1329 lines
53 KiB
C++
1329 lines
53 KiB
C++
//===- IROutliner.cpp -- Outline Similar Regions ----------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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// Implementation for the IROutliner which is used by the IROutliner Pass.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/IPO/IROutliner.h"
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#include "llvm/Analysis/IRSimilarityIdentifier.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/IR/Attributes.h"
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#include "llvm/IR/PassManager.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Transforms/IPO.h"
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#include <map>
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#include <set>
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#include <vector>
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#define DEBUG_TYPE "iroutliner"
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using namespace llvm;
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using namespace IRSimilarity;
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/// The OutlinableGroup holds all the overarching information for outlining
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/// a set of regions that are structurally similar to one another, such as the
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/// types of the overall function, the output blocks, the sets of stores needed
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/// and a list of the different regions. This information is used in the
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/// deduplication of extracted regions with the same structure.
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struct OutlinableGroup {
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/// The sections that could be outlined
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std::vector<OutlinableRegion *> Regions;
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/// The argument types for the function created as the overall function to
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/// replace the extracted function for each region.
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std::vector<Type *> ArgumentTypes;
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/// The FunctionType for the overall function.
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FunctionType *OutlinedFunctionType = nullptr;
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/// The Function for the collective overall function.
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Function *OutlinedFunction = nullptr;
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/// Flag for whether we should not consider this group of OutlinableRegions
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/// for extraction.
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bool IgnoreGroup = false;
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/// The return block for the overall function.
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BasicBlock *EndBB = nullptr;
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/// Flag for whether the \ref ArgumentTypes have been defined after the
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/// extraction of the first region.
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bool InputTypesSet = false;
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/// The number of input values in \ref ArgumentTypes. Anything after this
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/// index in ArgumentTypes is an output argument.
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unsigned NumAggregateInputs = 0;
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/// For the \ref Regions, we look at every Value. If it is a constant,
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/// we check whether it is the same in Region.
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///
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/// \param [in,out] NotSame contains the global value numbers where the
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/// constant is not always the same, and must be passed in as an argument.
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void findSameConstants(DenseSet<unsigned> &NotSame);
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};
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/// Move the contents of \p SourceBB to before the last instruction of \p
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/// TargetBB.
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/// \param SourceBB - the BasicBlock to pull Instructions from.
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/// \param TargetBB - the BasicBlock to put Instruction into.
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static void moveBBContents(BasicBlock &SourceBB, BasicBlock &TargetBB) {
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BasicBlock::iterator BBCurr, BBEnd, BBNext;
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for (BBCurr = SourceBB.begin(), BBEnd = SourceBB.end(); BBCurr != BBEnd;
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BBCurr = BBNext) {
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BBNext = std::next(BBCurr);
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BBCurr->moveBefore(TargetBB, TargetBB.end());
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}
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}
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void OutlinableRegion::splitCandidate() {
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assert(!CandidateSplit && "Candidate already split!");
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Instruction *StartInst = (*Candidate->begin()).Inst;
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Instruction *EndInst = (*Candidate->end()).Inst;
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assert(StartInst && EndInst && "Expected a start and end instruction?");
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StartBB = StartInst->getParent();
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PrevBB = StartBB;
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// The basic block gets split like so:
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// block: block:
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// inst1 inst1
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// inst2 inst2
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// region1 br block_to_outline
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// region2 block_to_outline:
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// region3 -> region1
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// region4 region2
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// inst3 region3
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// inst4 region4
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// br block_after_outline
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// block_after_outline:
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// inst3
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// inst4
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std::string OriginalName = PrevBB->getName().str();
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StartBB = PrevBB->splitBasicBlock(StartInst, OriginalName + "_to_outline");
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// This is the case for the inner block since we do not have to include
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// multiple blocks.
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EndBB = StartBB;
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FollowBB = EndBB->splitBasicBlock(EndInst, OriginalName + "_after_outline");
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CandidateSplit = true;
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}
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void OutlinableRegion::reattachCandidate() {
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assert(CandidateSplit && "Candidate is not split!");
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// The basic block gets reattached like so:
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// block: block:
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// inst1 inst1
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// inst2 inst2
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// br block_to_outline region1
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// block_to_outline: -> region2
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// region1 region3
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// region2 region4
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// region3 inst3
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// region4 inst4
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// br block_after_outline
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// block_after_outline:
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// inst3
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// inst4
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assert(StartBB != nullptr && "StartBB for Candidate is not defined!");
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assert(FollowBB != nullptr && "StartBB for Candidate is not defined!");
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// StartBB should only have one predecessor since we put an unconditional
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// branch at the end of PrevBB when we split the BasicBlock.
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PrevBB = StartBB->getSinglePredecessor();
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assert(PrevBB != nullptr &&
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"No Predecessor for the region start basic block!");
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assert(PrevBB->getTerminator() && "Terminator removed from PrevBB!");
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assert(EndBB->getTerminator() && "Terminator removed from EndBB!");
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PrevBB->getTerminator()->eraseFromParent();
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EndBB->getTerminator()->eraseFromParent();
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moveBBContents(*StartBB, *PrevBB);
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BasicBlock *PlacementBB = PrevBB;
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if (StartBB != EndBB)
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PlacementBB = EndBB;
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moveBBContents(*FollowBB, *PlacementBB);
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PrevBB->replaceSuccessorsPhiUsesWith(StartBB, PrevBB);
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PrevBB->replaceSuccessorsPhiUsesWith(FollowBB, PlacementBB);
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StartBB->eraseFromParent();
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FollowBB->eraseFromParent();
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// Make sure to save changes back to the StartBB.
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StartBB = PrevBB;
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EndBB = nullptr;
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PrevBB = nullptr;
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FollowBB = nullptr;
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CandidateSplit = false;
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}
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/// Find whether \p V matches the Constants previously found for the \p GVN.
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///
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/// \param V - The value to check for consistency.
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/// \param GVN - The global value number assigned to \p V.
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/// \param GVNToConstant - The mapping of global value number to Constants.
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/// \returns true if the Value matches the Constant mapped to by V and false if
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/// it \p V is a Constant but does not match.
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/// \returns None if \p V is not a Constant.
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static Optional<bool>
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constantMatches(Value *V, unsigned GVN,
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DenseMap<unsigned, Constant *> &GVNToConstant) {
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// See if we have a constants
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Constant *CST = dyn_cast<Constant>(V);
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if (!CST)
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return None;
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// Holds a mapping from a global value number to a Constant.
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DenseMap<unsigned, Constant *>::iterator GVNToConstantIt;
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bool Inserted;
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// If we have a constant, try to make a new entry in the GVNToConstant.
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std::tie(GVNToConstantIt, Inserted) =
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GVNToConstant.insert(std::make_pair(GVN, CST));
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// If it was found and is not equal, it is not the same. We do not
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// handle this case yet, and exit early.
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if (Inserted || (GVNToConstantIt->second == CST))
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return true;
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return false;
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}
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/// Find whether \p Region matches the global value numbering to Constant
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/// mapping found so far.
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///
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/// \param Region - The OutlinableRegion we are checking for constants
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/// \param GVNToConstant - The mapping of global value number to Constants.
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/// \param NotSame - The set of global value numbers that do not have the same
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/// constant in each region.
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/// \returns true if all Constants are the same in every use of a Constant in \p
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/// Region and false if not
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static bool
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collectRegionsConstants(OutlinableRegion &Region,
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DenseMap<unsigned, Constant *> &GVNToConstant,
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DenseSet<unsigned> &NotSame) {
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bool ConstantsTheSame = true;
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IRSimilarityCandidate &C = *Region.Candidate;
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for (IRInstructionData &ID : C) {
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// Iterate over the operands in an instruction. If the global value number,
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// assigned by the IRSimilarityCandidate, has been seen before, we check if
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// the the number has been found to be not the same value in each instance.
