https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116885
--- Comment #20 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jaroslav Fojtík from comment #0)
> jara@cfarm421:~/mintest$ make
> gcc -I./ -Wall -g -O2 -c struct.c -o struct.o
> gcc -I./ -Wall -g -O2 -c mintest.c -o mintest.o
> gcc -lm -o mintest struct.o mintest.o
>
> I have also tested option -O0 without any positive effect.
The commands above already use -O0 so that is not changing anything.
> <<<struct>>> (c)1998-2024 Jaroslav Fojtik
> This program tests the struct.c library
> ***LO_ENDIAN defined***
> ***NATIVE access***
> Testing struct manipulation
> Segmentation fault
If I use -fsanitize=undefined then I get a segfault on x86_64-pc-linux-gnu
using every version of GCC from 6.1 onwards. There are also errors reported by
valgrind.
Even without -fsanitize=undefined I see errors with GCC 13 on
x86_64-pc-linux-gnu in a Fedora 39 container:
<<<struct>>> (c)1998-2024 Jaroslav Fojtik
This program tests the struct.c library
***LO_ENDIAN defined***
***NATIVE access***
Testing struct manipulation
Wrong value read from struct SU.TileCompression 176, expected 2
Wrong value read from struct SU.TileByteCounts -1357445104, expected 2077093650
Wrong value read from struct SU.xRasMin 0.000000, expected -100.500000
Wrong value read from struct SU.Dummy "", expected "Hello word from struct
test".
Unit Error 4
(In reply to Jaroslav Fojtík from comment #17)
> All the previous GCCs from 2.95 till 13 did not crash on this and worked as
> expected.
That doesn't seem to be true. Both UBsan and valgrind reveal problems in the
code.
