[llvm] Add the 'initializes' attribute langref and support (PR #84803)

[Nikita Popov via llvm-commits]

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@@ -2059,6 +2060,27 @@ void Verifier::verifyParameterAttrs(AttributeSet Attrs, Type *Ty,
     }
   }
 
+  if (Attrs.hasAttribute(Attribute::Initializes)) {
+    auto Inits = Attrs.getAttribute(Attribute::Initializes).getInitializes();
+    Check(!Inits.empty(), "Attribute 'initializes' does not support empty list",
+          V);
+
+    Check(Inits[0].getLower().slt(Inits[0].getUpper()),
+          "Attribute 'initializes' requires interval lower less than upper", V);
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nikic wrote:

Reuse isOrderedRanges here?

https://github.com/llvm/llvm-project/pull/84803