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for (Value *V : ID.OperVals) {
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Optional<unsigned> GVNOpt = C.getGVN(V);
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assert(GVNOpt.hasValue() && "Expected a GVN for operand?");
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unsigned GVN = GVNOpt.getValue();
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// Check if this global value has been found to not be the same already.
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if (NotSame.find(GVN) != NotSame.end()) {
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if (isa<Constant>(V))
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ConstantsTheSame = false;
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continue;
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}
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// If it has been the same so far, we check the value for if the
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// associated Constant value match the previous instances of the same
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// global value number. If the global value does not map to a Constant,
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// it is considered to not be the same value.
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Optional<bool> ConstantMatches = constantMatches(V, GVN, GVNToConstant);
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if (ConstantMatches.hasValue()) {
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if (ConstantMatches.getValue())
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continue;
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else
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ConstantsTheSame = false;
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}
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// While this value is a register, it might not have been previously,
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// make sure we don't already have a constant mapped to this global value
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// number.
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if (GVNToConstant.find(GVN) != GVNToConstant.end())
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ConstantsTheSame = false;
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NotSame.insert(GVN);
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}
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}
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return ConstantsTheSame;
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}
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void OutlinableGroup::findSameConstants(DenseSet<unsigned> &NotSame) {
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DenseMap<unsigned, Constant *> GVNToConstant;
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for (OutlinableRegion *Region : Regions)
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collectRegionsConstants(*Region, GVNToConstant, NotSame);
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}
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Function *IROutliner::createFunction(Module &M, OutlinableGroup &Group,
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unsigned FunctionNameSuffix) {
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assert(!Group.OutlinedFunction && "Function is already defined!");
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Group.OutlinedFunctionType = FunctionType::get(
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Type::getVoidTy(M.getContext()), Group.ArgumentTypes, false);
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// These functions will only be called from within the same module, so
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// we can set an internal linkage.
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Group.OutlinedFunction = Function::Create(
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Group.OutlinedFunctionType, GlobalValue::InternalLinkage,
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"outlined_ir_func_" + std::to_string(FunctionNameSuffix), M);
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Group.OutlinedFunction->addFnAttr(Attribute::OptimizeForSize);
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Group.OutlinedFunction->addFnAttr(Attribute::MinSize);
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return Group.OutlinedFunction;
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}
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/// Move each BasicBlock in \p Old to \p New.
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///
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/// \param [in] Old - the function to move the basic blocks from.
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/// \param [in] New - The function to move the basic blocks to.
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/// \returns the first return block for the function in New.
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static BasicBlock *moveFunctionData(Function &Old, Function &New) {
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Function::iterator CurrBB, NextBB, FinalBB;
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BasicBlock *NewEnd = nullptr;
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std::vector<Instruction *> DebugInsts;
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for (CurrBB = Old.begin(), FinalBB = Old.end(); CurrBB != FinalBB;
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CurrBB = NextBB) {
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NextBB = std::next(CurrBB);
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CurrBB->removeFromParent();
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CurrBB->insertInto(&New);
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Instruction *I = CurrBB->getTerminator();
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if (isa<ReturnInst>(I))
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NewEnd = &(*CurrBB);
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}
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assert(NewEnd && "No return instruction for new function?");
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return NewEnd;
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}
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/// Find the the constants that will need to be lifted into arguments
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/// as they are not the same in each instance of the region.
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///
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/// \param [in] C - The IRSimilarityCandidate containing the region we are
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/// analyzing.
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/// \param [in] NotSame - The set of global value numbers that do not have a
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/// single Constant across all OutlinableRegions similar to \p C.
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/// \param [out] Inputs - The list containing the global value numbers of the
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/// arguments needed for the region of code.
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static void findConstants(IRSimilarityCandidate &C, DenseSet<unsigned> &NotSame,
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std::vector<unsigned> &Inputs) {
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DenseSet<unsigned> Seen;
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// Iterate over the instructions, and find what constants will need to be
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// extracted into arguments.
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for (IRInstructionDataList::iterator IDIt = C.begin(), EndIDIt = C.end();
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IDIt != EndIDIt; IDIt++) {
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for (Value *V : (*IDIt).OperVals) {
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// Since these are stored before any outlining, they will be in the
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// global value numbering.
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unsigned GVN = C.getGVN(V).getValue();
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if (isa<Constant>(V))
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if (NotSame.find(GVN) != NotSame.end() &&
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Seen.find(GVN) == Seen.end()) {
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Inputs.push_back(GVN);
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Seen.insert(GVN);
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}
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}
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}
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}
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/// Find the GVN for the inputs that have been found by the CodeExtractor.
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///
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/// \param [in] C - The IRSimilarityCandidate containing the region we are
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/// analyzing.
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/// \param [in] CurrentInputs - The set of inputs found by the
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/// CodeExtractor.
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/// \param [out] EndInputNumbers - The global value numbers for the extracted
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/// arguments.
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/// \param [in] OutputMappings - The mapping of values that have been replaced
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/// by a new output value.
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/// \param [out] EndInputs - The global value numbers for the extracted
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/// arguments.
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static void mapInputsToGVNs(IRSimilarityCandidate &C,
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SetVector<Value *> &CurrentInputs,
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const DenseMap<Value *, Value *> &OutputMappings,
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std::vector<unsigned> &EndInputNumbers) {
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// Get the Global Value Number for each input. We check if the Value has been
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// replaced by a different value at output, and use the original value before
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// replacement.
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for (Value *Input : CurrentInputs) {
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assert(Input && "Have a nullptr as an input");
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if (OutputMappings.find(Input) != OutputMappings.end())
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Input = OutputMappings.find(Input)->second;
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assert(C.getGVN(Input).hasValue() &&
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"Could not find a numbering for the given input");
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EndInputNumbers.push_back(C.getGVN(Input).getValue());
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}
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}
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/// Find the original value for the \p ArgInput values if any one of them was
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/// replaced during a previous extraction.
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///
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/// \param [in] ArgInputs - The inputs to be extracted by the code extractor.
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/// \param [in] OutputMappings - The mapping of values that have been replaced
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/// by a new output value.
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/// \param [out] RemappedArgInputs - The remapped values according to
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/// \p OutputMappings that will be extracted.
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static void
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remapExtractedInputs(const ArrayRef<Value *> ArgInputs,
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const DenseMap<Value *, Value *> &OutputMappings,
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SetVector<Value *> &RemappedArgInputs) {
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// Get the global value number for each input that will be extracted as an
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// argument by the code extractor, remapping if needed for reloaded values.
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for (Value *Input : ArgInputs) {
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if (OutputMappings.find(Input) != OutputMappings.end())
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Input = OutputMappings.find(Input)->second;
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RemappedArgInputs.insert(Input);
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}
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}
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/// Find the input GVNs and the output values for a region of Instructions.
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/// Using the code extractor, we collect the inputs to the extracted function.
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///
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/// The \p Region can be identified as needing to be ignored in this function.
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/// It should be checked whether it should be ignored after a call to this
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/// function.
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///
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/// \param [in,out] Region - The region of code to be analyzed.
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/// \param [out] InputGVNs - The global value numbers for the extracted
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/// arguments.
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/// \param [in] NotSame - The global value numbers in the region that do not
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/// have the same constant value in the regions structurally similar to
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/// \p Region.
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/// \param [in] OutputMappings - The mapping of values that have been replaced
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/// by a new output value after extraction.
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/// \param [out] ArgInputs - The values of the inputs to the extracted function.
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/// \param [out] Outputs - The set of values extracted by the CodeExtractor
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/// as outputs.
