[llvm] [clang-tools-extra] [clang] [CLANG] Add warning when INF or NAN are used in a binary operation or as function argument in fast math mode. (PR #76873)

[Aaron Ballman via cfe-commits]

================
@@ -2835,6 +2835,9 @@ class Preprocessor {
     if (Identifier.getIdentifierInfo()->isRestrictExpansion() &&
         !SourceMgr.isInMainFile(Identifier.getLocation()))
       emitRestrictExpansionWarning(Identifier);
+
+    if (Identifier.getIdentifierInfo()->getName() == "INFINITY")
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AaronBallman wrote:

Because there are other C standard libraries which do something different. For example, musl: https://git.musl-libc.org/cgit/musl/tree/include/math.h#n18

https://github.com/llvm/llvm-project/pull/76873