[clang] [clang] Add deprecation warning for `-Ofast` driver option (PR #98736)

[Vlad Serebrennikov via cfe-commits]

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@@ -931,7 +931,8 @@ def O : Joined<["-"], "O">, Group<O_Group>,
 def O_flag : Flag<["-"], "O">, Visibility<[ClangOption, CC1Option, FC1Option]>,
   Alias<O>, AliasArgs<["1"]>;
 def Ofast : Joined<["-"], "Ofast">, Group<O_Group>,
-  Visibility<[ClangOption, CC1Option, FlangOption]>;
+  Visibility<[ClangOption, CC1Option, FlangOption]>,
+  HelpText<"Deprecated; use -O3, possibly with -ffast-math">;
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Endilll wrote:

(But I made sure to put arguments in quotes)

https://github.com/llvm/llvm-project/pull/98736