[RISCV][GISel] Add initial pre-legalizer combiners copying from AArch64.

llvm/lib/Target/RISCV/CMakeLists.txt

@@ -17,6 +17,10 @@ tablegen(LLVM RISCVGenSubtargetInfo.inc -gen-subtarget)
 
 set(LLVM_TARGET_DEFINITIONS RISCVGISel.td)
 tablegen(LLVM RISCVGenGlobalISel.inc -gen-global-isel)
+tablegen(LLVM RISCVGenO0PreLegalizeGICombiner.inc -gen-global-isel-combiner
+              -combiners="RISCVO0PreLegalizerCombiner")
+tablegen(LLVM RISCVGenPreLegalizeGICombiner.inc -gen-global-isel-combiner
+              -combiners="RISCVPreLegalizerCombiner")
 
 add_public_tablegen_target(RISCVCommonTableGen)
 
@@ -49,6 +53,8 @@ add_llvm_target(RISCVCodeGen
   GISel/RISCVCallLowering.cpp
   GISel/RISCVInstructionSelector.cpp
   GISel/RISCVLegalizerInfo.cpp
+  GISel/RISCVO0PreLegalizerCombiner.cpp
+  GISel/RISCVPreLegalizerCombiner.cpp
   GISel/RISCVRegisterBankInfo.cpp
 
   LINK_COMPONENTS

llvm/lib/Target/RISCV/GISel/RISCVO0PreLegalizerCombiner.cpp

@@ -0,0 +1,155 @@
+//=== RISCVO0PreLegalizerCombiner.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
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass does combining of machine instructions at the generic MI level,
+// before the legalizer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVSubtarget.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/GISelKnownBits.h"
+#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.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"
+
+#define GET_GICOMBINER_DEPS
+#include "RISCVGenO0PreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_DEPS
+
+#define DEBUG_TYPE "riscv-O0-prelegalizer-combiner"
+
+using namespace llvm;
+
+namespace {
+#define GET_GICOMBINER_TYPES
+#include "RISCVGenO0PreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_TYPES
+
+class RISCVO0PreLegalizerCombinerImpl : public Combiner {
+protected:
+  // TODO: Make CombinerHelper methods const.
+  mutable CombinerHelper Helper;
+  const RISCVO0PreLegalizerCombinerImplRuleConfig &RuleConfig;
+  const RISCVSubtarget &STI;
+
+public:
+  RISCVO0PreLegalizerCombinerImpl(
+      MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
+      GISelKnownBits &KB, GISelCSEInfo *CSEInfo,
+      const RISCVO0PreLegalizerCombinerImplRuleConfig &RuleConfig,
+      const RISCVSubtarget &STI);
+
+  static const char *getName() { return "RISCVO0PreLegalizerCombiner"; }
+
+  bool tryCombineAll(MachineInstr &I) const override;
+
+private:
+#define GET_GICOMBINER_CLASS_MEMBERS
+#include "RISCVGenO0PreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_CLASS_MEMBERS
+};
+
+#define GET_GICOMBINER_IMPL
+#include "RISCVGenO0PreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_IMPL
+
+RISCVO0PreLegalizerCombinerImpl::RISCVO0PreLegalizerCombinerImpl(
+    MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
+    GISelKnownBits &KB, GISelCSEInfo *CSEInfo,
+    const RISCVO0PreLegalizerCombinerImplRuleConfig &RuleConfig,
+    const RISCVSubtarget &STI)
+    : Combiner(MF, CInfo, TPC, &KB, CSEInfo),
+      Helper(Observer, B, /*IsPreLegalize*/ true, &KB), RuleConfig(RuleConfig),
+      STI(STI),
+#define GET_GICOMBINER_CONSTRUCTOR_INITS
+#include "RISCVGenO0PreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_CONSTRUCTOR_INITS
+{
+}
+
+// Pass boilerplate
+// ================
+
+class RISCVO0PreLegalizerCombiner : public MachineFunctionPass {
+public:
+  static char ID;
+
+  RISCVO0PreLegalizerCombiner();
+
+  StringRef getPassName() const override {
+    return "RISCVO0PreLegalizerCombiner";
+  }
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+private:
+  RISCVO0PreLegalizerCombinerImplRuleConfig RuleConfig;
+};
+} // end anonymous namespace
+
+void RISCVO0PreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<TargetPassConfig>();
+  AU.setPreservesCFG();
+  getSelectionDAGFallbackAnalysisUsage(AU);
+  AU.addRequired<GISelKnownBitsAnalysis>();
+  AU.addPreserved<GISelKnownBitsAnalysis>();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+RISCVO0PreLegalizerCombiner::RISCVO0PreLegalizerCombiner()
+    : MachineFunctionPass(ID) {
+  initializeRISCVO0PreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
+
+  if (!RuleConfig.parseCommandLineOption())
+    report_fatal_error("Invalid rule identifier");
+}
+
+bool RISCVO0PreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
+  if (MF.getProperties().hasProperty(
+          MachineFunctionProperties::Property::FailedISel))
+    return false;
+  auto &TPC = getAnalysis<TargetPassConfig>();
+
+  const Function &F = MF.getFunction();
+  GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
+
+  const RISCVSubtarget &ST = MF.getSubtarget<RISCVSubtarget>();
+
+  CombinerInfo CInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
+                     /*LegalizerInfo*/ nullptr, /*EnableOpt*/ false,
+                     F.hasOptSize(), F.hasMinSize());
+  RISCVO0PreLegalizerCombinerImpl Impl(MF, CInfo, &TPC, *KB,
+                                       /*CSEInfo*/ nullptr, RuleConfig, ST);
+  return Impl.combineMachineInstrs();
+}
+
+char RISCVO0PreLegalizerCombiner::ID = 0;
+INITIALIZE_PASS_BEGIN(RISCVO0PreLegalizerCombiner, DEBUG_TYPE,
+                      "Combine RISCV machine instrs before legalization", false,
+                      false)
+INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
+INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
+INITIALIZE_PASS_DEPENDENCY(GISelCSEAnalysisWrapperPass)
+INITIALIZE_PASS_END(RISCVO0PreLegalizerCombiner, DEBUG_TYPE,
+                    "Combine RISCV machine instrs before legalization", false,
+                    false)
+
+namespace llvm {
+FunctionPass *createRISCVO0PreLegalizerCombiner() {
+  return new RISCVO0PreLegalizerCombiner();
+}
+} // end namespace llvm

