[llvm] [DirectX] Disallow ElementIndex for raw buffer accesses (PR #173320)

[Justin Bogner via llvm-commits]

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@@ -272,6 +272,22 @@ class OpLowerer {
     return false;
   }
 
+  Error validateRawBufferElementIndex(Value *Resource, Value *ElementIndex) {
+    bool IsStructured =
+        cast<RawBufferExtType>(Resource->getType())->isStructured();
+    bool IsPoison = isa<PoisonValue>(ElementIndex);
+
+    if (IsStructured && IsPoison)
+      return make_error<StringError>(
+          "Element index of structured buffer may not be poison",
+          inconvertibleErrorCode());
+    else if (!IsStructured && !IsPoison)
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bogner wrote:

Personally I like the else here since the condition parallels the previous one, but I don't feel strongly so I've updated it to make clang-tidy (and I suppose it seems you as well) happy here.

https://github.com/llvm/llvm-project/pull/173320