[clang] [CIR] Function type return type improvements (PR #128787)

[Erich Keane via cfe-commits]

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@@ -424,6 +424,10 @@ LogicalResult cir::FuncOp::verifyType() {
   if (!isa<cir::FuncType>(type))
     return emitOpError("requires '" + getFunctionTypeAttrName().str() +
                        "' attribute of function type");
+  if (auto rt = type.getReturnTypes();
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erichkeane wrote:

Is there anywhere that we check that `rt.size() == 1` as a part of the verifier?

https://github.com/llvm/llvm-project/pull/128787