[DirectX] Start the creation of a DXIL Instruction legalizer

llvm/lib/Target/DirectX/CMakeLists.txt

@@ -32,6 +32,7 @@ add_llvm_target(DirectXCodeGen
   DXILShaderFlags.cpp
   DXILTranslateMetadata.cpp
   DXILRootSignature.cpp
+  DXILLegalizePass.cpp
 
   LINK_COMPONENTS
   Analysis

llvm/lib/Target/DirectX/DXILLegalizePass.cpp

@@ -0,0 +1,212 @@
+//===- DXILLegalizePass.cpp - Legalizes llvm IR for DXIL ------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+//===---------------------------------------------------------------------===//
+///
+/// \file This file contains a pass to remove i8 truncations and i64 extract
+/// and insert elements.
+///
+//===----------------------------------------------------------------------===//
+#include "DXILLegalizePass.h"
+#include "DirectX.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include <functional>
+#include <map>
+#include <stack>
+#include <vector>
+
+#define DEBUG_TYPE "dxil-legalize"
+
+using namespace llvm;
+namespace {
+
+static bool fixI8TruncUseChain(Instruction &I,
+                               std::stack<Instruction *> &ToRemove,
+                               std::map<Value *, Value *> &ReplacedValues) {
+
+  auto *Cmp = dyn_cast<CmpInst>(&I);
+
+  if (auto *Trunc = dyn_cast<TruncInst>(&I)) {
+    if (Trunc->getDestTy()->isIntegerTy(8)) {
+      ReplacedValues[Trunc] = Trunc->getOperand(0);
+      ToRemove.push(Trunc);
+    }
+  } else if (I.getType()->isIntegerTy(8) ||
+             (Cmp && Cmp->getOperand(0)->getType()->isIntegerTy(8))) {
+    IRBuilder<> Builder(&I);
+
+    std::vector<Value *> NewOperands;
+    Type *InstrType = IntegerType::get(I.getContext(), 32);
+    for (unsigned OpIdx = 0; OpIdx < I.getNumOperands(); ++OpIdx) {
+      Value *Op = I.getOperand(OpIdx);
+      if (ReplacedValues.count(Op))
+        InstrType = ReplacedValues[Op]->getType();
+    }
+    for (unsigned OpIdx = 0; OpIdx < I.getNumOperands(); ++OpIdx) {
+      Value *Op = I.getOperand(OpIdx);
+      if (ReplacedValues.count(Op))
+        NewOperands.push_back(ReplacedValues[Op]);
+      else if (auto *Imm = dyn_cast<ConstantInt>(Op)) {
+        APInt Value = Imm->getValue();
+        unsigned NewBitWidth = InstrType->getIntegerBitWidth();
+        // Note: options here are sext or sextOrTrunc.
+        // Since i8 isn't supported, we assume new values
+        // will always have a higher bitness.
+        APInt NewValue = Value.sext(NewBitWidth);
+        NewOperands.push_back(ConstantInt::get(InstrType, NewValue));
+      } else {
+        assert(!Op->getType()->isIntegerTy(8));
+        NewOperands.push_back(Op);
+      }
+    }
+
+    Value *NewInst = nullptr;
+    if (auto *BO = dyn_cast<BinaryOperator>(&I)) {
+      NewInst =
+          Builder.CreateBinOp(BO->getOpcode(), NewOperands[0], NewOperands[1]);
+
+      if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(&I)) {
+        if (OBO->hasNoSignedWrap())
+          cast<BinaryOperator>(NewInst)->setHasNoSignedWrap();
+        if (OBO->hasNoUnsignedWrap())
+          cast<BinaryOperator>(NewInst)->setHasNoUnsignedWrap();
+      }
+    } else if (Cmp) {
+      NewInst = Builder.CreateCmp(Cmp->getPredicate(), NewOperands[0],
+                                  NewOperands[1]);
+      Cmp->replaceAllUsesWith(NewInst);
+    }
+
+    if (NewInst) {
+      ReplacedValues[&I] = NewInst;
+      ToRemove.push(&I);
+    }
+  } else if (auto *Cast = dyn_cast<CastInst>(&I)) {
+    if (Cast->getSrcTy()->isIntegerTy(8)) {
+      ToRemove.push(Cast);
+      Cast->replaceAllUsesWith(ReplacedValues[Cast->getOperand(0)]);