llvm/lib/Target/RISCV/GISel/RISCVPreLegalizerCombiner.cpp

@@ -0,0 +1,169 @@
+//=== RISCVPreLegalizerCombiner.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
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass does combining of machine instructions at the generic MI level,
+// before the legalizer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVSubtarget.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/GISelKnownBits.h"
+#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.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"
+
+#define GET_GICOMBINER_DEPS
+#include "RISCVGenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_DEPS
+
+#define DEBUG_TYPE "riscv-prelegalizer-combiner"
+
+using namespace llvm;
+
+namespace {
+
+#define GET_GICOMBINER_TYPES
+#include "RISCVGenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_TYPES
+
+class RISCVPreLegalizerCombinerImpl : public Combiner {
+protected:
+  // TODO: Make CombinerHelper methods const.
+  mutable CombinerHelper Helper;
+  const RISCVPreLegalizerCombinerImplRuleConfig &RuleConfig;
+  const RISCVSubtarget &STI;
+
+public:
+  RISCVPreLegalizerCombinerImpl(
+      MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
+      GISelKnownBits &KB, GISelCSEInfo *CSEInfo,
+      const RISCVPreLegalizerCombinerImplRuleConfig &RuleConfig,
+      const RISCVSubtarget &STI, MachineDominatorTree *MDT,
+      const LegalizerInfo *LI);
+
+  static const char *getName() { return "RISCV00PreLegalizerCombiner"; }
+
+  bool tryCombineAll(MachineInstr &I) const override;
+
+private:
+#define GET_GICOMBINER_CLASS_MEMBERS
+#include "RISCVGenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_CLASS_MEMBERS
+};
+
+#define GET_GICOMBINER_IMPL
+#include "RISCVGenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_IMPL
+
+RISCVPreLegalizerCombinerImpl::RISCVPreLegalizerCombinerImpl(
+    MachineFunction &MF, CombinerInfo &CInfo, const TargetPassConfig *TPC,
+    GISelKnownBits &KB, GISelCSEInfo *CSEInfo,
+    const RISCVPreLegalizerCombinerImplRuleConfig &RuleConfig,
+    const RISCVSubtarget &STI, MachineDominatorTree *MDT,
+    const LegalizerInfo *LI)
+    : Combiner(MF, CInfo, TPC, &KB, CSEInfo),
+      Helper(Observer, B, /*IsPreLegalize*/ true, &KB, MDT, LI),
+      RuleConfig(RuleConfig), STI(STI),
+#define GET_GICOMBINER_CONSTRUCTOR_INITS
+#include "RISCVGenPreLegalizeGICombiner.inc"
+#undef GET_GICOMBINER_CONSTRUCTOR_INITS
+{
+}
+
+// Pass boilerplate
+// ================
+
+class RISCVPreLegalizerCombiner : public MachineFunctionPass {
+public:
+  static char ID;
+
+  RISCVPreLegalizerCombiner();
+
+  StringRef getPassName() const override { return "RISCVPreLegalizerCombiner"; }
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+private:
+  RISCVPreLegalizerCombinerImplRuleConfig RuleConfig;
+};
+} // end anonymous namespace
+
+void RISCVPreLegalizerCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<TargetPassConfig>();
+  AU.setPreservesCFG();
+  getSelectionDAGFallbackAnalysisUsage(AU);
+  AU.addRequired<GISelKnownBitsAnalysis>();
+  AU.addPreserved<GISelKnownBitsAnalysis>();
+  AU.addRequired<MachineDominatorTree>();
+  AU.addPreserved<MachineDominatorTree>();
+  AU.addRequired<GISelCSEAnalysisWrapperPass>();
+  AU.addPreserved<GISelCSEAnalysisWrapperPass>();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+RISCVPreLegalizerCombiner::RISCVPreLegalizerCombiner()
+    : MachineFunctionPass(ID) {