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static void getCodeExtractorArguments(
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OutlinableRegion &Region, std::vector<unsigned> &InputGVNs,
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DenseSet<unsigned> &NotSame, DenseMap<Value *, Value *> &OutputMappings,
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SetVector<Value *> &ArgInputs, SetVector<Value *> &Outputs) {
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IRSimilarityCandidate &C = *Region.Candidate;
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// OverallInputs are the inputs to the region found by the CodeExtractor,
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// SinkCands and HoistCands are used by the CodeExtractor to find sunken
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// allocas of values whose lifetimes are contained completely within the
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// outlined region. PremappedInputs are the arguments found by the
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// CodeExtractor, removing conditions such as sunken allocas, but that
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// may need to be remapped due to the extracted output values replacing
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// the original values.
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SetVector<Value *> OverallInputs, PremappedInputs, SinkCands, HoistCands;
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// Use the code extractor to get the inputs and outputs, without sunken
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// allocas or removing llvm.assumes.
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CodeExtractor *CE = Region.CE;
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CE->findInputsOutputs(OverallInputs, Outputs, SinkCands);
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assert(Region.StartBB && "Region must have a start BasicBlock!");
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Function *OrigF = Region.StartBB->getParent();
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CodeExtractorAnalysisCache CEAC(*OrigF);
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BasicBlock *Dummy = nullptr;
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// The region may be ineligible due to VarArgs in the parent function. In this
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// case we ignore the region.
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if (!CE->isEligible()) {
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Region.IgnoreRegion = true;
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return;
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}
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// Find if any values are going to be sunk into the function when extracted
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CE->findAllocas(CEAC, SinkCands, HoistCands, Dummy);
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CE->findInputsOutputs(PremappedInputs, Outputs, SinkCands);
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// TODO: Support regions with sunken allocas: values whose lifetimes are
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// contained completely within the outlined region. These are not guaranteed
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// to be the same in every region, so we must elevate them all to arguments
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// when they appear. If these values are not equal, it means there is some
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// Input in OverallInputs that was removed for ArgInputs.
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if (OverallInputs.size() != PremappedInputs.size()) {
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Region.IgnoreRegion = true;
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return;
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}
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findConstants(C, NotSame, InputGVNs);
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mapInputsToGVNs(C, OverallInputs, OutputMappings, InputGVNs);
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remapExtractedInputs(PremappedInputs.getArrayRef(), OutputMappings,
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ArgInputs);
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// Sort the GVNs, since we now have constants included in the \ref InputGVNs
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// we need to make sure they are in a deterministic order.
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stable_sort(InputGVNs.begin(), InputGVNs.end());
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}
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/// Look over the inputs and map each input argument to an argument in the
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/// overall function for the OutlinableRegions. This creates a way to replace
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/// the arguments of the extracted function with the arguments of the new
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/// overall function.
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///
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|
/// \param [in,out] Region - The region of code to be analyzed.
|
|
/// \param [in] InputsGVNs - The global value numbering of the input values
|
|
/// collected.
|
|
/// \param [in] ArgInputs - The values of the arguments to the extracted
|
|
/// function.
|
|
static void
|
|
findExtractedInputToOverallInputMapping(OutlinableRegion &Region,
|
|
std::vector<unsigned> &InputGVNs,
|
|
SetVector<Value *> &ArgInputs) {
|
|
|
|
IRSimilarityCandidate &C = *Region.Candidate;
|
|
OutlinableGroup &Group = *Region.Parent;
|
|
|
|
// This counts the argument number in the overall function.
|
|
unsigned TypeIndex = 0;
|
|
|
|
// This counts the argument number in the extracted function.
|
|
unsigned OriginalIndex = 0;
|
|
|
|
// Find the mapping of the extracted arguments to the arguments for the
|
|
// overall function. Since there may be extra arguments in the overall
|
|
// function to account for the extracted constants, we have two different
|
|
// counters as we find extracted arguments, and as we come across overall
|
|
// arguments.
|
|
for (unsigned InputVal : InputGVNs) {
|
|
Optional<Value *> InputOpt = C.fromGVN(InputVal);
|
|
assert(InputOpt.hasValue() && "Global value number not found?");
|
|
Value *Input = InputOpt.getValue();
|
|
|
|
if (!Group.InputTypesSet)
|
|
Group.ArgumentTypes.push_back(Input->getType());
|
|
|
|
// Check if we have a constant. If we do add it to the overall argument
|
|
// number to Constant map for the region, and continue to the next input.
|
|
if (Constant *CST = dyn_cast<Constant>(Input)) {
|
|
Region.AggArgToConstant.insert(std::make_pair(TypeIndex, CST));
|
|
TypeIndex++;
|
|
continue;
|
|
}
|
|
|
|
// It is not a constant, we create the mapping from extracted argument list
|
|
// to the overall argument list.
|
|
assert(ArgInputs.count(Input) && "Input cannot be found!");
|
|
|
|
Region.ExtractedArgToAgg.insert(std::make_pair(OriginalIndex, TypeIndex));
|
|
Region.AggArgToExtracted.insert(std::make_pair(TypeIndex, OriginalIndex));
|
|
OriginalIndex++;
|
|
TypeIndex++;
|
|
}
|
|
|
|
// If the function type definitions for the OutlinableGroup holding the region
|
|
// have not been set, set the length of the inputs here. We should have the
|
|
// same inputs for all of the different regions contained in the
|
|
// OutlinableGroup since they are all structurally similar to one another.
|
|
if (!Group.InputTypesSet) {
|
|
Group.NumAggregateInputs = TypeIndex;
|
|
Group.InputTypesSet = true;
|
|
}
|
|
|
|
Region.NumExtractedInputs = OriginalIndex;
|
|
}
|
|
|
|
/// Create a mapping of the output arguments for the \p Region to the output
|
|
/// arguments of the overall outlined function.
|
|
///
|
|
/// \param [in,out] Region - The region of code to be analyzed.
|
|
/// \param [in] Outputs - The values found by the code extractor.
|
|
static void
|
|
findExtractedOutputToOverallOutputMapping(OutlinableRegion &Region,
|
|
ArrayRef<Value *> Outputs) {
|
|
OutlinableGroup &Group = *Region.Parent;
|
|
IRSimilarityCandidate &C = *Region.Candidate;
|
|
|
|
// This counts the argument number in the extracted function.
|
|
unsigned OriginalIndex = Region.NumExtractedInputs;
|
|
|
|
// This counts the argument number in the overall function.
|
|
unsigned TypeIndex = Group.NumAggregateInputs;
|
|
bool TypeFound;
|
|
DenseSet<unsigned> AggArgsUsed;
|
|
|
|
// Iterate over the output types and identify if there is an aggregate pointer
|
|
// type whose base type matches the current output type. If there is, we mark
|
|
// that we will use this output register for this value. If not we add another
|
|
// type to the overall argument type list. We also store the GVNs used for
|
|
// stores to identify which values will need to be moved into an special
|
|
// block that holds the stores to the output registers.
|
|
for (Value *Output : Outputs) {
|
|
TypeFound = false;
|
|
// We can do this since it is a result value, and will have a number
|
|
// that is necessarily the same. BUT if in the future, the instructions
|
|
// do not have to be in same order, but are functionally the same, we will
|
|
// have to use a different scheme, as one-to-one correspondence is not
|
|
// guaranteed.
