[FFmpeg-devel] [PATCH] fix h264_deblock_sse2.asm segfaults on clang/x86-32

[Reimar Döffinger]

On Tue, Aug 31, 2010 at 07:06:09PM -0400, Ronald S. Bultje wrote:
> on fate/clang/freebsd/x86-32 [1], all h264 tests fail with a sigbus.
> There's some alignment issues in the sse2 asm. The asm appears to
> assume that the caller function guarantees a certain alignment, which
> is (IMO) not necessarily true. If the function is called directly from
> C, stack can have any alignment, depending on the compiler used, so
> the functions shouldn't assume any specific alignment imo.

We already use
attribute_align_arg
on the functions where it should be necessary since they are called
from outside code and use optimizations and the compiler
is supposed to keep sufficient alignment for all functions below.
If that's not the case we might at least have performance issues
with several other functions using aligned stack arguments,
so it depends on that if there's any point in trying to fix that.