[llvm-branch-commits] [llvm] [SelectionDAGBuilder] Use address width when lowering ptrtoaddr (PR #139423)

[Matt Arsenault via llvm-branch-commits]

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@@ -3878,7 +3878,18 @@ void SelectionDAGBuilder::visitSIToFP(const User &I) {
 }
 
 void SelectionDAGBuilder::visitPtrToAddr(const User &I) {
-  visitPtrToInt(I);
+  const auto &TLI = DAG.getTargetLoweringInfo();
+  const DataLayout &DL = DAG.getDataLayout();
+  LLVMContext &Ctx = *DAG.getContext();
+  // ptrtoaddr is equivalent to a truncate of ptrtoint to address/index width
+  SDValue N = getValue(I.getOperand(0));
+  Type *PtrTy = I.getOperand(0)->getType();
+  EVT AddrVT = EVT::getIntegerVT(Ctx, DL.getPointerAddressSizeInBits(PtrTy));
+  if (auto *VTy = dyn_cast<VectorType>(PtrTy))
+    AddrVT = EVT::getVectorVT(Ctx, AddrVT, VTy->getElementCount());
+  N = DAG.getPtrExtOrTrunc(N, getCurSDLoc(), AddrVT);
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arsenm wrote:

The LangRef says that it's always zero extend, but DAG.getPtrExtOrTrunc's comment suggests it may decide to be another extension some day? 

https://github.com/llvm/llvm-project/pull/139423