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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114660] Exponentiating by squaring not
 performed for x * y * y * y * y
Date: Tue, 09 Apr 2024 18:07:56 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D114660

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2024-04-09
     Ever confirmed|0                           |1

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> We don't do as much reassociation as we should with signed integers due to
> overflow. If you use -fwrapv, you get the reassociation; I am 99% sure th=
ere
> is a dup for this bug too.

I should say we also do it for unsigned already (see PR 95867), -fwrapv cas=
e we
just treat signed similar to unsigned here. Anyways what needs to happen is=
 we
need 2 levels of gimple, one with signed integer overflow behavior and then=
 one
with wrapping behavior. RTL does not distinguish between signed and unsigned
behaviors for many operations (plus and multiple) so we get some optimizati=
ons
there but not all.=