[llvm] [InstCombine][AMDGPU] Disable PtrReplacer when select has mismatch AS. (PR #98456)

[Matt Arsenault via llvm-commits]

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@@ -270,16 +270,54 @@ class PointerReplacer {
     unsigned ToAS = ASC->getDestAddressSpace();
     return (FromAS == ToAS) || IC.isValidAddrSpaceCast(FromAS, ToAS);
   }
+  bool foundASC(const Value *Op) const;
+  bool hasConflictingAS(const SelectInst *I) const;
 
   SmallPtrSet<Instruction *, 32> ValuesToRevisit;
+  SmallPtrSet<SelectInst *, 32> ValuesToRevisitAS;
   SmallSetVector<Instruction *, 4> Worklist;
   MapVector<Value *, Value *> WorkMap;
   InstCombinerImpl &IC;
   Instruction &Root;
   unsigned FromAS;
+  bool HasASC = false;
 };
 } // end anonymous namespace
 
+/// Return true iff valid addrspacecast is found on
+/// path from end of branch to root of tree.
+bool PointerReplacer::foundASC(const Value *Op) const {
+  const Instruction *TI;
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arsenm wrote:

Can you just check if the access address space matches the root address space? 

https://github.com/llvm/llvm-project/pull/98456