[PATCH] D136786: Fix `unsafe-fp-math` attribute emission.

Sat Oct 29 18:49:34 PDT 2022

michele.scandale added a comment.

In D136786#3893485 <https://reviews.llvm.org/D136786#3893485>, @andrew.w.kaylor wrote:

> My understanding is this:
>
>   unsafe-fp-math = exception_behavior(ignore) +
>                    fenv_access(off) +
>                    no_signed_zeros(on) +
>                    allow_reciprocal(on) +
>                    allow_approximate_fns(on) +
>                    allow_reassociation(on) +
>                    fp_contract(fast)
>
> The first two of those settings are the default behavior. The others can be turned on by individual command line options. If all of those semantic modes are in the states above, then we are in "unsafe-fp-math" mode. That's my proposal.

I've updated the patch to use the low level options as you suggested. In the current version of the patch I'm not currently checking explicitly `exception_behavior(ignore) &&  fenv_access(off)` given that the other modes of these properties seems to work only if overall there is the "precise" profile. I don't know if that's acceptable, or if instead the CC1 shouldn't make any assumption about the compiler driver doing the right thing.

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D136786/new/

https://reviews.llvm.org/D136786