+    }
+  }
+
+  return !ToRemove.empty();
+}
+
+static bool
+downcastI64toI32InsertExtractElements(Instruction &I,
+                                      std::stack<Instruction *> &ToRemove,
+                                      std::map<Value *, Value *> &) {
+
+  if (auto *Extract = dyn_cast<ExtractElementInst>(&I)) {
+    Value *Idx = Extract->getIndexOperand();
+    auto *CI = dyn_cast<ConstantInt>(Idx);
+    if (CI && CI->getBitWidth() == 64) {
+      IRBuilder<> Builder(Extract);
+      int64_t IndexValue = CI->getSExtValue();
+      auto *Idx32 =
+          ConstantInt::get(Type::getInt32Ty(I.getContext()), IndexValue);
+      Value *NewExtract = Builder.CreateExtractElement(
+          Extract->getVectorOperand(), Idx32, Extract->getName());
+
+      Extract->replaceAllUsesWith(NewExtract);
+      ToRemove.push(Extract);
+    }
+  }
+
+  if (auto *Insert = dyn_cast<InsertElementInst>(&I)) {
+    Value *Idx = Insert->getOperand(2);
+    auto *CI = dyn_cast<ConstantInt>(Idx);
+    if (CI && CI->getBitWidth() == 64) {
+      int64_t IndexValue = CI->getSExtValue();
+      auto *Idx32 =
+          ConstantInt::get(Type::getInt32Ty(I.getContext()), IndexValue);
+      IRBuilder<> Builder(Insert);
+      Value *Insert32Index = Builder.CreateInsertElement(
+          Insert->getOperand(0), Insert->getOperand(1), Idx32,
+          Insert->getName());
+
+      Insert->replaceAllUsesWith(Insert32Index);
+      ToRemove.push(Insert);
+    }
+  }
+
+  return !ToRemove.empty();
+}
+
+class DXILLegalizationPipeline {
+
+public:
+  DXILLegalizationPipeline() { initializeLegalizationPipeline(); }
+
+  bool runLegalizationPipeline(Function &F) {
+    std::stack<Instruction *> ToRemove;
+    std::map<Value *, Value *> ReplacedValues;
+    bool MadeChanges = false;
+    for (auto &I : instructions(F)) {
+      for (auto &LegalizationFn : LegalizationPipeline) {
+        MadeChanges |= LegalizationFn(I, ToRemove, ReplacedValues);
+      }
+    }
+    while (!ToRemove.empty()) {
+      Instruction *I = ToRemove.top();
+      I->eraseFromParent();
+      ToRemove.pop();
+    }
+
+    return MadeChanges;
+  }
+
+private:
+  std::vector<std::function<bool(Instruction &, std::stack<Instruction *> &,
+                                 std::map<Value *, Value *> &)>>
+      LegalizationPipeline;
+
+  void initializeLegalizationPipeline() {
+    LegalizationPipeline.push_back(fixI8TruncUseChain);
+    LegalizationPipeline.push_back(downcastI64toI32InsertExtractElements);
+  }
+};
+
+class DXILLegalizeLegacy : public FunctionPass {
+
+public:
+  bool runOnFunction(Function &F) override;
+  DXILLegalizeLegacy() : FunctionPass(ID) {}
+
+  static char ID; // Pass identification.
+};
+} // namespace
+
+PreservedAnalyses DXILLegalizePass::run(Function &F,
+                                        FunctionAnalysisManager &FAM) {
+  DXILLegalizationPipeline DXLegalize;
+  bool MadeChanges = DXLegalize.runLegalizationPipeline(F);
+  if (!MadeChanges)
+    return PreservedAnalyses::all();
+  PreservedAnalyses PA;
+  return PA;
+}
+
+bool DXILLegalizeLegacy::runOnFunction(Function &F) {
+  DXILLegalizationPipeline DXLegalize;
+  return DXLegalize.runLegalizationPipeline(F);
+}
+
+char DXILLegalizeLegacy::ID = 0;
+
+INITIALIZE_PASS_BEGIN(DXILLegalizeLegacy, DEBUG_TYPE, "DXIL Legalizer", false,
+                      false)
+INITIALIZE_PASS_END(DXILLegalizeLegacy, DEBUG_TYPE, "DXIL Legalizer", false,
+                    false)
+
+FunctionPass *llvm::createDXILLegalizeLegacyPass() {
+  return new DXILLegalizeLegacy();
+}

