[llvm] [InferAddressSpaces] Infer pointer stored and then loaded from global variable (PR #159755)

[Wenju He via llvm-commits]

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@@ -373,6 +399,19 @@ getPointerOperands(const Value &V, const DataLayout &DL,
     auto *P2I = cast<Operator>(Op.getOperand(0));
     return {P2I->getOperand(0)};
   }
+  case Instruction::Load: {
+    assert(V.getType()->isPtrOrPtrVectorTy());
+    if (const auto *GV = cast<GlobalVariable>(Op.getOperand(0))) {
+      assert(isLocallyAccessedBySimpleLoadsStores(
+          GV, cast<LoadInst>(&V)->getFunction()));
+      SmallVector<Value *, 2> PtrOps;
+      for (const auto *U : GV->users())
+        if (isa<StoreInst>(U))
+          PtrOps.push_back(cast<Operator>(U)->getOperand(0));
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wenju-he wrote:

> Nitpick: you could use a `dyn_cast` to avoid the `isa + cast<>`. It also makes obvious which operand we're getting (I had to check if 0 was the value or the pointer).

done. I wasn't using this because this requires a const_cast

https://github.com/llvm/llvm-project/pull/159755