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* [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG'.
@ 2022-05-07 9:56 chenglulu at loongson dot cn
2022-05-07 10:49 ` [Bug target/105514] " pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: chenglulu at loongson dot cn @ 2022-05-07 9:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105514
Bug ID: 105514
Summary: rv64 qsort gets wrong result when '-O2 -DDEBUG'.
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: chenglulu at loongson dot cn
Target Milestone: ---
Created attachment 52936
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52936&action=edit
riscv64-linux-gnu
%riscv64-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=riscv64-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/.../libexec/gcc/riscv64-linux-gnu/13.0.0/lto-wrapper
Target: riscv64-linux-gnu
Configured with: /.../configure --target=riscv64-linux-gnu --with-arch=rv64g
--with-abi=lp64d --enable-shared --disable-emultls --disable-bootstrap
--enable-languages=c,c++,fortran --disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.0.0 20220507 (experimental) (GCC)
There is no problem with the execution result of the following compiler.
% riscv64-linux-gnu-gcc qsort.c -o qsort -O2 --static -march=rv64g -mabi=lp64d
% ./qsort
./qsort
But, When I add a line to the code to print,program execution result is wrong.
% riscv64-linux-gnu-gcc qsort.c -o qsort -O2 --static -march=rv64g -mabi=lp64d
-DDEBUG
./qsort
test simple_qsort array with function pointer failed.
When add option '-DDEBUG -fno-reorder-blocks', The program execution result is
no problem again.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug target/105514] rv64 qsort gets wrong result when '-O2 -DDEBUG'. 2022-05-07 9:56 [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG' chenglulu at loongson dot cn @ 2022-05-07 10:49 ` pinskia at gcc dot gnu.org 2022-05-09 1:19 ` chenglulu at loongson dot cn ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-05-07 10:49 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105514 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Just looking at the code, there seems to be some aliasing violations going on which is causing the problem. Sometimes accessing via unsigned long and others by double. Does -fno-strict-aliasing fixes the issue? ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/105514] rv64 qsort gets wrong result when '-O2 -DDEBUG'. 2022-05-07 9:56 [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG' chenglulu at loongson dot cn 2022-05-07 10:49 ` [Bug target/105514] " pinskia at gcc dot gnu.org @ 2022-05-09 1:19 ` chenglulu at loongson dot cn 2022-05-09 8:06 ` rguenth at gcc dot gnu.org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: chenglulu at loongson dot cn @ 2022-05-09 1:19 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105514 --- Comment #2 from chenglulu <chenglulu at loongson dot cn> --- (In reply to Andrew Pinski from comment #1) > Just looking at the code, there seems to be some aliasing violations going > on which is causing the problem. > > Sometimes accessing via unsigned long and others by double. > > Does -fno-strict-aliasing fixes the issue? After adding the compile option '-fno-strict-aliasing', the program runs without problems. But I don't understand why one print affects so much? Thanks! ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/105514] rv64 qsort gets wrong result when '-O2 -DDEBUG'. 2022-05-07 9:56 [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG' chenglulu at loongson dot cn 2022-05-07 10:49 ` [Bug target/105514] " pinskia at gcc dot gnu.org 2022-05-09 1:19 ` chenglulu at loongson dot cn @ 2022-05-09 8:06 ` rguenth at gcc dot gnu.org 2022-05-12 2:10 ` chenglulu at loongson dot cn 2022-05-12 2:29 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: rguenth at gcc dot gnu.org @ 2022-05-09 8:06 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105514 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED Target| |riscv --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- indeed strict aliasing violation ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/105514] rv64 qsort gets wrong result when '-O2 -DDEBUG'. 2022-05-07 9:56 [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG' chenglulu at loongson dot cn ` (2 preceding siblings ...) 2022-05-09 8:06 ` rguenth at gcc dot gnu.org @ 2022-05-12 2:10 ` chenglulu at loongson dot cn 2022-05-12 2:29 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: chenglulu at loongson dot cn @ 2022-05-12 2:10 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105514 chenglulu <chenglulu at loongson dot cn> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|INVALID |FIXED --- Comment #4 from chenglulu <chenglulu at loongson dot cn> --- (In reply to Richard Biener from comment #3) > indeed strict aliasing violation Ok,thanks! ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug target/105514] rv64 qsort gets wrong result when '-O2 -DDEBUG'. 2022-05-07 9:56 [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG' chenglulu at loongson dot cn ` (3 preceding siblings ...) 2022-05-12 2:10 ` chenglulu at loongson dot cn @ 2022-05-12 2:29 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2022-05-12 2:29 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105514 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|FIXED |INVALID --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- . ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-05-12 2:29 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-05-07 9:56 [Bug c/105514] New: rv64 qsort gets wrong result when '-O2 -DDEBUG' chenglulu at loongson dot cn 2022-05-07 10:49 ` [Bug target/105514] " pinskia at gcc dot gnu.org 2022-05-09 1:19 ` chenglulu at loongson dot cn 2022-05-09 8:06 ` rguenth at gcc dot gnu.org 2022-05-12 2:10 ` chenglulu at loongson dot cn 2022-05-12 2:29 ` pinskia at gcc dot gnu.org
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