[llvm] [DirectX] Resources and simple GEP traversal in DXILMemIntrinsics (PR #173054)

[Damyan Pepper via llvm-commits]

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@@ -60,6 +62,53 @@ void expandMemSet(MemSetInst *MemSet) {
   MemSet->eraseFromParent();
 }
 
+static Type *getPointeeType(Value *Ptr, const DataLayout &DL) {
+  if (auto *GV = dyn_cast<GlobalVariable>(Ptr))
+    return GV->getValueType();
+  if (auto *AI = dyn_cast<AllocaInst>(Ptr))
+    return AI->getAllocatedType();
+
+  if (auto *II = dyn_cast<IntrinsicInst>(Ptr)) {
+    if (II->getIntrinsicID() == Intrinsic::dx_resource_getpointer) {
+      Type *Ty = cast<dxil::AnyResourceExtType>(II->getArgOperand(0)->getType())
+                     ->getResourceType();
+      assert(Ty && "getpointer used on untyped resource");
+      return Ty;
+    }
+  }
+
+  if (auto *GEP = dyn_cast<GEPOperator>(Ptr)) {
+    Type *Ty = GEP->getResultElementType();
+    if (!Ty->isIntegerTy(8))
+      return Ty;
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damyanp wrote:

Is it obvious why 8-bit ints are different?

https://github.com/llvm/llvm-project/pull/173054