[llvm] [X86][GISEL] Enable Pre Legalizer Combiner (PR #172204)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,183 @@
+//===---------------- X86PreLegalizerCombiner.cpp -------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This pass does combining of machine instructions at the generic MI level,
+/// before the legalizer.
+///
+//===----------------------------------------------------------------------===//
+#include "X86.h"
+#include "X86TargetMachine.h"
+#include "llvm/CodeGen/GlobalISel/CSEInfo.h"
+#include "llvm/CodeGen/GlobalISel/Combiner.h"
+#include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
+#include "llvm/CodeGen/GlobalISel/CombinerInfo.h"
+#include "llvm/CodeGen/GlobalISel/GIMatchTableExecutorImpl.h"
+#include "llvm/CodeGen/GlobalISel/GISelValueTracking.h"
+#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
+#include "llvm/CodeGen/GlobalISel/MIPatternMatch.h"
+#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
+#include "llvm/CodeGen/GlobalISel/Utils.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/IR/Instructions.h"
+
+#define GET_GICOMBINER_DEPS
+#include "X86GenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_DEPS
+
+#define DEBUG_TYPE "x86-prelegalizer-combiner"
+
+using namespace llvm;
+using namespace MIPatternMatch;
+
+namespace {
+
+#define GET_GICOMBINER_TYPES
+#include "X86GenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_TYPES
+
+class X86PreLegalizerCombinerImpl : public Combiner {
+protected:
+  const CombinerHelper Helper;
+  const X86PreLegalizerCombinerImplRuleConfig &RuleConfig;
+  const X86Subtarget &STI;
+
+public:
+  X86PreLegalizerCombinerImpl(
+      MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
+      GISelValueTracking &VT, GISelCSEInfo *CSEInfo,
+      const X86PreLegalizerCombinerImplRuleConfig &RuleConfig,
+      const X86Subtarget &STI, MachineDominatorTree *MDT,
+      const LegalizerInfo *LI);
+
+  static const char *getName() { return "X86PreLegalizerCombiner"; }
+
+  bool tryCombineAll(MachineInstr &I) const override;
+
+  bool tryCombineAllImpl(MachineInstr &I) const;
+
+private:
+#define GET_GICOMBINER_CLASS_MEMBERS
+#include "X86GenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_CLASS_MEMBERS
+};
+
+#define GET_GICOMBINER_IMPL
+#include "X86GenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_IMPL
+
+X86PreLegalizerCombinerImpl::X86PreLegalizerCombinerImpl(
+    MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
+    GISelValueTracking &VT, GISelCSEInfo *CSEInfo,
+    const X86PreLegalizerCombinerImplRuleConfig &RuleConfig,
+    const X86Subtarget &STI, MachineDominatorTree *MDT, const LegalizerInfo *LI)
+    : Combiner(MF, CInfo, TPC, &VT, CSEInfo),
+      Helper(Observer, B, /*IsPreLegalize*/ true, &VT, MDT, LI),
+      RuleConfig(RuleConfig), STI(STI),
+#define GET_GICOMBINER_CONSTRUCTOR_INITS
+#include "X86GenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_CONSTRUCTOR_INITS
+{
+}
+
+bool X86PreLegalizerCombinerImpl::tryCombineAll(MachineInstr &MI) const {
+  if (tryCombineAllImpl(MI))
+    return true;
+  LLVM_DEBUG(dbgs() << "\nNo table match found.\nTry Custom Combine for "
+                    << MI);
+  return false;
+}
+
+class X86PreLegalizerCombiner : public MachineFunctionPass {
+public:
+  static char ID;
+
+  X86PreLegalizerCombiner();
+
+  StringRef getPassName() const override { return "X86PreLegalizerCombiner"; }
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+private:
+  X86PreLegalizerCombinerImplRuleConfig RuleConfig;
+};
+} // end anonymous namespace
+
+void X86PreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<TargetPassConfig>();
+  AU.setPreservesCFG();
+  getSelectionDAGFallbackAnalysisUsage(AU);
+  AU.addRequired<GISelValueTrackingAnalysisLegacy>();
+  AU.addPreserved<GISelValueTrackingAnalysisLegacy>();
+  AU.addRequired<MachineDominatorTreeWrapperPass>();
+  AU.addPreserved<MachineDominatorTreeWrapperPass>();
+  AU.addRequired<GISelCSEAnalysisWrapperPass>();
+  AU.addPreserved<GISelCSEAnalysisWrapperPass>();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+X86PreLegalizerCombiner::X86PreLegalizerCombiner() : MachineFunctionPass(ID) {
+  if (!RuleConfig.parseCommandLineOption())
+    report_fatal_error("Invalid rule identifier");
+}
+
+bool X86PreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
+  if (MF.getProperties().hasFailedISel())
+    return false;
+  auto &TPC = getAnalysis<TargetPassConfig>();
+
+  // Enable CSE.
+  GISelCSEAnalysisWrapper &Wrapper =
+      getAnalysis<GISelCSEAnalysisWrapperPass>().getCSEWrapper();
+  auto *CSEInfo = &Wrapper.get(TPC.getCSEConfig());
+
+  const X86Subtarget &ST = MF.getSubtarget<X86Subtarget>();
+  const auto *LI = ST.getLegalizerInfo();
+
+  const Function &F = MF.getFunction();
+  bool EnableOpt =
+      MF.getTarget().getOptLevel() != CodeGenOptLevel::None && !skipFunction(F);
+  GISelValueTracking *VT =
+      &getAnalysis<GISelValueTrackingAnalysisLegacy>().get(MF);
+  MachineDominatorTree *MDT =
+      &getAnalysis<MachineDominatorTreeWrapperPass>().getDomTree();
+  CombinerInfo CInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
+                     /*LegalizerInfo*/ nullptr, EnableOpt, F.hasOptSize(),
+                     F.hasMinSize());
+  // Disable fixed-point iteration to reduce compile-time
+  CInfo.MaxIterations = 1;
+  CInfo.ObserverLvl = CombinerInfo::ObserverLevel::SinglePass;
----------------
arsenm wrote:

These should be the defaults in CombinerInfo?

https://github.com/llvm/llvm-project/pull/172204