[Bug c/126412] [17 Regression] csmith: wrong code with -O3 -march=arm-32 -fno-strict-aliasing

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126412

--- Comment #4 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Sam James from comment #3)
> No, that's your CHOST, it's not what =native is going to detect.

Presumably what you want is somewhere in amongst this lot:

$ ~/gcc/results/bin/gcc -c -march=native -v bug1109.c
Using built-in specs.
COLLECT_GCC=/home/dcb/gcc/results/bin/gcc
Target: arm-linux-gnueabihf
Configured with: ../trunk/configure
--prefix=/home/dcb/gcc/results.20260724.asan --disable-bootstrap --disable-doc
--disable-multilib --with-build-config=bootstrap-asan
--with-pkgversion=b5e6f5d2d435aba7 --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 20260724 (experimental) (b5e6f5d2d435aba7) 
COLLECT_GCC_OPTIONS='-c'  '-v' '-mfloat-abi=hard' '-mfpu=neon-fp-armv8'
'-mtls-dialect=gnu'  '-marm' '-mlibarch=armv8.2-a+fp16+dotprod'
'-march=armv8.2-a+fp16+dotprod'
 /home/dcb/gcc/results.20260724.asan/libexec/gcc/arm-linux-gnueabihf/17.0.0/cc1
-quiet -v -imultilib . -imultiarch arm-linux-gnueabihf bug1109.c -quiet
-dumpbase bug1109.c -dumpbase-ext .c -mfloat-abi=hard -mfpu=neon-fp-armv8
-mtls-dialect=gnu -marm -mlibarch=armv8.2-a+fp16+dotprod
-march=armv8.2-a+fp16+dotprod -version -o /tmp/ccbBGYPq.s
GNU C23 (b5e6f5d2d435aba7) version 17.0.0 20260724 (experimental)
(arm-linux-gnueabihf)
        compiled by GNU C version 14.2.0, GMP version 6.3.0, MPFR version
4.2.2, MPC version 1.3.1, isl version none
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
ignoring nonexistent directory "/usr/local/include/arm-linux-gnueabihf"
ignoring nonexistent directory
"/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/include-fixed/arm-linux-gnueabihf"
ignoring nonexistent directory
"/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/../../../../arm-linux-gnueabihf/include"
#include "..." search starts here:
#include <...> search starts here:
 /home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/include
 /usr/local/include
 /home/dcb/gcc/results.20260724.asan/include

/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/include-fixed
 /usr/include/arm-linux-gnueabihf
 /usr/include
End of search list.
Compiler executable checksum: 5bd0d52eafbc3a1c20aa7c3ea60d178e
COLLECT_GCC_OPTIONS='-c'  '-v' '-mfloat-abi=hard' '-mfpu=neon-fp-armv8'
'-mtls-dialect=gnu'  '-marm' '-mlibarch=armv8.2-a+fp16+dotprod'
'-march=armv8.2-a+fp16+dotprod'
 as -v -march=armv8.2-a+fp16+dotprod -mfloat-abi=hard -mfpu=neon-fp-armv8
-meabi=5 -o bug1109.o /tmp/ccbBGYPq.s
GNU assembler version 2.44 (arm-linux-gnueabihf) using BFD version (GNU
Binutils for Raspbian) 2.44
COMPILER_PATH=/home/dcb/gcc/results.20260724.asan/libexec/gcc/arm-linux-gnueabihf/17.0.0/:/home/dcb/gcc/results.20260724.asan/libexec/gcc/arm-linux-gnueabihf/17.0.0/:/home/dcb/gcc/results.20260724.asan/libexec/gcc/arm-linux-gnueabihf/:/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/:/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/
LIBRARY_PATH=/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/:/home/dcb/gcc/results.20260724.asan/lib/gcc/arm-linux-gnueabihf/17.0.0/../../../:/lib/arm-linux-gnueabihf/:/lib/:/usr/lib/arm-linux-gnueabihf/:/usr/lib/
COLLECT_GCC_OPTIONS='-c'  '-v' '-mfloat-abi=hard' '-mfpu=neon-fp-armv8'
'-mtls-dialect=gnu'  '-marm' '-mlibarch=armv8.2-a+fp16+dotprod'
'-march=armv8.2-a+fp16+dotprod'
$ 

I have also started a reduction, using this script:

(rm -f ./a.out && /usr/bin/gcc -w bug1231B.c && ./a.out 1) | grep "checksum
after hashing g_13 : E841B57E" || exit 1

(rm -f ./a.out && ~/gcc/results/bin/gcc -w -O3  -march=native 
-fno-strict-aliasing bug1231B.c && ./a.out 1) | grep "checksum after hashing
g_13 : ABA3CCFC" || exit 1

exit 0