llvm-project/llvm/lib/CodeGen/ExpandReductions.cpp

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//===--- ExpandReductions.cpp - Expand experimental reduction intrinsics --===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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_fadd:
return Instruction::FAdd;
case Intrinsic::experimental_vector_reduce_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) {
IRBuilder<> Builder(II);
Value *Vec = nullptr;
auto ID = II->getIntrinsicID();
auto MRK = RecurrenceDescriptor::MRK_Invalid;
switch (ID) {
case Intrinsic::experimental_vector_reduce_fadd:
case Intrinsic::experimental_vector_reduce_fmul:
// FMFs must be attached to the call, otherwise it's an ordered reduction
// and it can't be handled by generating this shuffle sequence.
// TODO: Implement scalarization of ordered reductions here for targets
// without native support.
if (!II->getFastMathFlags().unsafeAlgebra())
continue;
Vec = II->getArgOperand(1);
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:
Vec = II->getArgOperand(0);
MRK = getMRK(ID);
break;
default:
continue;
}
if (!TTI->shouldExpandReduction(II))
continue;
auto Rdx = getShuffleReduction(Builder, Vec, getOpcode(ID), MRK);
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;
}