Major bootstrap time regression on March 30

[Steven Bosscher]

Hi,

We have a bootstrap time regression since March 30.  Bootstrap times
on Diego Novillo's SPEC box went up from (an already high)  5500s to
almost 8000s, see:
http://people.redhat.com/dnovillo/spec2000/gcc/gcc-compiler-build-secs_elapsed.png

On IRC a patch possibly causing this regression was mentioned: the
subvars correctness changes from Dan. He also posted a heuristics
change patch a day earlier, which has not been reviewed yet, see:
http://gcc.gnu.org/ml/gcc-patches/2005-03/msg02666.html.  If the
subvars patch really is the problem, this heuristics patch should
fix it.

Could someone (hi, Diego!) review Dan's patch?  And if that patch
does not fix this, we'll have to look for someone else to blame ;-)

Gr.
Steven