[llvm] [GlobalISel] Avoid repeated target info queries in combiners (PR #196530)

[Cullen Rhodes via llvm-commits]

https://github.com/c-rhodes created https://github.com/llvm/llvm-project/pull/196530

tryCombineAllImpl queries target info for every instruction. Cache
TargetInstrInfo/TargetRegisterInfo/RegisterBankInfo in CombinerHelper and pass
to executeMatchTable instead.

This avoids repeated virtual calls on the combiner executeMatchTable path.

CTMark -0.08% geomean improvement on aarch64-O0-g.

https://llvm-compile-time-tracker.com/compare.php?from=71fef6d5a306d1adf8bf7d30d2fe9e286380fecf&to=13bc49510657450402c066098e3a4b7d1af9d0e6&stat=instructions%3Au

Assisted-by: codex

>From 13bc49510657450402c066098e3a4b7d1af9d0e6 Mon Sep 17 00:00:00 2001
From: Cullen Rhodes <cullen.rhodes at arm.com>
Date: Fri, 8 May 2026 12:17:40 +0000
Subject: [PATCH] [GlobalISel] Avoid repeated target info queries in combiners

---
 llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h     | 8 ++++++++
 llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp            | 1 +
 .../TableGen/GlobalISelCombinerEmitter/match-table.td     | 3 +--
 llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp         | 5 ++---
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h b/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
index 97f29015c6911..6fa435270334a 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
@@ -44,6 +44,7 @@ class LegalizerInfo;
 struct LegalityQuery;
 class RegisterBank;
 class RegisterBankInfo;
+class TargetInstrInfo;
 class TargetLowering;
 class TargetRegisterInfo;
 
@@ -120,6 +121,7 @@ class CombinerHelper {
   MachineDominatorTree *MDT;
   bool IsPreLegalize;
   const LegalizerInfo *LI;
+  const TargetInstrInfo *TII;
   const RegisterBankInfo *RBI;
   const TargetRegisterInfo *TRI;
 
@@ -135,6 +137,12 @@ class CombinerHelper {
     return Builder;
   }
 
+  const TargetInstrInfo &getTII() const { return *TII; }
+
+  const TargetRegisterInfo &getTRI() const { return *TRI; }
+
+  const RegisterBankInfo &getRBI() const { return *RBI; }
+
   const TargetLowering &getTargetLowering() const;
 
   const MachineFunction &getMachineFunction() const;
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index c58fb84a3890e..8f2ef1d5efa94 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -62,6 +62,7 @@ CombinerHelper::CombinerHelper(GISelChangeObserver &Observer,
                                const LegalizerInfo *LI)
     : Builder(B), MRI(Builder.getMF().getRegInfo()), Observer(Observer), VT(VT),
       MDT(MDT), IsPreLegalize(IsPreLegalize), LI(LI),
+      TII(Builder.getMF().getSubtarget().getInstrInfo()),
       RBI(Builder.getMF().getSubtarget().getRegBankInfo()),
       TRI(Builder.getMF().getSubtarget().getRegisterInfo()) {
   (void)this->VT;
diff --git a/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table.td b/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table.td
index 8907cfe811abd..daeb17a61959c 100644
--- a/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table.td
+++ b/llvm/test/TableGen/GlobalISelCombinerEmitter/match-table.td
@@ -84,12 +84,11 @@ def MyCombiner: GICombiner<"GenMyCombiner", [
 
 // Verify we reset MatchData on each tryCombineAll
 // CHECK:      bool GenMyCombiner::tryCombineAll(MachineInstr &I) const {
-// CHECK-NEXT:   const TargetSubtargetInfo &ST = MF.getSubtarget();
 // CHECK-NEXT:   const PredicateBitset AvailableFeatures = getAvailableFeatures();
 // CHECK-NEXT:   B.setInstrAndDebugLoc(I);
 // CHECK-NEXT:   State.MIs.clear();
 // CHECK-NEXT:   State.MIs.push_back(&I);
-// CHECK-NEXT:   if (executeMatchTable(*this, State, ExecInfo, B, getMatchTable(), *ST.getInstrInfo(), MRI, *MRI.getTargetRegisterInfo(), *ST.getRegBankInfo(), AvailableFeatures, /*CoverageInfo*/ nullptr))
+// CHECK-NEXT:   if (executeMatchTable(*this, State, ExecInfo, B, getMatchTable(), Helper.getTII(), MRI, Helper.getTRI(), Helper.getRBI(), AvailableFeatures, /*CoverageInfo*/ nullptr))
 // CHECK-NEXT:     return true;
 // CHECK-NEXT:   }
 // CHECK-EMPTY:
diff --git a/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp b/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp
index 56b39fcd1cc9e..5f13fb6303a35 100644
--- a/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelCombinerEmitter.cpp
@@ -2560,15 +2560,14 @@ void GICombinerEmitter::emitRuleConfigImpl(raw_ostream &OS) {
 void GICombinerEmitter::emitAdditionalImpl(raw_ostream &OS) {
   OS << "bool " << getClassName() << "::" << getCombineAllMethodName()
      << "(MachineInstr &I) const {\n"
-     << "  const TargetSubtargetInfo &ST = MF.getSubtarget();\n"
      << "  const PredicateBitset AvailableFeatures = "
         "getAvailableFeatures();\n"
      << "  B.setInstrAndDebugLoc(I);\n"
      << "  State.MIs.clear();\n"
      << "  State.MIs.push_back(&I);\n"
      << "  if (executeMatchTable(*this, State, ExecInfo, B"
-     << ", getMatchTable(), *ST.getInstrInfo(), MRI, "
-        "*MRI.getTargetRegisterInfo(), *ST.getRegBankInfo(), AvailableFeatures"
+     << ", getMatchTable(), Helper.getTII(), MRI, Helper.getTRI(), "
+        "Helper.getRBI(), AvailableFeatures"
      << ", /*CoverageInfo*/ nullptr)) {\n"
      << "    return true;\n"
      << "  }\n\n"