[clang] [X86] Relax AVX ABI warning on internal functions (PR #157570)

[John McCall via cfe-commits]

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@@ -1513,12 +1513,17 @@ static void initFeatureMaps(const ASTContext &Ctx,
 
 static bool checkAVXParamFeature(DiagnosticsEngine &Diag,
                                  SourceLocation CallLoc,
+                                 const FunctionDecl &Callee,
                                  const llvm::StringMap<bool> &CallerMap,
                                  const llvm::StringMap<bool> &CalleeMap,
                                  QualType Ty, StringRef Feature,
                                  bool IsArgument) {
   bool CallerHasFeat = CallerMap.lookup(Feature);
   bool CalleeHasFeat = CalleeMap.lookup(Feature);
+  // No explicit features and the function is internal, be permissive.
+  if (!CallerHasFeat && !CalleeHasFeat && !Callee.isExternallyVisible())
+    return false;
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rjmccall wrote:

Can you explain why explicit features turn the warning back on?

Also, this seems like a generally-useful thing. Do we have similar warnings for other targets?

https://github.com/llvm/llvm-project/pull/157570