[GlobalISel] Make LegalizerInfo accessible in LegalizerHelper

Summary:
We don’t actually use LegalizerInfo in Legalizer pass, it’s just passed
as an argument.

In order to check if an instruction is legal or not, we need to get LegalizerInfo
by calling `MI.getParent()->getParent()->getSubtarget().getLegalizerInfo()`.
Instead, make LegalizerInfo accessible in LegalizerHelper.

Reviewers: qcolombet, aditya_nandakumar, dsanders, ab, t.p.northover, kristof.beyls

Reviewed By: qcolombet

Subscribers: dberris, llvm-commits, rovka

Differential Revision: https://reviews.llvm.org/D30838

llvm-svn: 297491

llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h

@@ -55,11 +55,9 @@ class LegalizerHelper {
   ///
   /// Considered as an opaque blob, the legal code will use and define the same
   /// registers as \p MI.
-  LegalizeResult legalizeInstrStep(MachineInstr &MI,
-                                   const LegalizerInfo &LegalizerInfo);
+  LegalizeResult legalizeInstrStep(MachineInstr &MI);
 
-  LegalizeResult legalizeInstr(MachineInstr &MI,
-                               const LegalizerInfo &LegalizerInfo);
+  LegalizeResult legalizeInstr(MachineInstr &MI);
 
   /// Legalize an instruction by emiting a runtime library call instead.
   LegalizeResult libcall(MachineInstr &MI);
@@ -97,6 +95,7 @@ class LegalizerHelper {
 
   MachineIRBuilder MIRBuilder;
   MachineRegisterInfo &MRI;
+  const LegalizerInfo &LI;
 };
 
 } // End namespace llvm.

llvm/lib/CodeGen/GlobalISel/Legalizer.cpp

@@ -151,7 +151,6 @@ bool Legalizer::runOnMachineFunction(MachineFunction &MF) {
   DEBUG(dbgs() << "Legalize Machine IR for: " << MF.getName() << '\n');
   init(MF);
   const TargetPassConfig &TPC = getAnalysis<TargetPassConfig>();
-  const LegalizerInfo &LegalizerInfo = *MF.getSubtarget().getLegalizerInfo();
   MachineOptimizationRemarkEmitter MORE(MF, /*MBFI=*/nullptr);
   LegalizerHelper Helper(MF);
 
@@ -173,7 +172,7 @@ bool Legalizer::runOnMachineFunction(MachineFunction &MF) {
       if (!isPreISelGenericOpcode(MI->getOpcode()))
         continue;
 
-      auto Res = Helper.legalizeInstr(*MI, LegalizerInfo);
+      auto Res = Helper.legalizeInstr(*MI);
 
       // Error out if we couldn't legalize this instruction. We may want to fall
       // back to DAG ISel instead in the future.

llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp

@@ -29,14 +29,13 @@
 using namespace llvm;
 
 LegalizerHelper::LegalizerHelper(MachineFunction &MF)
-  : MRI(MF.getRegInfo()) {
+    : MRI(MF.getRegInfo()), LI(*MF.getSubtarget().getLegalizerInfo()) {
   MIRBuilder.setMF(MF);
 }
 
 LegalizerHelper::LegalizeResult
-LegalizerHelper::legalizeInstrStep(MachineInstr &MI,
-                                   const LegalizerInfo &LegalizerInfo) {
-  auto Action = LegalizerInfo.getAction(MI, MRI);
+LegalizerHelper::legalizeInstrStep(MachineInstr &MI) {
+  auto Action = LI.getAction(MI, MRI);
   switch (std::get<0>(Action)) {
   case LegalizerInfo::Legal:
     return AlreadyLegal;
@@ -51,16 +50,15 @@ LegalizerHelper::legalizeInstrStep(MachineInstr &MI,
   case LegalizerInfo::FewerElements:
     return fewerElementsVector(MI, std::get<1>(Action), std::get<2>(Action));
   case LegalizerInfo::Custom:
-    return LegalizerInfo.legalizeCustom(MI, MRI, MIRBuilder) ? Legalized
-                                                             : UnableToLegalize;
+    return LI.legalizeCustom(MI, MRI, MIRBuilder) ? Legalized
+                                                  : UnableToLegalize;
   default:
     return UnableToLegalize;
   }
 }
 
 LegalizerHelper::LegalizeResult
-LegalizerHelper::legalizeInstr(MachineInstr &MI,
-                               const LegalizerInfo &LegalizerInfo) {
+LegalizerHelper::legalizeInstr(MachineInstr &MI) {
   SmallVector<MachineInstr *, 4> WorkList;
   MIRBuilder.recordInsertions(
       [&](MachineInstr *MI) { WorkList.push_back(MI); });
@@ -70,7 +68,7 @@ LegalizerHelper::legalizeInstr(MachineInstr &MI,
   LegalizeResult Res;
   unsigned Idx = 0;
   do {
-    Res = legalizeInstrStep(*WorkList[Idx], LegalizerInfo);
+    Res = legalizeInstrStep(*WorkList[Idx]);
     if (Res == UnableToLegalize) {
       MIRBuilder.stopRecordingInsertions();
       return UnableToLegalize;