[PATCH] D92059: [SLP] Control maximum vectorization factor from TTI

[Jordan Rupprecht via Phabricator via llvm-commits]

rupprecht added a comment.

In D92059#2525888 <https://reviews.llvm.org/D92059#2525888>, @rampitec wrote:

> In D92059#2525818 <https://reviews.llvm.org/D92059#2525818>, @rupprecht wrote:
>
>> This commit seems to be causing some internal test failures (raising a SIGFPE). I'm working on getting more details or a reduced test case to share. Is disabling this with `-mllvm -slp-max-vf=1` generally OK as a short term workaround? That seems to disable enough bits that the tests pass with that, but I'm not sure if there are other implications by setting that.
>
> Which tests are these? Setting the option to 1 effectively disables vectorization.

Sorry, forgot to followup: the issue ended up being due to use of `feenableexcept() with the default `-ffp-exception-behavior=ignore` -- so, saying to div-by-zero errors at runtime, but saying the compiler can assume it won't be raised at build configuration time. The crashing instruction was `divpd  %xmm0,%xmm12`, and the SIGFPE came from a div-by-zero on one of the unused slots in the packed value. The team is just removing `feenableexcept()` which fixes the issue. No action needed here :)


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https://reviews.llvm.org/D92059