[PATCH] D84906: [NFC] Use GetUnderlyingObjects in findAllocaForValue

[Vitaly Buka via Phabricator via llvm-commits]

vitalybuka created this revision.
vitalybuka added reviewers: eugenis, glider.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a project: LLVM.
vitalybuka requested review of this revision.

Depends on D84621 <https://reviews.llvm.org/D84621>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D84906

Files:
  llvm/lib/Analysis/ValueTracking.cpp


Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -4299,47 +4299,12 @@
   return true;
 }
 
-static AllocaInst *
-findAllocaForValue(Value *V, DenseMap<Value *, AllocaInst *> &AllocaForValue) {
-  if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
-    return AI;
-  // See if we've already calculated (or started to calculate) alloca for a
-  // given value.
-  auto I = AllocaForValue.find(V);
-  if (I != AllocaForValue.end())
-    return I->second;
-  // Store 0 while we're calculating alloca for value V to avoid
-  // infinite recursion if the value references itself.
-  AllocaForValue[V] = nullptr;
-  AllocaInst *Res = nullptr;
-  if (CastInst *CI = dyn_cast<CastInst>(V))
-    Res = findAllocaForValue(CI->getOperand(0), AllocaForValue);
-  else if (PHINode *PN = dyn_cast<PHINode>(V)) {
-    for (Value *IncValue : PN->incoming_values()) {
-      // Allow self-referencing phi-nodes.
-      if (IncValue == PN)
-        continue;
-      AllocaInst *IncValueAI = findAllocaForValue(IncValue, AllocaForValue);
-      // AI for incoming values should exist and should all be equal.
-      if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
-        return nullptr;
-      Res = IncValueAI;
-    }
-  } else if (GetElementPtrInst *EP = dyn_cast<GetElementPtrInst>(V)) {
-    Res = findAllocaForValue(EP->getPointerOperand(), AllocaForValue);
-  } else {
-#ifndef NDEBUG
-    dbgs() << "Alloca search cancelled on unknown instruction: " << *V << "\n";
-#endif
-  }
-  if (Res)
-    AllocaForValue[V] = Res;
-  return Res;
-}
-
 AllocaInst *llvm::findAllocaForValue(Value *V) {
-  DenseMap<Value *, AllocaInst *> AllocaForValue;
-  return ::findAllocaForValue(V, AllocaForValue);
+  SmallVector<const Value *, 16> Objects;
+  GetUnderlyingObjects(V, Objects);
+  if (Objects.size() != 1)
+    return nullptr;
+  return const_cast<AllocaInst *>(dyn_cast<AllocaInst>(Objects.front()));
 }
 
 static bool onlyUsedByLifetimeMarkersOrDroppableInstsHelper(


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