[Bug middle-end/38474] slow compilation at -O0 due to expand's temp slot goo

[matz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38474

--- Comment #62 from Michael Matz <matz at gcc dot gnu.org> 2012-06-26 14:44:58 UTC ---
(In reply to comment #61)
> (In reply to comment #57)
> 
> Anyway, on the machine where are debugged this, compilation at -O3
> took over 16 seconds which dropped to about 13.5 seconds when I also

What?  Must be a future machine.  On everything I have access to the reduced
testcase (6309 lines) takes about 800 to 1000 seconds.  Do you build without
any checking?

In any case, the proposed patch does reduce the time to basically nothing for
the alias tree walker, so: thanks :)