public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug target/103773] New: wrong code at -Oz due to sign extension
@ 2021-12-20 12:47 zsojka at seznam dot cz
2021-12-20 14:03 ` [Bug target/103773] " roger at nextmovesoftware dot com
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: zsojka at seznam dot cz @ 2021-12-20 12:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
Bug ID: 103773
Summary: wrong code at -Oz due to sign extension
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: zsojka at seznam dot cz
CC: roger at nextmovesoftware dot com
Target Milestone: ---
Host: x86_64-pc-linux-gnu
Target: x86_64-pc-linux-gnu
Created attachment 52034
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52034&action=edit
reduced testcase
Output:
$ x86_64-pc-linux-gnu-gcc -Oz testcase.c
$ ./a.out
Aborted
$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r12-6072-20211220084313-g8d1e342b4af-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-isl --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
--with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r12-6072-20211220084313-g8d1e342b4af-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.0 20211220 (experimental) (GCC)
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/103773] wrong code at -Oz due to sign extension
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
@ 2021-12-20 14:03 ` roger at nextmovesoftware dot com
2021-12-20 14:21 ` jakub at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: roger at nextmovesoftware dot com @ 2021-12-20 14:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
Roger Sayle <roger at nextmovesoftware dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |roger at nextmovesoftware dot com
Last reconfirmed| |2021-12-20
Ever confirmed|0 |1
Status|UNCONFIRMED |ASSIGNED
--- Comment #1 from Roger Sayle <roger at nextmovesoftware dot com> ---
Sorry. Mine. Bootstrapping and regression testing a fix now.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/103773] wrong code at -Oz due to sign extension
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
2021-12-20 14:03 ` [Bug target/103773] " roger at nextmovesoftware dot com
@ 2021-12-20 14:21 ` jakub at gcc dot gnu.org
2021-12-21 15:32 ` roger at nextmovesoftware dot com
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jakub at gcc dot gnu.org @ 2021-12-20 14:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Also:
int a;
void
foo (void)
{
a = -42;
}
which corrupts some random unrelated memory.
For the TARGET_64BIT movsi case, it needs to be done only if the destination is
a register rather than MEM.
Mostly unrelated, I wonder if we shouldn't have a separate TYPE_PUSHPOP, decide
in the (set (attr "type") and then just emit it and get e.g. the "length"
attribute right for it.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/103773] wrong code at -Oz due to sign extension
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
2021-12-20 14:03 ` [Bug target/103773] " roger at nextmovesoftware dot com
2021-12-20 14:21 ` jakub at gcc dot gnu.org
@ 2021-12-21 15:32 ` roger at nextmovesoftware dot com
2021-12-21 15:50 ` zsojka at seznam dot cz
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: roger at nextmovesoftware dot com @ 2021-12-21 15:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
--- Comment #3 from Roger Sayle <roger at nextmovesoftware dot com> ---
Patch proposed
https://gcc.gnu.org/pipermail/gcc-patches/2021-December/587258.html
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/103773] wrong code at -Oz due to sign extension
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
` (2 preceding siblings ...)
2021-12-21 15:32 ` roger at nextmovesoftware dot com
@ 2021-12-21 15:50 ` zsojka at seznam dot cz
2021-12-23 12:36 ` cvs-commit at gcc dot gnu.org
2021-12-27 17:31 ` roger at nextmovesoftware dot com
5 siblings, 0 replies; 7+ messages in thread
From: zsojka at seznam dot cz @ 2021-12-21 15:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
--- Comment #4 from Zdenek Sojka <zsojka at seznam dot cz> ---
(In reply to Roger Sayle from comment #3)
> Patch proposed
> https://gcc.gnu.org/pipermail/gcc-patches/2021-December/587258.html
Thank you for the patch. Does it work correctly with the red zone? I am asking
since the "mov" instruction normally doesn't affect stack, and I don't see any
indication that the "push" alternative does. But I definitely do not have
enough knowledge about the GCC internals.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/103773] wrong code at -Oz due to sign extension
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
` (3 preceding siblings ...)
2021-12-21 15:50 ` zsojka at seznam dot cz
@ 2021-12-23 12:36 ` cvs-commit at gcc dot gnu.org
2021-12-27 17:31 ` roger at nextmovesoftware dot com
5 siblings, 0 replies; 7+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-12-23 12:36 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Roger Sayle <sayle@gcc.gnu.org>:
https://gcc.gnu.org/g:ef26c151c14a87177d46fd3d725e7f82e040e89f
commit r12-6106-gef26c151c14a87177d46fd3d725e7f82e040e89f
Author: Roger Sayle <roger@nextmovesoftware.com>
Date: Thu Dec 23 12:33:07 2021 +0000
x86: PR target/103773: Fix wrong-code with -Oz from pop to memory.
This is a fix to PR target/103773 where -Oz shouldn't use push/pop
on x86 to shrink writing small integer constants to memory.
Instead clang uses "andl $0, mem" for writing zero, and "orl $-1, mem"
when writing -1 to memory when using -Oz. This patch implements this
via peephole2 where we can confirm that its ok to clobber the flags.
2021-12-23 Roger Sayle <roger@nextmovesoftware.com>
Uroš Bizjak <ubizjak@gmail.com>
gcc/ChangeLog
PR target/103773
* config/i386/i386.md (*mov<mode>_and): New define_insn for
writing a zero to memory using AND.
(*mov<mode>_or): Extend to allow memory destination and HImode.
(*movdi_internal): Remove -Oz push/pop optimization from here.
(*movsi_internal): Likewise.
(peephole2): Perform -Oz push/pop optimization here, only for
register destinations, values other than zero, and in functions
that don't used the red zone.
(peephole2): With -Oz, convert writes of 0 or -1 to memory into
their clobber forms, i.e. *mov<mode>_and and *mov<mode>_or resp.
gcc/testsuite/ChangeLog
PR target/103773
* gcc.target/i386/pr103773-2.c: New test case.
* gcc.target/i386/pr103773.c: New test case.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug target/103773] wrong code at -Oz due to sign extension
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
` (4 preceding siblings ...)
2021-12-23 12:36 ` cvs-commit at gcc dot gnu.org
@ 2021-12-27 17:31 ` roger at nextmovesoftware dot com
5 siblings, 0 replies; 7+ messages in thread
From: roger at nextmovesoftware dot com @ 2021-12-27 17:31 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103773
Roger Sayle <roger at nextmovesoftware dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Target Milestone|--- |12.0
Resolution|--- |FIXED
--- Comment #6 from Roger Sayle <roger at nextmovesoftware dot com> ---
This shoud now be fixed on mainline.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2021-12-27 17:31 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-12-20 12:47 [Bug target/103773] New: wrong code at -Oz due to sign extension zsojka at seznam dot cz
2021-12-20 14:03 ` [Bug target/103773] " roger at nextmovesoftware dot com
2021-12-20 14:21 ` jakub at gcc dot gnu.org
2021-12-21 15:32 ` roger at nextmovesoftware dot com
2021-12-21 15:50 ` zsojka at seznam dot cz
2021-12-23 12:36 ` cvs-commit at gcc dot gnu.org
2021-12-27 17:31 ` roger at nextmovesoftware dot com
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).