https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126412
Bug ID: 126412
Summary: csmith: wrong code with -O3 -march=arm-32
-fno-strict-aliasing
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: dcb314 at hotmail dot com
Target Milestone: ---
Created attachment 65130
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65130&action=edit
C source code
The attached code does this on a 32 bit Raspberry PI:
$ for i in ~/gcc/results.202607*/bin/gcc; do echo $i; $i -O3 -march=native
-fno-strict-aliasing -w bug1231B.c && ./a.out ; done
/home/dcb/gcc/results.20260704.asan/bin/gcc
checksum = 49DDD2CA
/home/dcb/gcc/results.20260707.asan/bin/gcc
checksum = 49DDD2CA
/home/dcb/gcc/results.20260711.asan/bin/gcc
checksum = 6BA0A111
/home/dcb/gcc/results.20260718.asan/bin/gcc
checksum = 6BA0A111
/home/dcb/gcc/results.20260724.asan/bin/gcc
checksum = 6BA0A111
$
Compilers are:
$ /home/dcb/gcc/results.20260707.asan/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/home/dcb/gcc/results.20260707.asan/bin/gcc
COLLECT_LTO_WRAPPER=/home/dcb/gcc/results.20260707.asan/libexec/gcc/arm-linux-gnueabihf/17.0.0/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../trunk/configure
--prefix=/home/dcb/gcc/results.20260707.asan --disable-bootstrap --disable-doc
--disable-multilib --with-build-config=bootstrap-asan
--with-pkgversion=9c36ceaacc080a70 --enable-checking=yes
--enable-languages=c,c++,fortran --with-cpu=cortex-a76 --with-fpu=neon-fp-armv8
--with-float=hard --build=arm-linux-gnueabihf --host=arm-linux-gnueabihf
--target=arm-linux-gnueabihf
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 17.0.0 20260704 (experimental) (9c36ceaacc080a70)
$
and
$ /home/dcb/gcc/results.20260711.asan/bin/gcc -v
Using built-in specs.
COLLECT_GCC=/home/dcb/gcc/results.20260711.asan/bin/gcc
COLLECT_LTO_WRAPPER=/home/dcb/gcc/results.20260711.asan/libexec/gcc/arm-linux-gnueabihf/17.0.0/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../trunk/configure
--prefix=/home/dcb/gcc/results.20260711.asan --disable-bootstrap --disable-doc
--disable-multilib --with-build-config=bootstrap-asan
--with-pkgversion=0a82c5e1187c68ac --enable-checking=yes
--enable-languages=c,c++,fortran --with-cpu=cortex-a76 --with-fpu=neon-fp-armv8
--with-float=hard --build=arm-linux-gnueabihf --host=arm-linux-gnueabihf
--target=arm-linux-gnueabihf
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 17.0.0 20260711 (experimental) (0a82c5e1187c68ac)
$
If I remove the -fno-strict-aliasing, everything seems ok.
This bug does not occur on x86_64.
