[llvm] 0891575 - [InstCombine] Fix worklist management in replaceGEPIdxWithZero() fold (NFCI)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-05-23T16:21:43+02:00
New Revision: 089157518ad28b8e0fa8623b87153b4c08b341ec

URL: https://github.com/llvm/llvm-project/commit/089157518ad28b8e0fa8623b87153b4c08b341ec
DIFF: https://github.com/llvm/llvm-project/commit/089157518ad28b8e0fa8623b87153b4c08b341ec.diff

LOG: [InstCombine] Fix worklist management in replaceGEPIdxWithZero() fold (NFCI)

Make sure the old load/store operand is queued for DCE.

This should be NFC apart from worklist order effects.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index c89dbe7750f1..376b7e5052ce 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -1013,17 +1013,15 @@ static bool canReplaceGEPIdxWithZero(InstCombinerImpl &IC,
 // If we're indexing into an object with a variable index for the memory
 // access, but the object has only one element, we can assume that the index
 // will always be zero. If we replace the GEP, return it.
-template <typename T>
 static Instruction *replaceGEPIdxWithZero(InstCombinerImpl &IC, Value *Ptr,
-                                          T &MemI) {
+                                          Instruction &MemI) {
   if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Ptr)) {
     unsigned Idx;
     if (canReplaceGEPIdxWithZero(IC, GEPI, &MemI, Idx)) {
       Instruction *NewGEPI = GEPI->clone();
       NewGEPI->setOperand(Idx,
         ConstantInt::get(GEPI->getOperand(Idx)->getType(), 0));
-      NewGEPI->insertBefore(GEPI);
-      MemI.setOperand(MemI.getPointerOperandIndex(), NewGEPI);
+      IC.InsertNewInstBefore(NewGEPI, *GEPI);
       return NewGEPI;
     }
   }
@@ -1072,10 +1070,8 @@ Instruction *InstCombinerImpl::visitLoadInst(LoadInst &LI) {
     LI.setAlignment(KnownAlign);
 
   // Replace GEP indices if possible.
-  if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Op, LI)) {
-      Worklist.push(NewGEPI);
-      return &LI;
-  }
+  if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Op, LI))
+    return replaceOperand(LI, 0, NewGEPI);
 
   if (Instruction *Res = unpackLoadToAggregate(*this, LI))
     return Res;
@@ -1483,10 +1479,8 @@ Instruction *InstCombinerImpl::visitStoreInst(StoreInst &SI) {
     return eraseInstFromFunction(SI);
 
   // Replace GEP indices if possible.
-  if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Ptr, SI)) {
-      Worklist.push(NewGEPI);
-      return &SI;
-  }
+  if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Ptr, SI))
+    return replaceOperand(SI, 1, NewGEPI);
 
   // Don't hack volatile/ordered stores.
   // FIXME: Some bits are legal for ordered atomic stores; needs refactoring.