------- Additional Comments From stevenb at suse dot de 2005-03-06 09:30 ------- Subject: Re: [meta-bug] optimizations that CSE still catches
On Sunday 06 March 2005 06:59, law at redhat dot com wrote: > Ah. Yes. What did it look like in the tree dumps? Unless > one of the expanders is creating the negation I would think this > would be pretty easy to catch in fold-const.c This is PR20130. We don't fold -1*x to -x, ie. we never fold the MULT_EXPR to a NEGATE_EXPR. PR20130 has a patch. > expand_mult? Sigh. That's been in the back of my mind for a couple > years now -- it's probably one of the largest RTL expanders which > needs to have a lot of its functionality moved into trees. That'd be nice. In this case, Roger found out that for DImode negative constants it completely bypasses expand_mult_const. Fixing that would help for now. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19721
