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From: "tnfchris at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/108583] [13 Regression] wrong code with vector division
 by uint16 at -O2
Date: Tue, 31 Jan 2023 11:39:01 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108583

--- Comment #10 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
(In reply to rsandifo@gcc.gnu.org from comment #9)
> Are we sure this is a vectoriser vs. C vectors thing?

it's not, the issue we're debating is how to fix it.

As Richi pointed out https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108583#=
c4 we
can fix the vectorizer case by adding a guard around the recog code in the
vectorizer.

But that only fixes the vectorizer, and Richi asked why that wasn't enough,=
 to
which I pointed out it's because intrinsics code hits it as well.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108583#c5

This is why I mentioned that there are two ways to fix this:

1. We make the hook less general, and add checks in every place it is calle=
d.
2. We keep the hook general and pass enough context to the hook for it to
decide how to optimize the division.

it's not intrinsics only, but a vectorizer only fix won't fix intrinsics.=