[clang] [clang] Set correct FPOptions if attribute 'optnone' presents (PR #85605)

[John McCall via cfe-commits]

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@@ -1495,6 +1495,10 @@ Decl *Parser::ParseFunctionDefinition(ParsingDeclarator &D,
     return Actions.ActOnFinishFunctionBody(Res, nullptr, false);
   }
 
+  // Some function attributes (like OptimizeNoneAttr) affect FP options.
+  Sema::FPFeaturesStateRAII SaveFPFeatures(Actions);
+  Actions.applyFunctionAttributesBeforeParsingBody(Res);
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rjmccall wrote:

Hmm.  There are actually a lot of paths that call into `ParseFunctionStatementBody` like this.  Rather than changing all of them, can we just do this in `ActOnStartOfFunctionDef` / `ActOnFinishFunctionBody`?  We do a lot of similar context push/pop operations there already.

Please test an inline C++ method (which are delayed and use a different path) and ObjC method parsing (which also use a different path).

https://github.com/llvm/llvm-project/pull/85605