------- Comment #18 from amylaar at gcc dot gnu dot org 2009-01-12 18:09 ------- (In reply to comment #17) > I think enabling partial PRE to do it is appropriate (with at most inserting > on one edge).
I think the abstraction with tree-ssa and cfglayout mode has gone too far. We no longer have visibility of the costs of branches, or of opportunities for conditional execution. I suspect that the 35% speed regressions we see on EEMBC fbital at -O3 are also to blame on overzealous tree-pre partial-partial redundancy eliminations. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38401