kpn added a comment.

What's the plan for tying this to strictfp? Because I don't it should be tied 
to cases where we use the constrained intrinsics but the exceptions are ignored 
and the default rounding is in stated. Those instructions are supposed to 
behave the same as the non-constrained instructions. So keying off the presence 
of the strictfp attribute on the function definition, or the (equivalent) 
presence of constrained intrinsics, would be too simple.

I don't see an obvious connection between denormals and exception behavior, and 
the rounding mode has the same problem. It would be surprising if changing the 
rounding mode changed denormal handling or optimization even when the new 
rounding mode would have identical results. It would also be surprising if 
changing the rounding mode back to the default round-to-nearest changed how 
denormals are handled.

Would we get different denormal behavior with a clang flag vs using a #pragma 
at the top of a source file? That seems surprising as well.

In the abstract I can see lumping in denormal handing with the rest of the FP 
environment handling. But in the LLVM context I don't see how we can tie use of 
the constrained intrinsics to denormals.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D142907/new/

https://reviews.llvm.org/D142907

_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits

Reply via email to