[Bug target/105922] autovectorizer does not handle fp exceptions correctly for SVE

rguenth at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Tue Jun 14 07:38:30 GMT 2022


Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
           Keywords|                            |wrong-code

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> Confirmed. The division should have been predicated on the same as the
> load/store but currently GCC does not do that.
> GCC does not really support looking into fpu status bits or exceptions while
> vectorizing either.

It effectively "supports" it by failing to vectorize when exception state
builtins are used in the vectorized region and otherwise it just accumulates
exception bits (but it doesn't support in-order traps if you enable exceptions
to trap).

Note there's a bit of confusion as to what exactly controls FP exception
bit correctness and the documentation should probably be clarified.

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