[clang] [CIR] Cleanup support for C functions (PR #136854)

[Andy Kaylor via cfe-commits]

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@@ -247,8 +248,21 @@ void CIRGenModule::emitGlobalFunctionDefinition(clang::GlobalDecl gd,
              "function definition with a non-identifier for a name");
     return;
   }
-  cir::FuncType funcType =
-      cast<cir::FuncType>(convertType(funcDecl->getType()));
+
+  cir::FuncType funcType;
+  // TODO: Move this to arrangeFunctionDeclaration when it is
+  // implemented.
+  // When declaring a function without a prototype, always use a
+  // non-variadic type.
+  if (CanQual<FunctionNoProtoType> noProto =
+          funcDecl->getType()
+              ->getCanonicalTypeUnqualified()
+              .getAs<FunctionNoProtoType>()) {
+    const CIRGenFunctionInfo &fi = getTypes().arrangeCIRFunctionInfo(
+        noProto->getReturnType(), {}, RequiredArgs::All);
+    funcType = getTypes().getFunctionType(fi);
+  } else
----------------
andykaylor wrote:

LLVM Coding Standards require braces for the `else` if they are required for the `if`.

https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements

https://github.com/llvm/llvm-project/pull/136854