1 files changed, 14 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 16196b0..ddbba80 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -3559,10 +3559,15 @@ private:
   /// Original Address.
   Value *Original;
 
+  /// Common value among addresses
+  Value *CommonValue = nullptr;
+
 public:
   AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue)
       : SQ(_SQ), Original(OriginalValue) {}
 
+  ~AddressingModeCombiner() { eraseCommonValueIfDead(); }
+
   /// Get the combined AddrMode
   const ExtAddrMode &getAddrMode() const { return AddrModes[0]; }
 
@@ -3647,13 +3652,21 @@ public:
     if (!initializeMap(Map))
       return false;
 
-    Value *CommonValue = findCommon(Map);
+    CommonValue = findCommon(Map);
     if (CommonValue)
       AddrModes[0].SetCombinedField(DifferentField, CommonValue, AddrModes);
     return CommonValue != nullptr;
   }
 
 private:
+  /// `CommonValue` may be a placeholder inserted by us.
+  /// If the placeholder is not used, we should remove this dead instruction.
+  void eraseCommonValueIfDead() {
+    if (CommonValue && CommonValue->getNumUses() == 0)
+      if (Instruction *CommonInst = dyn_cast<Instruction>(CommonValue))
+        CommonInst->eraseFromParent();
+  }
+
   /// Initialize Map with anchor values. For address seen
   /// we set the value of different field saw in this address.
   /// At the same time we find a common type for different field we will