|
|
unsigned GlobalValue = C.getGVN(Output).getValue();
|
|
unsigned ArgumentSize = Group.ArgumentTypes.size();
|
|
|
|
for (unsigned Jdx = TypeIndex; Jdx < ArgumentSize; Jdx++) {
|
|
if (Group.ArgumentTypes[Jdx] != PointerType::getUnqual(Output->getType()))
|
|
continue;
|
|
|
|
if (AggArgsUsed.find(Jdx) != AggArgsUsed.end())
|
|
continue;
|
|
|
|
TypeFound = true;
|
|
AggArgsUsed.insert(Jdx);
|
|
Region.ExtractedArgToAgg.insert(std::make_pair(OriginalIndex, Jdx));
|
|
Region.AggArgToExtracted.insert(std::make_pair(Jdx, OriginalIndex));
|
|
Region.GVNStores.push_back(GlobalValue);
|
|
break;
|
|
}
|
|
|
|
// We were unable to find an unused type in the output type set that matches
|
|
// the output, so we add a pointer type to the argument types of the overall
|
|
// function to handle this output and create a mapping to it.
|
|
if (!TypeFound) {
|
|
Group.ArgumentTypes.push_back(PointerType::getUnqual(Output->getType()));
|
|
AggArgsUsed.insert(Group.ArgumentTypes.size() - 1);
|
|
Region.ExtractedArgToAgg.insert(
|
|
std::make_pair(OriginalIndex, Group.ArgumentTypes.size() - 1));
|
|
Region.AggArgToExtracted.insert(
|
|
std::make_pair(Group.ArgumentTypes.size() - 1, OriginalIndex));
|
|
Region.GVNStores.push_back(GlobalValue);
|
|
}
|
|
|
|
stable_sort(Region.GVNStores);
|
|
OriginalIndex++;
|
|
TypeIndex++;
|
|
}
|
|
}
|
|
|
|
void IROutliner::findAddInputsOutputs(Module &M, OutlinableRegion &Region,
|
|
DenseSet<unsigned> &NotSame) {
|
|
std::vector<unsigned> Inputs;
|
|
SetVector<Value *> ArgInputs, Outputs;
|
|
|
|
getCodeExtractorArguments(Region, Inputs, NotSame, OutputMappings, ArgInputs,
|
|
Outputs);
|
|
|
|
if (Region.IgnoreRegion)
|
|
return;
|
|
|
|
// Map the inputs found by the CodeExtractor to the arguments found for
|
|
// the overall function.
|
|
findExtractedInputToOverallInputMapping(Region, Inputs, ArgInputs);
|
|
|
|
// Map the outputs found by the CodeExtractor to the arguments found for
|
|
// the overall function.
|
|
findExtractedOutputToOverallOutputMapping(Region, Outputs.getArrayRef());
|
|
}
|
|
|
|
/// Replace the extracted function in the Region with a call to the overall
|
|
/// function constructed from the deduplicated similar regions, replacing and
|
|
/// remapping the values passed to the extracted function as arguments to the
|
|
/// new arguments of the overall function.
|
|
///
|
|
/// \param [in] M - The module to outline from.
|
|
/// \param [in] Region - The regions of extracted code to be replaced with a new
|
|
/// function.
|
|
/// \returns a call instruction with the replaced function.
|
|
CallInst *replaceCalledFunction(Module &M, OutlinableRegion &Region) {
|
|
std::vector<Value *> NewCallArgs;
|
|
DenseMap<unsigned, unsigned>::iterator ArgPair;
|
|
|
|
OutlinableGroup &Group = *Region.Parent;
|
|
CallInst *Call = Region.Call;
|
|
assert(Call && "Call to replace is nullptr?");
|
|
Function *AggFunc = Group.OutlinedFunction;
|
|
assert(AggFunc && "Function to replace with is nullptr?");
|
|
|
|
// If the arguments are the same size, there are not values that need to be
|
|
// made argument, or different output registers to handle. We can simply
|
|
// replace the called function in this case.
|
|
if (AggFunc->arg_size() == Call->arg_size()) {
|
|
LLVM_DEBUG(dbgs() << "Replace call to " << *Call << " with call to "
|
|
<< *AggFunc << " with same number of arguments\n");
|
|
Call->setCalledFunction(AggFunc);
|
|
return Call;
|
|
}
|
|
|
|
// We have a different number of arguments than the new function, so
|
|
// we need to use our previously mappings off extracted argument to overall
|
|
// function argument, and constants to overall function argument to create the
|
|
// new argument list.
|
|
for (unsigned AggArgIdx = 0; AggArgIdx < AggFunc->arg_size(); AggArgIdx++) {
|
|
|
|
if (AggArgIdx == AggFunc->arg_size() - 1 &&
|
|
Group.ArgumentTypes.size() > Group.NumAggregateInputs) {
|
|
// If we are on the last argument, and we need to differentiate between
|
|
// output blocks, add an integer to the argument list to determine
|
|
// what block to take
|
|
LLVM_DEBUG(dbgs() << "Set switch block argument to "
|
|
<< Region.OutputBlockNum << "\n");
|
|
NewCallArgs.push_back(ConstantInt::get(Type::getInt32Ty(M.getContext()),
|
|
Region.OutputBlockNum));
|
|
continue;
|
|
}
|
|
|
|
ArgPair = Region.AggArgToExtracted.find(AggArgIdx);
|
|
if (ArgPair != Region.AggArgToExtracted.end()) {
|
|
Value *ArgumentValue = Call->getArgOperand(ArgPair->second);
|
|
// If we found the mapping from the extracted function to the overall
|
|
// function, we simply add it to the argument list. We use the same
|
|
// value, it just needs to honor the new order of arguments.
|
|
LLVM_DEBUG(dbgs() << "Setting argument " << AggArgIdx << " to value "
|
|
<< *ArgumentValue << "\n");
|
|
NewCallArgs.push_back(ArgumentValue);
|
|
continue;
|
|
}
|
|
|
|
// If it is a constant, we simply add it to the argument list as a value.
|
|
if (Region.AggArgToConstant.find(AggArgIdx) !=
|
|
Region.AggArgToConstant.end()) {
|
|
Constant *CST = Region.AggArgToConstant.find(AggArgIdx)->second;
|
|
LLVM_DEBUG(dbgs() << "Setting argument " << AggArgIdx << " to value "
|
|
<< *CST << "\n");
|
|
NewCallArgs.push_back(CST);
|
|
continue;
|
|
}
|
|
|
|
// Add a nullptr value if the argument is not found in the extracted
|
|
// function. If we cannot find a value, it means it is not in use
|
|
// for the region, so we should not pass anything to it.
|
|
LLVM_DEBUG(dbgs() << "Setting argument " << AggArgIdx << " to nullptr\n");
|
|
NewCallArgs.push_back(ConstantPointerNull::get(
|
|
static_cast<PointerType *>(AggFunc->getArg(AggArgIdx)->getType())));
|
|
}
|
|
|
|
LLVM_DEBUG(dbgs() << "Replace call to " << *Call << " with call to "
|
|
<< *AggFunc << " with new set of arguments\n");
|
|
// Create the new call instruction and erase the old one.
|
|
Call = CallInst::Create(AggFunc->getFunctionType(), AggFunc, NewCallArgs, "",
|
|
Call);
|
|
|
|
// It is possible that the call to the outlined function is either the first
|
|
// instruction in the new block, the last instruction, or both. If either of
|
|
// these is the case, we need to make sure that we replace the instruction in
|
|
// the IRInstructionData struct with the new call.
|
|
CallInst *OldCall = Region.Call;
|
|
if (Region.NewFront->Inst == OldCall)
|
|
Region.NewFront->Inst = Call;
|
|
if (Region.NewBack->Inst == OldCall)
|
|
Region.NewBack->Inst = Call;
|
|
|
|
// Transfer any debug information.
|
|
Call->setDebugLoc(Region.Call->getDebugLoc());
|
|
|
|
// Remove the old instruction.
