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From: "djordje.baljozovic at ac dot rwth-aachen.de"
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To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/115345] [12/13/14/15 Regression] Different outputs
 compared to GCC 11- and MSVC/Clang
Date: Tue, 04 Jun 2024 18:43:24 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D115345

--- Comment #11 from Djordje Baljozovic <djordje.baljozovic at ac dot rwth-=
aachen.de> ---
(In reply to Djordje Baljozovic from comment #9)
> (In reply to Andrew Pinski from comment #7)
> > A few questions, does `-fsanitize=3Dundefined -fsanitize=3Daddress` rep=
ort
> > anything? Does it work at -O0 and not just -O3? Does adding
> > -fno-strict-aliasing to the command line "fix" the crash? Are there any
> > warnings with `-Wextra -Wall` that might be causing an issue?
>=20
> Have not tested -O0 and -fno-strict-aliasing; will let you know if this
> fixed the problem.
> No warnings with -Wextra -Wall to my knowledge.
>=20
> Sincerely,
> George

Hi Andrew and Jakub,
The results are more than interesting:

1. -fno-strict-aliasing: none of the inputs processed (with O3)
2. O0: all but one input processed
3. O3: none of the inputs processed
4. O1 and O2: all inputs processed without any issues -- this did it.

Now the question is: how on Earth did O1/O2 do the trick, and not O0?!

Once again, thanks a lot for your detailed and quick responses.
George
P.S. I will keep @Jakub's bisect idea in mind if something like this happen=
s in
the future.=