On Mon, Nov 15, 2010 at 11:12 AM, Jakub Jelinek <ja...@redhat.com> wrote:
>
> Ah, the problem is that memory_identifier_string is only initialized in
> ipa-reference.c's initialization, so it can be (and is in this case) NULL in
> ipa-pure-const.c.
Ok. And I guess you can verify that all versions of gcc do this
correctly for "asm volatile"?
Because since we'll have to work around this problem in the kernel, I
suspect the simplest solution is to remove the "+m" that causes
register pressure problems, and then use "asm volatile" to work around
the const-function bug.
And add a large comment about why "asm volatile" is probably always a
good idea when you have a memory clobber and don't have any other
visible memory modifications.
I do wonder if this explains some of the problems we had with the
bitop asms too.
Hmm?
Linus