|
|
OldCall->eraseFromParent();
|
|
Region.Call = Call;
|
|
|
|
return Call;
|
|
}
|
|
|
|
// Within an extracted function, replace the argument uses of the extracted
|
|
// region with the arguments of the function for an OutlinableGroup.
|
|
//
|
|
/// \param [in] Region - The region of extracted code to be changed.
|
|
/// \param [in,out] OutputBB - The BasicBlock for the output stores for this
|
|
/// region.
|
|
static void replaceArgumentUses(OutlinableRegion &Region,
|
|
BasicBlock *OutputBB) {
|
|
OutlinableGroup &Group = *Region.Parent;
|
|
assert(Region.ExtractedFunction && "Region has no extracted function?");
|
|
|
|
for (unsigned ArgIdx = 0; ArgIdx < Region.ExtractedFunction->arg_size();
|
|
ArgIdx++) {
|
|
assert(Region.ExtractedArgToAgg.find(ArgIdx) !=
|
|
Region.ExtractedArgToAgg.end() &&
|
|
"No mapping from extracted to outlined?");
|
|
unsigned AggArgIdx = Region.ExtractedArgToAgg.find(ArgIdx)->second;
|
|
Argument *AggArg = Group.OutlinedFunction->getArg(AggArgIdx);
|
|
Argument *Arg = Region.ExtractedFunction->getArg(ArgIdx);
|
|
// The argument is an input, so we can simply replace it with the overall
|
|
// argument value
|
|
if (ArgIdx < Region.NumExtractedInputs) {
|
|
LLVM_DEBUG(dbgs() << "Replacing uses of input " << *Arg << " in function "
|
|
<< *Region.ExtractedFunction << " with " << *AggArg
|
|
<< " in function " << *Group.OutlinedFunction << "\n");
|
|
Arg->replaceAllUsesWith(AggArg);
|
|
continue;
|
|
}
|
|
|
|
// If we are replacing an output, we place the store value in its own
|
|
// block inside the overall function before replacing the use of the output
|
|
// in the function.
|
|
assert(Arg->hasOneUse() && "Output argument can only have one use");
|
|
User *InstAsUser = Arg->user_back();
|
|
assert(InstAsUser && "User is nullptr!");
|
|
|
|
Instruction *I = cast<Instruction>(InstAsUser);
|
|
I->setDebugLoc(DebugLoc());
|
|
LLVM_DEBUG(dbgs() << "Move store for instruction " << *I << " to "
|
|
<< *OutputBB << "\n");
|
|
|
|
I->moveBefore(*OutputBB, OutputBB->end());
|
|
|
|
LLVM_DEBUG(dbgs() << "Replacing uses of output " << *Arg << " in function "
|
|
<< *Region.ExtractedFunction << " with " << *AggArg
|
|
<< " in function " << *Group.OutlinedFunction << "\n");
|
|
Arg->replaceAllUsesWith(AggArg);
|
|
}
|
|
}
|
|
|
|
/// Within an extracted function, replace the constants that need to be lifted
|
|
/// into arguments with the actual argument.
|
|
///
|
|
/// \param Region [in] - The region of extracted code to be changed.
|
|
void replaceConstants(OutlinableRegion &Region) {
|
|
OutlinableGroup &Group = *Region.Parent;
|
|
// Iterate over the constants that need to be elevated into arguments
|
|
for (std::pair<unsigned, Constant *> &Const : Region.AggArgToConstant) {
|
|
unsigned AggArgIdx = Const.first;
|
|
Function *OutlinedFunction = Group.OutlinedFunction;
|
|
assert(OutlinedFunction && "Overall Function is not defined?");
|
|
Constant *CST = Const.second;
|
|
Argument *Arg = Group.OutlinedFunction->getArg(AggArgIdx);
|
|
// Identify the argument it will be elevated to, and replace instances of
|
|
// that constant in the function.
|
|
|
|
// TODO: If in the future constants do not have one global value number,
|
|
// i.e. a constant 1 could be mapped to several values, this check will
|
|
// have to be more strict. It cannot be using only replaceUsesWithIf.
|
|
|
|
LLVM_DEBUG(dbgs() << "Replacing uses of constant " << *CST
|
|
<< " in function " << *OutlinedFunction << " with "
|
|
<< *Arg << "\n");
|
|
CST->replaceUsesWithIf(Arg, [OutlinedFunction](Use &U) {
|
|
if (Instruction *I = dyn_cast<Instruction>(U.getUser()))
|
|
return I->getFunction() == OutlinedFunction;
|
|
return false;
|
|
});
|
|
}
|
|
}
|
|
|
|
/// For the given function, find all the nondebug or lifetime instructions,
|
|
/// and return them as a vector. Exclude any blocks in \p ExludeBlocks.
|
|
///
|
|
/// \param [in] F - The function we collect the instructions from.
|
|
/// \param [in] ExcludeBlocks - BasicBlocks to ignore.
|
|
/// \returns the list of instructions extracted.
|
|
static std::vector<Instruction *>
|
|
collectRelevantInstructions(Function &F,
|
|
DenseSet<BasicBlock *> &ExcludeBlocks) {
|
|
std::vector<Instruction *> RelevantInstructions;
|
|
|
|
for (BasicBlock &BB : F) {
|
|
if (ExcludeBlocks.find(&BB) != ExcludeBlocks.end())
|
|
continue;
|
|
|
|
for (Instruction &Inst : BB) {
|
|
if (Inst.isLifetimeStartOrEnd())
|
|
continue;
|
|
if (isa<DbgInfoIntrinsic>(Inst))
|
|
continue;
|
|
|
|
RelevantInstructions.push_back(&Inst);
|
|
}
|
|
}
|
|
|
|
return RelevantInstructions;
|
|
}
|
|
|
|
/// For the outlined section, move needed the StoreInsts for the output
|
|
/// registers into their own block. Then, determine if there is a duplicate
|
|
/// output block already created.
|
|
///
|
|
/// \param [in] OG - The OutlinableGroup of regions to be outlined.
|
|
/// \param [in] Region - The OutlinableRegion that is being analyzed.
|
|
/// \param [in,out] OutputBB - the block that stores for this region will be
|
|
/// placed in.
|
|
/// \param [in] EndBB - the final block of the extracted function.
|
|
/// \param [in] OutputMappings - OutputMappings the mapping of values that have
|
|
/// been replaced by a new output value.
|
|
/// \param [in,out] OutputStoreBBs - The existing output blocks.
|
|
static void
|
|
alignOutputBlockWithAggFunc(OutlinableGroup &OG, OutlinableRegion &Region,
|
|
BasicBlock *OutputBB, BasicBlock *EndBB,
|
|
const DenseMap<Value *, Value *> &OutputMappings,
|
|
std::vector<BasicBlock *> &OutputStoreBBs) {
|
|
DenseSet<unsigned> ValuesToFind(Region.GVNStores.begin(),
|
|
Region.GVNStores.end());
|
|
|
|
// We iterate over the instructions in the extracted function, and find the
|
|
// global value number of the instructions. If we find a value that should
|
|
// be contained in a store, we replace the uses of the value with the value
|
|
// from the overall function, so that the store is storing the correct
|
|
// value from the overall function.
