[clang] [clang] Make -fveclib={ArmPL, SLEEF} imply -fno-math-errno (PR #112580)

[Paul Walker via cfe-commits]

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@@ -502,6 +502,10 @@ def err_sls_hardening_arm_not_supported : Error<
 def warn_drv_large_data_threshold_invalid_code_model: Warning<
   "'%0' only applies to medium and large code models">,
   InGroup<UnusedCommandLineArgument>;
+def warn_drv_math_errno_reenabled_after_veclib: Warning<
+  "math errno re-enabled by '%0' after it was implicitly disabled by '%1',"
+  " this may prevent vectorization with the specified vector library">,
+  InGroup<MathErrnoEnabledWithVecLib>;
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paulwalker-arm wrote:

I'd rather not link the warning to any specific optimisation.  I'd prefer something simpler like "..., this may limit the utilisation of the vector library.".

https://github.com/llvm/llvm-project/pull/112580