[PATCH] D67839: [FPEnv] Document requirement of function attributes with constrained floating point

[Ulrich Weigand via Phabricator via llvm-commits]

uweigand added a comment.

I agree with marking function call sites as "strictfp".

But I'm wondering how you came up with this particular list for function definitions?   In particular, I'm not sure whether noimplicitfloat is really needed.  I understand this flag is supposed to prevent unintended use of floating-point registers (e.g. for Linux kernel code).  You don't really need to prevent that for constrained floating point semantics, I think.  (You do need to prevent introduction of floating-point instruction that might cause spurious exception, but e.g. introducing moves through FP registers should still be fine.)

As to "strictfp" at the function definition, does this actually do anything currently?  I cannot find any LLVM code that checks for this. The documentation also doesn't really say.


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