|
|
|
|
DenseSet<BasicBlock *> ExcludeBBs(OutputStoreBBs.begin(),
|
|
OutputStoreBBs.end());
|
|
std::vector<Instruction *> ExtractedFunctionInsts =
|
|
collectRelevantInstructions(*(Region.ExtractedFunction), ExcludeBBs);
|
|
std::vector<Instruction *> OverallFunctionInsts =
|
|
collectRelevantInstructions(*OG.OutlinedFunction, ExcludeBBs);
|
|
|
|
assert(ExtractedFunctionInsts.size() == OverallFunctionInsts.size() &&
|
|
"Number of relevant instructions not equal!");
|
|
|
|
unsigned NumInstructions = ExtractedFunctionInsts.size();
|
|
for (unsigned Idx = 0; Idx < NumInstructions; Idx++) {
|
|
Value *V = ExtractedFunctionInsts[Idx];
|
|
|
|
if (OutputMappings.find(V) != OutputMappings.end())
|
|
V = OutputMappings.find(V)->second;
|
|
Optional<unsigned> GVN = Region.Candidate->getGVN(V);
|
|
|
|
// If we have found one of the stored values for output, replace the value
|
|
// with the corresponding one from the overall function.
|
|
if (GVN.hasValue() &&
|
|
ValuesToFind.find(GVN.getValue()) != ValuesToFind.end()) {
|
|
ValuesToFind.erase(GVN.getValue());
|
|
V->replaceAllUsesWith(OverallFunctionInsts[Idx]);
|
|
if (ValuesToFind.size() == 0)
|
|
break;
|
|
}
|
|
|
|
if (ValuesToFind.size() == 0)
|
|
break;
|
|
}
|
|
|
|
assert(ValuesToFind.size() == 0 && "Not all store values were handled!");
|
|
}
|
|
|
|
/// Create the switch statement for outlined function to differentiate between
|
|
/// all the output blocks.
|
|
///
|
|
/// For the outlined section, determine if an outlined block already exists that
|
|
/// matches the needed stores for the extracted section.
|
|
/// \param [in] M - The module we are outlining from.
|
|
/// \param [in] OG - The group of regions to be outlined.
|
|
/// \param [in] OS - The region that is being analyzed.
|
|
/// \param [in] EndBB - The final block of the extracted function.
|
|
/// \param [in,out] OutputStoreBBs - The existing output blocks.
|
|
void createSwitchStatement(Module &M, OutlinableGroup &OG, BasicBlock *EndBB,
|
|
ArrayRef<BasicBlock *> OutputStoreBBs) {
|
|
Function *AggFunc = OG.OutlinedFunction;
|
|
// Create a final block
|
|
BasicBlock *ReturnBlock =
|
|
BasicBlock::Create(M.getContext(), "final_block", AggFunc);
|
|
Instruction *Term = EndBB->getTerminator();
|
|
Term->moveBefore(*ReturnBlock, ReturnBlock->end());
|
|
// Put the switch statement in the old end basic block for the function with
|
|
// a fall through to the new return block
|
|
LLVM_DEBUG(dbgs() << "Create switch statement in " << *AggFunc << " for "
|
|
<< OutputStoreBBs.size() << "\n");
|
|
SwitchInst *SwitchI =
|
|
SwitchInst::Create(AggFunc->getArg(AggFunc->arg_size() - 1), ReturnBlock,
|
|
OutputStoreBBs.size(), EndBB);
|
|
|
|
unsigned Idx = 0;
|
|
for (BasicBlock *BB : OutputStoreBBs) {
|
|
SwitchI->addCase(ConstantInt::get(Type::getInt32Ty(M.getContext()), Idx),
|
|
BB);
|
|
Term = BB->getTerminator();
|
|
Term->setSuccessor(0, ReturnBlock);
|
|
Idx++;
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
/// Fill the new function that will serve as the replacement function for all of
|
|
/// the extracted regions of a certain structure from the first region in the
|
|
/// list of regions. Replace this first region's extracted function with the
|
|
/// new overall function.
|
|
///
|
|
/// \param [in] M - The module we are outlining from.
|
|
/// \param [in] CurrentGroup - The group of regions to be outlined.
|
|
/// \param [in,out] OutputStoreBBs - The output blocks for each different
|
|
/// set of stores needed for the different functions.
|
|
/// \param [in,out] FuncsToRemove - Extracted functions to erase from module
|
|
/// once outlining is complete.
|
|
static void fillOverallFunction(Module &M, OutlinableGroup &CurrentGroup,
|
|
std::vector<BasicBlock *> &OutputStoreBBs,
|
|
std::vector<Function *> &FuncsToRemove) {
|
|
OutlinableRegion *CurrentOS = CurrentGroup.Regions[0];
|
|
|
|
// Move first extracted function's instructions into new function.
|
|
LLVM_DEBUG(dbgs() << "Move instructions from "
|
|
<< *CurrentOS->ExtractedFunction << " to instruction "
|
|
<< *CurrentGroup.OutlinedFunction << "\n");
|
|
|
|
CurrentGroup.EndBB = moveFunctionData(*CurrentOS->ExtractedFunction,
|
|
*CurrentGroup.OutlinedFunction);
|
|
|
|
// Transfer the attributes from the function to the new function.
|
|
for (Attribute A :
|
|
CurrentOS->ExtractedFunction->getAttributes().getFnAttributes())
|
|
CurrentGroup.OutlinedFunction->addFnAttr(A);
|
|
|
|
// Create an output block for the first extracted function.
|
|
BasicBlock *NewBB = BasicBlock::Create(
|
|
M.getContext(), Twine("output_block_") + Twine(static_cast<unsigned>(0)),
|
|
CurrentGroup.OutlinedFunction);
|
|
CurrentOS->OutputBlockNum = 0;
|
|
|
|
replaceArgumentUses(*CurrentOS, NewBB);
|
|
replaceConstants(*CurrentOS);
|
|
|
|
if (CurrentGroup.ArgumentTypes.size() > CurrentGroup.NumAggregateInputs) {
|
|
BranchInst::Create(CurrentGroup.EndBB, NewBB);
|
|
OutputStoreBBs.push_back(NewBB);
|
|
} else
|
|
NewBB->eraseFromParent();
|
|
|
|
// Replace the call to the extracted function with the outlined function.
|
|
CurrentOS->Call = replaceCalledFunction(M, *CurrentOS);
|
|
|
|
// We only delete the extracted functions at the end since we may need to
|
|
// reference instructions contained in them for mapping purposes.
|
|
FuncsToRemove.push_back(CurrentOS->ExtractedFunction);
|
|
}
|
|
|
|
void IROutliner::deduplicateExtractedSections(
|
|
Module &M, OutlinableGroup &CurrentGroup,
|
|
std::vector<Function *> &FuncsToRemove, unsigned &OutlinedFunctionNum) {
|
|
createFunction(M, CurrentGroup, OutlinedFunctionNum);
|
|
|
|
std::vector<BasicBlock *> OutputStoreBBs;
|
|
|
|
OutlinableRegion *CurrentOS;
|
|
|
|
fillOverallFunction(M, CurrentGroup, OutputStoreBBs, FuncsToRemove);
|
|
|
|
for (unsigned Idx = 1; Idx < CurrentGroup.Regions.size(); Idx++) {
|
|
CurrentOS = CurrentGroup.Regions[Idx];
|
|
|
|
// Create a new BasicBlock to hold the needed store instructions.
|
|
BasicBlock *NewBB = BasicBlock::Create(
|
|
M.getContext(), "output_block_" + std::to_string(Idx),
|
|
CurrentGroup.OutlinedFunction);
|
|
replaceArgumentUses(*CurrentOS, NewBB);
|
|
|
|
if (CurrentGroup.ArgumentTypes.size() > CurrentGroup.NumAggregateInputs) {
|
|
BranchInst::Create(CurrentGroup.EndBB, NewBB);
|
|
CurrentOS->OutputBlockNum = OutputStoreBBs.size();
|
|
OutputStoreBBs.push_back(NewBB);
|
|
alignOutputBlockWithAggFunc(CurrentGroup, *CurrentOS, NewBB,
|
|
CurrentGroup.EndBB, OutputMappings,
|
|
OutputStoreBBs);
|
|
} else
|
|
NewBB->eraseFromParent();
|
|
|
|
CurrentOS->Call = replaceCalledFunction(M, *CurrentOS);
|
|
FuncsToRemove.push_back(CurrentOS->ExtractedFunction);
|
|
}
|
|
|
|
// Create a switch statement to handle the different output schemes.