llvm/lib/Target/DirectX/DXILLegalizePass.h

@@ -0,0 +1,22 @@
+//===- DXILLegalizePass.h - Legalizes llvm IR for DXIL --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===---------------------------------------------------------------------===//
+
+#ifndef LLVM_TARGET_DIRECTX_LEGALIZE_H
+#define LLVM_TARGET_DIRECTX_LEGALIZE_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class DXILLegalizePass : public PassInfoMixin<DXILLegalizePass> {
+public:
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
+};
+} // namespace llvm
+
+#endif // LLVM_TARGET_DIRECTX_LEGALIZE_H

llvm/lib/Target/DirectX/DirectX.h

@@ -47,6 +47,13 @@ void initializeDXILFlattenArraysLegacyPass(PassRegistry &);
 /// Pass to flatten arrays into a one dimensional DXIL legal form
 ModulePass *createDXILFlattenArraysLegacyPass();
 
+/// Initializer DXIL legalizationPass
+void initializeDXILLegalizeLegacyPass(PassRegistry &);
+
+/// Pass to Legalize DXIL by remove i8 truncations and i64 insert/extract
+/// elements
+FunctionPass *createDXILLegalizeLegacyPass();
+
 /// Initializer for DXILOpLowering
 void initializeDXILOpLoweringLegacyPass(PassRegistry &);
 

llvm/lib/Target/DirectX/DirectXPassRegistry.def

@@ -38,4 +38,5 @@ MODULE_PASS("print<dxil-root-signature>", dxil::RootSignatureAnalysisPrinter(dbg
 #define FUNCTION_PASS(NAME, CREATE_PASS)
 #endif
 FUNCTION_PASS("dxil-resource-access", DXILResourceAccess())
+FUNCTION_PASS("dxil-legalize", DXILLegalizePass())
 #undef FUNCTION_PASS

llvm/lib/Target/DirectX/DirectXTargetMachine.cpp

@@ -15,6 +15,7 @@
 #include "DXILDataScalarization.h"
 #include "DXILFlattenArrays.h"
 #include "DXILIntrinsicExpansion.h"
+#include "DXILLegalizePass.h"
 #include "DXILOpLowering.h"
 #include "DXILPrettyPrinter.h"
 #include "DXILResourceAccess.h"
@@ -52,6 +53,7 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTarget() {
   initializeDXILDataScalarizationLegacyPass(*PR);
   initializeDXILFlattenArraysLegacyPass(*PR);
   initializeScalarizerLegacyPassPass(*PR);
+  initializeDXILLegalizeLegacyPass(*PR);
   initializeDXILPrepareModulePass(*PR);
   initializeEmbedDXILPassPass(*PR);
   initializeWriteDXILPassPass(*PR);
@@ -99,6 +101,7 @@ class DirectXPassConfig : public TargetPassConfig {
     ScalarizerPassOptions DxilScalarOptions;
     DxilScalarOptions.ScalarizeLoadStore = true;
     addPass(createScalarizerPass(DxilScalarOptions));
+    addPass(createDXILLegalizeLegacyPass());
     addPass(createDXILTranslateMetadataLegacyPass());
     addPass(createDXILOpLoweringLegacyPass());
     addPass(createDXILPrepareModulePass());

llvm/test/CodeGen/DirectX/ResourceGlobalElimination.ll

@@ -19,8 +19,8 @@
 ; CHECK-LABEL define void @main()
 define void @main() local_unnamed_addr #0 {
 entry:
-  ; DXOP: %In_h.i1 = call %dx.types.Handle @dx.op.createHandle
-  ; DXOP: %Out_h.i2 = call %dx.types.Handle @dx.op.createHandle
+  ; DXOP: [[In_h_i:%.*]] = call %dx.types.Handle @dx.op.createHandle
+  ; DXOP: [[Out_h_i:%.*]] = call %dx.types.Handle @dx.op.createHandle
   %In_h.i = call target("dx.TypedBuffer", <4 x float>, 1, 0, 0) @llvm.dx.resource.handlefrombinding.tdx.TypedBuffer_v4f32_1_0_0t(i32 0, i32 0, i32 1, i32 0, i1 false)
   store target("dx.TypedBuffer", <4 x float>, 1, 0, 0) %In_h.i, ptr @In, align 4
   %Out_h.i = call target("dx.TypedBuffer", <4 x float>, 1, 0, 0) @llvm.dx.resource.handlefrombinding.tdx.TypedBuffer_v4f32_1_0_0t(i32 4, i32 1, i32 1, i32 0, i1 false)

llvm/test/CodeGen/DirectX/legalize-i64-extract-insert-elements.ll

@@ -0,0 +1,24 @@
+; RUN: opt -S -passes='dxil-legalize' -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+define noundef <4 x float> @float4_extract(<4 x float> noundef %a) {
+entry:
+  ; CHECK: [[ee0:%.*]] = extractelement <4 x float> %a, i32 0
+  ; CHECK: [[ee1:%.*]] = extractelement <4 x float> %a, i32 1
+  ; CHECK: [[ee2:%.*]] = extractelement <4 x float> %a, i32 2
+  ; CHECK: [[ee3:%.*]] = extractelement <4 x float> %a, i32 3
+  ; CHECK: insertelement <4 x float> poison, float [[ee0]], i32 0
+  ; CHECK: insertelement <4 x float> %{{.*}}, float [[ee1]], i32 1
+  ; CHECK: insertelement <4 x float> %{{.*}}, float [[ee2]], i32 2
+  ; CHECK: insertelement <4 x float> %{{.*}}, float [[ee3]], i32 3
+
+  %a.i0 = extractelement <4 x float> %a, i64 0
+  %a.i1 = extractelement <4 x float> %a, i64 1
+  %a.i2 = extractelement <4 x float> %a, i64 2
+  %a.i3 = extractelement <4 x float> %a, i64 3
+
+  %.upto0 = insertelement <4 x float> poison, float %a.i0, i64 0
+  %.upto1 = insertelement <4 x float> %.upto0, float %a.i1, i64 1
+  %.upto2 = insertelement <4 x float> %.upto1, float %a.i2, i64 2
+  %0 = insertelement <4 x float> %.upto2, float %a.i3, i64 3
+  ret <4 x float> %0
+}