Re: [Patch, updated] Make emulated TLS lto-friendly.

[Richard Henderson <rth at redhat dot com>]

On 07/13/2010 02:39 PM, Andrew Pinski wrote:
> On Tue, Jul 13, 2010 at 2:19 PM, Richard Henderson <rth@redhat.com> wrote:
>>
>> That change, however, alters the valid arguments to MEM_REF.  In that
>> &tlsvar is no longer valid.  Now, one could spend forever slightly
>> tweeking all of the myriad predicates involved, but what it comes down
>> to is that forwprop does not have the same checks that verify_expr does.
> 
> Hmm, this sounds like
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44824 where there are
> problems with ADDR_EXPR being inside MEM_REF in some other cases.

Yes, that's exactly the same problem: DLLIMPORT_P variables are
also !is_gimple_min_invariant, via !decl_address_invariant_p.

(Although for the life of me I can't tell you why -- the expansion
to *__imp_foo doesn't happen until rtl expansion time, and the value
is in fact function invariant (initialized at load time, like .got).
I tried to do a bit of spelunking to figure out the change history,
but svn blame -rN doesn't seem to work with files that are no longer
present at HEAD.)


r~