optimization/6007: cfg cleanup tremendous performance hog with -O1

[lucier@math.purdue.edu]

I just filed

optimization/6007: cfg cleanup tremendous performance hog with -O1

http://gcc.gnu.org/ml/gcc-prs/2002-03/msg00729.html

It addresses the problem that cfg cleanup takes *way* too long to
run, and it's invoked with -O1.  This is a tremendous regression from
2.95*, and I ask that it be added to the list of 3.1 release issues.

I've been filing PRs for this since at least last August.

Right now, neither 3.1 nor 3.2 bootstraps on Solaris.  I don't see how
I and other people are going to have enough opportunity to test 3.1
on sparc/Solaris before release to ensure that things work even
minimally.  (For example, the last time I tried -fprofile-arcs
-ftest-coverage/gcov, it didn't work.)  Jakub just marked PR 5740
as fixed, and I haven't had an opportunity to test it, since sparc/Solaris
hasn't bootstrapped since he sent me the patch privately.

Blah.

Brad