+  initializeRISCVPreLegalizerCombinerPass(*PassRegistry::getPassRegistry());
+
+  if (!RuleConfig.parseCommandLineOption())
+    report_fatal_error("Invalid rule identifier");
+}
+
+bool RISCVPreLegalizerCombiner::runOnMachineFunction(MachineFunction &MF) {
+  if (MF.getProperties().hasProperty(
+          MachineFunctionProperties::Property::FailedISel))
+    return false;
+  auto &TPC = getAnalysis<TargetPassConfig>();
+
+  // Enable CSE.
+  GISelCSEAnalysisWrapper &Wrapper =
+      getAnalysis<GISelCSEAnalysisWrapperPass>().getCSEWrapper();
+  auto *CSEInfo = &Wrapper.get(TPC.getCSEConfig());
+
+  const RISCVSubtarget &ST = MF.getSubtarget<RISCVSubtarget>();
+  const auto *LI = ST.getLegalizerInfo();
+
+  const Function &F = MF.getFunction();
+  bool EnableOpt =
+      MF.getTarget().getOptLevel() != CodeGenOptLevel::None && !skipFunction(F);
+  GISelKnownBits *KB = &getAnalysis<GISelKnownBitsAnalysis>().get(MF);
+  MachineDominatorTree *MDT = &getAnalysis<MachineDominatorTree>();
+  CombinerInfo CInfo(/*AllowIllegalOps*/ true, /*ShouldLegalizeIllegal*/ false,
+                     /*LegalizerInfo*/ nullptr, EnableOpt, F.hasOptSize(),
+                     F.hasMinSize());
+  RISCVPreLegalizerCombinerImpl Impl(MF, CInfo, &TPC, *KB, CSEInfo, RuleConfig,
+                                     ST, MDT, LI);
+  return Impl.combineMachineInstrs();
+}
+
+char RISCVPreLegalizerCombiner::ID = 0;
+INITIALIZE_PASS_BEGIN(RISCVPreLegalizerCombiner, DEBUG_TYPE,
+                      "Combine RISCV machine instrs before legalization", false,
+                      false)
+INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
+INITIALIZE_PASS_DEPENDENCY(GISelKnownBitsAnalysis)
+INITIALIZE_PASS_DEPENDENCY(GISelCSEAnalysisWrapperPass)
+INITIALIZE_PASS_END(RISCVPreLegalizerCombiner, DEBUG_TYPE,
+                    "Combine RISCV machine instrs before legalization", false,
+                    false)
+
+namespace llvm {
+FunctionPass *createRISCVPreLegalizerCombiner() {
+  return new RISCVPreLegalizerCombiner();
+}
+} // end namespace llvm

llvm/lib/Target/RISCV/RISCV.h

@@ -80,6 +80,12 @@ InstructionSelector *createRISCVInstructionSelector(const RISCVTargetMachine &,
                                                     RISCVSubtarget &,
                                                     RISCVRegisterBankInfo &);
 void initializeRISCVDAGToDAGISelPass(PassRegistry &);
+
+FunctionPass *createRISCVO0PreLegalizerCombiner();
+void initializeRISCVO0PreLegalizerCombinerPass(PassRegistry &);
+
+FunctionPass *createRISCVPreLegalizerCombiner();
+void initializeRISCVPreLegalizerCombinerPass(PassRegistry &);
 } // namespace llvm
 
 #endif

llvm/lib/Target/RISCV/RISCVCombine.td

@@ -0,0 +1,20 @@
+//=- RISCVCombine.td - Define RISC-V Combine Rules -----------*- tablegen -*-=//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+//
+//===----------------------------------------------------------------------===//
+
+include "llvm/Target/GlobalISel/Combine.td"
+
+def RISCVPreLegalizerCombiner: GICombiner<
+  "RISCVPreLegalizerCombinerImpl", [all_combines]> {
+}
+
+def RISCVO0PreLegalizerCombiner: GICombiner<
+  "RISCVO0PreLegalizerCombinerImpl", [optnone_combines]> {
+}

llvm/lib/Target/RISCV/RISCVGISel.td

@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 include "RISCV.td"
+include "RISCVCombine.td"
 
 def simm12Plus1 : ImmLeaf<XLenVT, [{
     return (isInt<12>(Imm) && Imm != -2048) || Imm == 2048;}]>;