Georg-Johann Lay <avr@xxxxxxxx> writes:
> Hi, gcc generates wrong code when it aliases symbols like in (For a
> complete test cases cf. PR92606):
>
> static const __attribute((progmem)) int xyz_prog[] = { 123, 123, 123 };
> int xyz[] = { 123, 123, 123 };
>
> for target avr. xyz and xyz_prog are binary the same, but the program
> accesses them with different instructions (LPM for the 1st to read from
> flash, LD in the 2nd case to read from RAM).
>
> The bug is that the compiler issues
>
> .section .progmem.data,"a",@progbits
> .type xyz_prog, @object
> .size xyz_prog, 12
> xyz_prog:
> .byte 123
> ...
> .set xyz,xyz_prog
>
> which is obviously wrong because the symbols MUST NOT alias each other.
>
> As I failed to find the target hook that disables such aliasing; please
> would someone point me to it?
I agree it doesn't look like there is one. Sounds like a useful
hook to add though.
Thanks,
Richard
>
> Johann
>
>
> FYI, the generated code is also wrong with names address spaces:
>
> static const __flash int xyz_prog[] = { 123, 123, 123 };
> int xyz[] = { 123, 123, 123 };
>
> again, PR92606 has a test case:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92606#c3
