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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/114872] [13/14/15 Regression] Miscompilation with -O2 after commit r13-8037
Date: Mon, 06 May 2024 17:29:07 +0000 [thread overview]
Message-ID: <bug-114872-4-XYtBMjogF3@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114872-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114872
--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Dmitrii Pasechnik from comment #12)
> A colleague disassembled, using ghidra (https://ghidra-sre.org/), the
> results of the compilations with, respectively, -O2 and with -O0 flags.
> Comparing the results, in the broken (built with -O2) case one sees a
> miscompilation of a call to GAP_CallFunc3Args - it is called with one
> argument less than it should, three instead of four!
>
> broken (-O2):
>
> > plVar9 = (long *)GAP_CallFunc3Args(*(undefined8 *)(param_1 + 0x20),local_a0[4],
> > local_a8[4]);
>
> vs. good (-O0):
>
> < LAB_0013cbd9:
> < plVar10 = (long *)GAP_CallFunc3Args(*(undefined8 *)(param_1 +
> 0x20),local_a8[4],
> < local_a0[4],plVar16[4]);
>
> And this is despite the prototype for calling GAP_CallFunc3Args() is
> found in "gap/libgap-api.h", which is included in example.c as #include
> "gap/libgap-api.h", meant to be respected during the compilation.
>
> I hope this helps in chasing down the obvious compiler bug. Perhaps it can
> be also seen without disassembling, simply on the intermediate data
> generated by the compiler.
Both calls pass 4 arguments, both in optimized -O2 -fPIC GCC 13.2.1 dump and in
assembly:
movq -88(%rbp), %rdx
movq %r12, %rcx
movq %r13, %rsi
movq %rax, %rdi
call GAP_CallFunc3Args@PLT
...
movq -88(%rbp), %rdx
movq %r12, %rcx
movq %r13, %rsi
movq %rax, %rdi
call GAP_CallFunc3Args@PLT
and
GAP_CallFunc3Args (_53, _47, __pyx_v_func_54(D), _49);
...
_441 = GAP_CallFunc3Args (_98, _97, _96, _95);
next prev parent reply other threads:[~2024-05-06 17:29 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-27 18:57 [Bug c/114872] New: Miscompilation with -O2 after commit 049ec9b981d1f4f97736061d5cf7d0ae990b57d7 arojas at archlinux dot org
2024-04-27 18:59 ` [Bug c/114872] " arojas at archlinux dot org
2024-04-27 19:03 ` pinskia at gcc dot gnu.org
2024-04-27 19:05 ` pinskia at gcc dot gnu.org
2024-04-27 19:06 ` arojas at archlinux dot org
2024-04-27 20:00 ` [Bug tree-optimization/114872] [13/14/15 Regression] Miscompilation with -O2 after commit r13-8037 pinskia at gcc dot gnu.org
2024-04-29 15:53 ` sjames at gcc dot gnu.org
2024-04-29 16:00 ` jakub at gcc dot gnu.org
2024-04-29 20:05 ` arojas at archlinux dot org
2024-05-01 1:00 ` sjames at gcc dot gnu.org
2024-05-01 1:01 ` sjames at gcc dot gnu.org
2024-05-01 1:01 ` sjames at gcc dot gnu.org
2024-05-01 1:03 ` sjames at gcc dot gnu.org
2024-05-03 11:07 ` dima.pasechnik at cs dot ox.ac.uk
2024-05-03 11:26 ` dima.pasechnik at cs dot ox.ac.uk
2024-05-06 13:53 ` slyfox at gcc dot gnu.org
2024-05-06 17:29 ` jakub at gcc dot gnu.org [this message]
2024-05-06 17:59 ` jakub at gcc dot gnu.org
2024-05-06 21:41 ` slyfox at gcc dot gnu.org
2024-05-06 22:08 ` slyfox at gcc dot gnu.org
2024-05-06 22:45 ` dima.pasechnik at cs dot ox.ac.uk
2024-05-07 10:45 ` jakub at gcc dot gnu.org
2024-05-07 11:05 ` slyfox at gcc dot gnu.org
2024-05-07 22:13 ` slyfox at gcc dot gnu.org
2024-05-08 8:18 ` slyfox at gcc dot gnu.org
2024-05-08 8:27 ` rguenth at gcc dot gnu.org
2024-05-08 18:10 ` slyfox at gcc dot gnu.org
2024-05-08 19:17 ` dima.pasechnik at cs dot ox.ac.uk
2024-05-08 19:35 ` pinskia at gcc dot gnu.org
2024-05-08 19:58 ` jakub at gcc dot gnu.org
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