|
|
if (CurrentGroup.ArgumentTypes.size() > CurrentGroup.NumAggregateInputs)
|
|
createSwitchStatement(M, CurrentGroup, CurrentGroup.EndBB, OutputStoreBBs);
|
|
|
|
OutlinedFunctionNum++;
|
|
}
|
|
|
|
void IROutliner::pruneIncompatibleRegions(
|
|
std::vector<IRSimilarityCandidate> &CandidateVec,
|
|
OutlinableGroup &CurrentGroup) {
|
|
bool PreviouslyOutlined;
|
|
|
|
// Sort from beginning to end, so the IRSimilarityCandidates are in order.
|
|
stable_sort(CandidateVec, [](const IRSimilarityCandidate &LHS,
|
|
const IRSimilarityCandidate &RHS) {
|
|
return LHS.getStartIdx() < RHS.getStartIdx();
|
|
});
|
|
|
|
unsigned CurrentEndIdx = 0;
|
|
for (IRSimilarityCandidate &IRSC : CandidateVec) {
|
|
PreviouslyOutlined = false;
|
|
unsigned StartIdx = IRSC.getStartIdx();
|
|
unsigned EndIdx = IRSC.getEndIdx();
|
|
|
|
for (unsigned Idx = StartIdx; Idx <= EndIdx; Idx++)
|
|
if (Outlined.contains(Idx)) {
|
|
PreviouslyOutlined = true;
|
|
break;
|
|
}
|
|
|
|
if (PreviouslyOutlined)
|
|
continue;
|
|
|
|
// TODO: If in the future we can outline across BasicBlocks, we will need to
|
|
// check all BasicBlocks contained in the region.
|
|
if (IRSC.getStartBB()->hasAddressTaken())
|
|
continue;
|
|
|
|
// Greedily prune out any regions that will overlap with already chosen
|
|
// regions.
|
|
if (CurrentEndIdx != 0 && StartIdx <= CurrentEndIdx)
|
|
continue;
|
|
|
|
bool BadInst = any_of(IRSC, [this](IRInstructionData &ID) {
|
|
return !this->InstructionClassifier.visit(ID.Inst);
|
|
});
|
|
|
|
if (BadInst)
|
|
continue;
|
|
|
|
OutlinableRegion *OS = new (RegionAllocator.Allocate())
|
|
OutlinableRegion(IRSC, CurrentGroup);
|
|
CurrentGroup.Regions.push_back(OS);
|
|
|
|
CurrentEndIdx = EndIdx;
|
|
}
|
|
}
|
|
|
|
void IROutliner::updateOutputMapping(OutlinableRegion &Region,
|
|
ArrayRef<Value *> Outputs,
|
|
LoadInst *LI) {
|
|
// For and load instructions following the call
|
|
Value *Operand = LI->getPointerOperand();
|
|
Optional<unsigned> OutputIdx = None;
|
|
// Find if the operand it is an output register.
|
|
for (unsigned ArgIdx = Region.NumExtractedInputs;
|
|
ArgIdx < Region.Call->arg_size(); ArgIdx++) {
|
|
if (Operand == Region.Call->getArgOperand(ArgIdx)) {
|
|
OutputIdx = ArgIdx - Region.NumExtractedInputs;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If we found an output register, place a mapping of the new value
|
|
// to the original in the mapping.
|
|
if (!OutputIdx.hasValue())
|
|
return;
|
|
|
|
if (OutputMappings.find(Outputs[OutputIdx.getValue()]) ==
|
|
OutputMappings.end()) {
|
|
LLVM_DEBUG(dbgs() << "Mapping extracted output " << *LI << " to "
|
|
<< *Outputs[OutputIdx.getValue()] << "\n");
|
|
OutputMappings.insert(std::make_pair(LI, Outputs[OutputIdx.getValue()]));
|
|
} else {
|
|
Value *Orig = OutputMappings.find(Outputs[OutputIdx.getValue()])->second;
|
|
LLVM_DEBUG(dbgs() << "Mapping extracted output " << *Orig << " to "
|
|
<< *Outputs[OutputIdx.getValue()] << "\n");
|
|
OutputMappings.insert(std::make_pair(LI, Orig));
|
|
}
|
|
}
|
|
|
|
bool IROutliner::extractSection(OutlinableRegion &Region) {
|
|
SetVector<Value *> ArgInputs, Outputs, SinkCands;
|
|
Region.CE->findInputsOutputs(ArgInputs, Outputs, SinkCands);
|
|
|
|
assert(Region.StartBB && "StartBB for the OutlinableRegion is nullptr!");
|
|
assert(Region.FollowBB && "FollowBB for the OutlinableRegion is nullptr!");
|
|
Function *OrigF = Region.StartBB->getParent();
|
|
CodeExtractorAnalysisCache CEAC(*OrigF);
|
|
Region.ExtractedFunction = Region.CE->extractCodeRegion(CEAC);
|
|
|
|
// If the extraction was successful, find the BasicBlock, and reassign the
|
|
// OutlinableRegion blocks
|
|
if (!Region.ExtractedFunction) {
|
|
LLVM_DEBUG(dbgs() << "CodeExtractor failed to outline " << Region.StartBB
|
|
<< "\n");
|
|
Region.reattachCandidate();
|
|
return false;
|
|
}
|
|
|
|
BasicBlock *RewrittenBB = Region.FollowBB->getSinglePredecessor();
|
|
Region.StartBB = RewrittenBB;
|
|
Region.EndBB = RewrittenBB;
|
|
|
|
// The sequences of outlinable regions has now changed. We must fix the
|
|
// IRInstructionDataList for consistency. Although they may not be illegal
|
|
// instructions, they should not be compared with anything else as they
|
|
// should not be outlined in this round. So marking these as illegal is
|
|
// allowed.
|
|
IRInstructionDataList *IDL = Region.Candidate->front()->IDL;
|
|
Instruction *BeginRewritten = &*RewrittenBB->begin();
|
|
Instruction *EndRewritten = &*RewrittenBB->begin();
|
|
Region.NewFront = new (InstDataAllocator.Allocate()) IRInstructionData(
|
|
*BeginRewritten, InstructionClassifier.visit(*BeginRewritten), *IDL);
|
|
Region.NewBack = new (InstDataAllocator.Allocate()) IRInstructionData(
|
|
*EndRewritten, InstructionClassifier.visit(*EndRewritten), *IDL);
|
|
|
|
// Insert the first IRInstructionData of the new region in front of the
|
|
// first IRInstructionData of the IRSimilarityCandidate.
|
|
IDL->insert(Region.Candidate->begin(), *Region.NewFront);
|
|
// Insert the first IRInstructionData of the new region after the
|
|
// last IRInstructionData of the IRSimilarityCandidate.
|
|
IDL->insert(Region.Candidate->end(), *Region.NewBack);
|
|
// Remove the IRInstructionData from the IRSimilarityCandidate.
|
|
IDL->erase(Region.Candidate->begin(), std::prev(Region.Candidate->end()));
|
|
|
|
assert(RewrittenBB != nullptr &&
|
|
"Could not find a predecessor after extraction!");
|
|
|
|
// Iterate over the new set of instructions to find the new call
|
|
// instruction.
