1 files changed, 175 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/ExpandReductions.cpp b/llvm/lib/CodeGen/ExpandReductions.cpp
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index 000000000000..1069a2423b8b
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+++ b/llvm/lib/CodeGen/ExpandReductions.cpp
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+//===--- ExpandReductions.cpp - Expand experimental reduction intrinsics --===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass implements IR expansion for reduction intrinsics, allowing targets
+// to enable the experimental intrinsics until just before codegen.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/ExpandReductions.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils/LoopUtils.h"
+
+using namespace llvm;
+
+namespace {
+
+unsigned getOpcode(Intrinsic::ID ID) {
+  switch (ID) {
+  case Intrinsic::experimental_vector_reduce_v2_fadd:
+    return Instruction::FAdd;
+  case Intrinsic::experimental_vector_reduce_v2_fmul:
+    return Instruction::FMul;
+  case Intrinsic::experimental_vector_reduce_add:
+    return Instruction::Add;
+  case Intrinsic::experimental_vector_reduce_mul:
+    return Instruction::Mul;
+  case Intrinsic::experimental_vector_reduce_and:
+    return Instruction::And;
+  case Intrinsic::experimental_vector_reduce_or:
+    return Instruction::Or;
+  case Intrinsic::experimental_vector_reduce_xor:
+    return Instruction::Xor;
+  case Intrinsic::experimental_vector_reduce_smax:
+  case Intrinsic::experimental_vector_reduce_smin:
+  case Intrinsic::experimental_vector_reduce_umax:
+  case Intrinsic::experimental_vector_reduce_umin:
+    return Instruction::ICmp;
+  case Intrinsic::experimental_vector_reduce_fmax:
+  case Intrinsic::experimental_vector_reduce_fmin:
+    return Instruction::FCmp;
+  default:
+    llvm_unreachable("Unexpected ID");
+  }
+}
+
+RecurrenceDescriptor::MinMaxRecurrenceKind getMRK(Intrinsic::ID ID) {
+  switch (ID) {
+  case Intrinsic::experimental_vector_reduce_smax:
+    return RecurrenceDescriptor::MRK_SIntMax;
+  case Intrinsic::experimental_vector_reduce_smin:
+    return RecurrenceDescriptor::MRK_SIntMin;
+  case Intrinsic::experimental_vector_reduce_umax:
+    return RecurrenceDescriptor::MRK_UIntMax;
+  case Intrinsic::experimental_vector_reduce_umin:
+    return RecurrenceDescriptor::MRK_UIntMin;
+  case Intrinsic::experimental_vector_reduce_fmax:
+    return RecurrenceDescriptor::MRK_FloatMax;
+  case Intrinsic::experimental_vector_reduce_fmin:
+    return RecurrenceDescriptor::MRK_FloatMin;
+  default:
+    return RecurrenceDescriptor::MRK_Invalid;
+  }
+}
+
+bool expandReductions(Function &F, const TargetTransformInfo *TTI) {
+  bool Changed = false;
+  SmallVector<IntrinsicInst *, 4> Worklist;
+  for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
+    if (auto II = dyn_cast<IntrinsicInst>(&*I))
+      Worklist.push_back(II);
+
+  for (auto *II : Worklist) {
+    if (!TTI->shouldExpandReduction(II))
+      continue;
+
+    FastMathFlags FMF =
+        isa<FPMathOperator>(II) ? II->getFastMathFlags() : FastMathFlags{};
+    Intrinsic::ID ID = II->getIntrinsicID();
+    RecurrenceDescriptor::MinMaxRecurrenceKind MRK = getMRK(ID);
+
+    Value *Rdx = nullptr;
+    IRBuilder<> Builder(II);
+    IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
+    Builder.setFastMathFlags(FMF);
+    switch (ID) {
+    case Intrinsic::experimental_vector_reduce_v2_fadd:
+    case Intrinsic::experimental_vector_reduce_v2_fmul: {
+      // FMFs must be attached to the call, otherwise it's an ordered reduction
+      // and it can't be handled by generating a shuffle sequence.
+      Value *Acc = II->getArgOperand(0);
+      Value *Vec = II->getArgOperand(1);
+      if (!FMF.allowReassoc())
+        Rdx = getOrderedReduction(Builder, Acc, Vec, getOpcode(ID), MRK);
+      else {
+        Rdx = getShuffleReduction(Builder, Vec, getOpcode(ID), MRK);
+        Rdx = Builder.CreateBinOp((Instruction::BinaryOps)getOpcode(ID),
+                                  Acc, Rdx, "bin.rdx");
+      }
+    } break;
+    case Intrinsic::experimental_vector_reduce_add:
+    case Intrinsic::experimental_vector_reduce_mul:
+    case Intrinsic::experimental_vector_reduce_and:
+    case Intrinsic::experimental_vector_reduce_or:
+    case Intrinsic::experimental_vector_reduce_xor:
+    case Intrinsic::experimental_vector_reduce_smax:
+    case Intrinsic::experimental_vector_reduce_smin:
+    case Intrinsic::experimental_vector_reduce_umax:
+    case Intrinsic::experimental_vector_reduce_umin:
+    case Intrinsic::experimental_vector_reduce_fmax:
+    case Intrinsic::experimental_vector_reduce_fmin: {
+      Value *Vec = II->getArgOperand(0);
+      Rdx = getShuffleReduction(Builder, Vec, getOpcode(ID), MRK);
+    } break;
+    default:
+      continue;
+    }
+    II->replaceAllUsesWith(Rdx);
+    II->eraseFromParent();
+    Changed = true;
+  }
+  return Changed;
+}
+
+class ExpandReductions : public FunctionPass {
+public:
+  static char ID;
+  ExpandReductions() : FunctionPass(ID) {
+    initializeExpandReductionsPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override {
+    const auto *TTI =&getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
+    return expandReductions(F, TTI);
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<TargetTransformInfoWrapperPass>();
+    AU.setPreservesCFG();
+  }
+};
+}
+
+char ExpandReductions::ID;
+INITIALIZE_PASS_BEGIN(ExpandReductions, "expand-reductions",
+                      "Expand reduction intrinsics", false, false)
+INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
+INITIALIZE_PASS_END(ExpandReductions, "expand-reductions",
+                    "Expand reduction intrinsics", false, false)
+
+FunctionPass *llvm::createExpandReductionsPass() {
+  return new ExpandReductions();
+}
+
+PreservedAnalyses ExpandReductionsPass::run(Function &F,
+                                            FunctionAnalysisManager &AM) {
+  const auto &TTI = AM.getResult<TargetIRAnalysis>(F);
+  if (!expandReductions(F, &TTI))
+    return PreservedAnalyses::all();
+  PreservedAnalyses PA;
+  PA.preserveSet<CFGAnalyses>();
+  return PA;
+}