[FFmpeg-devel] [RFC]configures asmalign test does not work on icc64 11.0

[Carl Eugen Hoyos]

Reimar D?ffinger <Reimar.Doeffinger <at> stud.uni-karlsruhe.de> writes:

> > configure tests alignment with the following C program:
> > __asm__ (".align 3");
> > icc 11.0 for x86-64 optimizes the align away (even with -O0),
> 
> "optimizes the align away"? How

$ gcc -S align.c -o -
        .file   "align.c"
#APP
        .align 3
        .ident  "GCC: (SUSE Linux) 4.3.1 20080507 (prerelease)
[gcc-4_3-branch revision 135036]"
        .section        .note.GNU-stack,"", at progbits

$ icc -S align.c -o - && cat ./-
# -- Machine type EFI2
# mark_description "Intel(R) C++ Compiler Professional for applications
running on Intel(R) 64,Version 11.0    Build 20081105 %";
# mark_description "s";
# mark_description "-S -o -";
        .file "align.c"
        .data
        .section .note.GNU-stack, ""
# End

> /why?

How do I know;-)

> Have you tried replacing 3 with 9?

No changes.

> Or adding a "volatile" and "::memory" to the asm statement?

volatile helps as does simply putting the asm statement into a function
declaration.

Carl Eugen