[llvm] 353729b - [AMDGPU] Avoid quadratic erase in SIInstrWorklist (#211801)

[via llvm-commits]

Author: Arseniy Obolenskiy
Date: 2026-07-25T22:31:57+02:00
New Revision: 353729bbe4c53086c9acf3a9d1a4a88a61eec997

URL: https://github.com/llvm/llvm-project/commit/353729bbe4c53086c9acf3a9d1a4a88a61eec997
DIFF: https://github.com/llvm/llvm-project/commit/353729bbe4c53086c9acf3a9d1a4a88a61eec997.diff

LOG: [AMDGPU] Avoid quadratic erase in SIInstrWorklist (#211801)

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
    llvm/lib/Target/AMDGPU/SIInstrInfo.h

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 28914d598a72d..633a815447d9a 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -7852,7 +7852,8 @@ SIInstrInfo::legalizeOperands(MachineInstr &MI,
 }
 
 void SIInstrWorklist::insert(MachineInstr *MI) {
-  InstrList.insert(MI);
+  if (InSet.insert(MI).second)
+    InstrList.push_back(MI);
   // Add MBUF instructiosn to deferred list.
   int RsrcIdx =
       AMDGPU::getNamedOperandIdx(MI->getOpcode(), AMDGPU::OpName::srsrc);

diff  --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.h b/llvm/lib/Target/AMDGPU/SIInstrInfo.h
index 8e15b7b45b609..1954e9c2f0d21 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.h
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.h
@@ -19,6 +19,7 @@
 #include "SIRegisterInfo.h"
 #include "Utils/AMDGPUBaseInfo.h"
 #include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 #include "llvm/CodeGen/TargetSchedule.h"
 
@@ -70,20 +71,19 @@ struct SIInstrWorklist {
 
   void insert(MachineInstr *MI);
 
-  MachineInstr *top() const {
-    const auto *iter = InstrList.begin();
-    return *iter;
-  }
+  MachineInstr *top() const { return InstrList[Front]; }
 
   void erase_top() {
-    const auto *iter = InstrList.begin();
-    InstrList.erase(iter);
+    InSet.erase(InstrList[Front]);
+    ++Front;
   }
 
-  bool empty() const { return InstrList.empty(); }
+  bool empty() const { return Front == InstrList.size(); }
 
   void clear() {
     InstrList.clear();
+    Front = 0;
+    InSet.clear();
     DeferredList.clear();
   }
 
@@ -93,7 +93,9 @@ struct SIInstrWorklist {
 
 private:
   /// InstrList contains the MachineInstrs.
-  SetVector<MachineInstr *> InstrList;
+  SmallVector<MachineInstr *> InstrList;
+  SmallPtrSet<MachineInstr *, 8> InSet;
+  unsigned Front = 0;
   /// Deferred instructions are specific MachineInstr
   /// that will be added by insert method.
   SetVector<MachineInstr *> DeferredList;