: insertelement <2 x double> poison, double [[ev00]], i64 0
+ ; CHECK-NEXT: insertelement <2 x double> %{{.*}}, double [[ev01]], i64 1
+ ; CHECK-NEXT: extractvalue { double, i32 } [[ie0]], 1
+ ; CHECK-NEXT: extractvalue { double, i32 } [[ie1]], 1
+ %1 = call { <2 x double>, <2 x i32> } @llvm.frexp.v2f64.v2i32(<2 x double> %d)
+ %2 = extractvalue { <2 x double>, <2 x i32> } %1, 0
+ %3 = extractvalue { <2 x double>, <2 x i32> } %1, 1
+ ret <2 x double> %2
+}
``````````
</details>
https://github.com/llvm/llvm-project/pull/111569
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