3daf7ddaef
Before, the isPreLegalize() query in CombinerHelper only checked for the presence of a LegalizerInfo object. This is problematic when we want to have a combine actually check for legality in a pre-legalizer combine pass, since if we pass a LegalizerInfo object to the constructor it causes the combines to think that we're running *post* legalizer, which isn't true. This change fixes it to instead check an explicit bool that passes to signal whether the pass will be run before or after legalization. Doing so exposed a bug in the extending loads combine, which tried to check for legality of candidate extending loads if LegalizerInfo was present. Since we only ran it pre-legalizer and therefore with a null LegalizerInfo, it never actually ran. Also fixes the legality checks to keep the tests passing. Differential Revision: https://reviews.llvm.org/D135044
120 lines
4.0 KiB
C++
120 lines
4.0 KiB
C++
//=== lib/CodeGen/GlobalISel/MipsPreLegalizerCombiner.cpp --------------===//
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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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// This pass does combining of machine instructions at the generic MI level,
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// before the legalizer.
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//
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//===----------------------------------------------------------------------===//
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#include "MipsTargetMachine.h"
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#include "llvm/CodeGen/GlobalISel/Combiner.h"
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#include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
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#include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
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#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
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#include "llvm/CodeGen/MachineFunctionPass.h"
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#include "llvm/CodeGen/TargetPassConfig.h"
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#include "llvm/InitializePasses.h"
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#define DEBUG_TYPE "mips-prelegalizer-combiner"
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using namespace llvm;
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namespace {
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class MipsPreLegalizerCombinerInfo : public CombinerInfo {
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public:
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MipsPreLegalizerCombinerInfo()
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: CombinerInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
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/*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
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/*EnableOptSize*/ false, /*EnableMinSize*/ false) {}
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bool combine(GISelChangeObserver &Observer, MachineInstr &MI,
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MachineIRBuilder &B) const override;
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};
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bool MipsPreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
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MachineInstr &MI,
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MachineIRBuilder &B) const {
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CombinerHelper Helper(Observer, B, /*IsPreLegalize*/ true);
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switch (MI.getOpcode()) {
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default:
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return false;
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case TargetOpcode::G_MEMCPY_INLINE:
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return Helper.tryEmitMemcpyInline(MI);
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case TargetOpcode::G_LOAD:
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case TargetOpcode::G_SEXTLOAD:
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case TargetOpcode::G_ZEXTLOAD: {
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// Don't attempt to combine non power of 2 loads or unaligned loads when
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// subtarget doesn't support them.
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auto MMO = *MI.memoperands_begin();
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const MipsSubtarget &STI = MI.getMF()->getSubtarget<MipsSubtarget>();
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if (!isPowerOf2_64(MMO->getSize()))
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return false;
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bool isUnaligned = MMO->getAlign() < MMO->getSize();
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if (!STI.systemSupportsUnalignedAccess() && isUnaligned)
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return false;
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return Helper.tryCombineExtendingLoads(MI);
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}
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}
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return false;
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}
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// Pass boilerplate
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// ================
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class MipsPreLegalizerCombiner : public MachineFunctionPass {
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public:
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static char ID;
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MipsPreLegalizerCombiner();
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StringRef getPassName() const override { return "MipsPreLegalizerCombiner"; }
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bool runOnMachineFunction(MachineFunction &MF) override;
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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};
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} // end anonymous namespace
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void MipsPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<TargetPassConfig>();
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AU.setPreservesCFG();
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getSelectionDAGFallbackAnalysisUsage(AU);
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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MipsPreLegalizerCombiner::MipsPreLegalizerCombiner() : MachineFunctionPass(ID) {
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initializeMipsPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
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}
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bool MipsPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
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if (MF.getProperties().hasProperty(
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MachineFunctionProperties::Property::FailedISel))
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return false;
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auto *TPC = &getAnalysis<TargetPassConfig>();
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MipsPreLegalizerCombinerInfo PCInfo;
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Combiner C(PCInfo, TPC);
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return C.combineMachineInstrs(MF, nullptr);
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}
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char MipsPreLegalizerCombiner::ID = 0;
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INITIALIZE_PASS_BEGIN(MipsPreLegalizerCombiner, DEBUG_TYPE,
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"Combine Mips machine instrs before legalization", false,
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false)
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INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
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INITIALIZE_PASS_END(MipsPreLegalizerCombiner, DEBUG_TYPE,
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"Combine Mips machine instrs before legalization", false,
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false)
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namespace llvm {
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FunctionPass *createMipsPreLegalizeCombiner() {
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return new MipsPreLegalizerCombiner();
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}
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} // end namespace llvm
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