|
|
for (Instruction &I : *RewrittenBB)
|
|
if (CallInst *CI = dyn_cast<CallInst>(&I)) {
|
|
if (Region.ExtractedFunction == CI->getCalledFunction())
|
|
Region.Call = CI;
|
|
} else if (LoadInst *LI = dyn_cast<LoadInst>(&I))
|
|
updateOutputMapping(Region, Outputs.getArrayRef(), LI);
|
|
Region.reattachCandidate();
|
|
return true;
|
|
}
|
|
|
|
unsigned IROutliner::doOutline(Module &M) {
|
|
// Find the possible similarity sections.
|
|
IRSimilarityIdentifier &Identifier = getIRSI(M);
|
|
SimilarityGroupList &SimilarityCandidates = *Identifier.getSimilarity();
|
|
|
|
// Sort them by size of extracted sections
|
|
unsigned OutlinedFunctionNum = 0;
|
|
// If we only have one SimilarityGroup in SimilarityCandidates, we do not have
|
|
// to sort them by the potential number of instructions to be outlined
|
|
if (SimilarityCandidates.size() > 1)
|
|
llvm::stable_sort(SimilarityCandidates,
|
|
[](const std::vector<IRSimilarityCandidate> &LHS,
|
|
const std::vector<IRSimilarityCandidate> &RHS) {
|
|
return LHS[0].getLength() * LHS.size() >
|
|
RHS[0].getLength() * RHS.size();
|
|
});
|
|
|
|
DenseSet<unsigned> NotSame;
|
|
std::vector<Function *> FuncsToRemove;
|
|
// Iterate over the possible sets of similarity.
|
|
for (SimilarityGroup &CandidateVec : SimilarityCandidates) {
|
|
OutlinableGroup CurrentGroup;
|
|
|
|
// Remove entries that were previously outlined
|
|
pruneIncompatibleRegions(CandidateVec, CurrentGroup);
|
|
|
|
// We pruned the number of regions to 0 to 1, meaning that it's not worth
|
|
// trying to outlined since there is no compatible similar instance of this
|
|
// code.
|
|
if (CurrentGroup.Regions.size() < 2)
|
|
continue;
|
|
|
|
// Determine if there are any values that are the same constant throughout
|
|
// each section in the set.
|
|
NotSame.clear();
|
|
CurrentGroup.findSameConstants(NotSame);
|
|
|
|
if (CurrentGroup.IgnoreGroup)
|
|
continue;
|
|
|
|
// Create a CodeExtractor for each outlinable region. Identify inputs and
|
|
// outputs for each section using the code extractor and create the argument
|
|
// types for the Aggregate Outlining Function.
|
|
std::vector<OutlinableRegion *> OutlinedRegions;
|
|
for (OutlinableRegion *OS : CurrentGroup.Regions) {
|
|
// Break the outlinable region out of its parent BasicBlock into its own
|
|
// BasicBlocks (see function implementation).
|
|
OS->splitCandidate();
|
|
std::vector<BasicBlock *> BE = {OS->StartBB};
|
|
OS->CE = new (ExtractorAllocator.Allocate())
|
|
CodeExtractor(BE, nullptr, false, nullptr, nullptr, nullptr, false,
|
|
false, "outlined");
|
|
findAddInputsOutputs(M, *OS, NotSame);
|
|
if (!OS->IgnoreRegion)
|
|
OutlinedRegions.push_back(OS);
|
|
else
|
|
OS->reattachCandidate();
|
|
}
|
|
|
|
CurrentGroup.Regions = std::move(OutlinedRegions);
|
|
|
|
if (CurrentGroup.Regions.empty())
|
|
continue;
|
|
|
|
// We are adding an extracted argument to decide between which output path
|
|
// to use in the basic block. It is used in a switch statement and only
|
|
// needs to be an integer.
|
|
if (CurrentGroup.ArgumentTypes.size() > CurrentGroup.NumAggregateInputs)
|
|
CurrentGroup.ArgumentTypes.push_back(Type::getInt32Ty(M.getContext()));
|
|
|
|
// Create functions out of all the sections, and mark them as outlined.
|
|
OutlinedRegions.clear();
|
|
for (OutlinableRegion *OS : CurrentGroup.Regions) {
|
|
bool FunctionOutlined = extractSection(*OS);
|
|
if (FunctionOutlined) {
|
|
unsigned StartIdx = OS->Candidate->getStartIdx();
|
|
unsigned EndIdx = OS->Candidate->getEndIdx();
|
|
for (unsigned Idx = StartIdx; Idx <= EndIdx; Idx++)
|
|
Outlined.insert(Idx);
|
|
|
|
OutlinedRegions.push_back(OS);
|
|
}
|
|
}
|
|
|
|
CurrentGroup.Regions = std::move(OutlinedRegions);
|
|
|
|
if (CurrentGroup.Regions.empty())
|
|
continue;
|
|
|
|
deduplicateExtractedSections(M, CurrentGroup, FuncsToRemove,
|
|
OutlinedFunctionNum);
|
|
}
|
|
|
|
for (Function *F : FuncsToRemove)
|
|
F->eraseFromParent();
|
|
|
|
return OutlinedFunctionNum;
|
|
}
|
|
|
|
bool IROutliner::run(Module &M) { return doOutline(M) > 0; }
|
|
|
|
// Pass Manager Boilerplate
|
|
class IROutlinerLegacyPass : public ModulePass {
|
|
public:
|
|
static char ID;
|
|
IROutlinerLegacyPass() : ModulePass(ID) {
|
|
initializeIROutlinerLegacyPassPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.addRequired<TargetTransformInfoWrapperPass>();
|
|
AU.addRequired<IRSimilarityIdentifierWrapperPass>();
|
|
}
|
|
|
|
bool runOnModule(Module &M) override;
|
|
};
|
|
|
|
bool IROutlinerLegacyPass::runOnModule(Module &M) {
|
|
if (skipModule(M))
|
|
return false;
|
|
|
|
auto GTTI = [this](Function &F) -> TargetTransformInfo & {
|
|
return this->getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
|
|
};
|
|
|
|
auto GIRSI = [this](Module &) -> IRSimilarityIdentifier & {
|
|
return this->getAnalysis<IRSimilarityIdentifierWrapperPass>().getIRSI();
|
|
};
|
|
|
|
return IROutliner(GTTI, GIRSI).run(M);
|
|
}
|
|
|
|
PreservedAnalyses IROutlinerPass::run(Module &M, ModuleAnalysisManager &AM) {
|
|
auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
|
|
|
|
std::function<TargetTransformInfo &(Function &)> GTTI =
|
|
[&FAM](Function &F) -> TargetTransformInfo & {
|
|
return FAM.getResult<TargetIRAnalysis>(F);
|
|
};
|
|
|
|
std::function<IRSimilarityIdentifier &(Module &)> GIRSI =
|
|
[&AM](Module &M) -> IRSimilarityIdentifier & {
|
|
return AM.getResult<IRSimilarityAnalysis>(M);
|
|
};
|
|
|
|
if (IROutliner(GTTI, GIRSI).run(M))
|
|
return PreservedAnalyses::none();
|
|
return PreservedAnalyses::all();
|
|
}
|
|
|
|
char IROutlinerLegacyPass::ID = 0;
|
|
INITIALIZE_PASS_BEGIN(IROutlinerLegacyPass, "iroutliner", "IR Outliner", false,
|
|
false)
|
|
INITIALIZE_PASS_DEPENDENCY(IRSimilarityIdentifierWrapperPass)
|
|
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
|
|
INITIALIZE_PASS_END(IROutlinerLegacyPass, "iroutliner", "IR Outliner", false,
|
|
false)
|
|
|
|
ModulePass *llvm::createIROutlinerPass() { return new IROutlinerLegacyPass(); }
|