[llvm] TargetLibraryInfo: Disable roundeven variants by default except for GLIBC (PR #188898)

[Matt Arsenault via llvm-commits]

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@@ -674,6 +680,12 @@ static void initializeLibCalls(TargetLibraryInfoImpl &TLI, const Triple &T,
     TLI.setUnavailable(LibFunc_sqrtl_finite);
   }
 
+  if (T.isOSLinux() && T.isGNUEnvironment()) {
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arsenm wrote:

At minmum this should comment the version it's available in 

https://github.com/llvm/llvm-project/pull/188898