[libc] [llvm] [libc] add flag for FP_*LOGB0/NAN values (PR #86723)

[via llvm-commits]

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@@ -30,11 +30,21 @@
 #define INFINITY __builtin_inf()
 #define NAN __builtin_nanf("")
 
+#ifdef __FP_LOGB0_MIN
 #define FP_ILOGB0 (-INT_MAX - 1)
-#define FP_ILOGBNAN INT_MAX
-
 #define FP_LLOGB0 (-LONG_MAX - 1)
+#else
+#define FP_ILOGB0 (-INT_MAX)
+#define FP_LLOGB0 (-LONG_MAX)
+#endif
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lntue wrote:

We should just keep `FP_ILOGB0` and `FP_LLOGB0` as before.

https://github.com/llvm/llvm-project/pull/86723