------- Comment #9 from dnovillo at google dot com 2007-09-27 14:12 ------- Subject: Re: [4.3 Regression] aggregate DSE disabled
On 27 Sep 2007 14:01:18 -0000, rguenther at suse dot de <[EMAIL PROTECTED]> wrote: > I sort-of agree. Still DCE was able to handle tree-ssa/complex-4.c > before we removed V_MUST_DEF. Which is what I'm trying to get back. Yeah, it is somewhat tempting to make the infrastructure more powerful because you suddenly get more out of seemingly innocent passes. However, a more powerful infrastructure creates problems of its own, it needs to be maintained and it causes slowdowns even in passes that do not need all the expressive power. > As "good enough" UD web it would be nice to have only single VDEFs on > stores (I don't care for clobbers at call sites). Though finding the > optimal static partitioning to ensure this is probably hard? Yeah, that is the whole motivation behind the dynamic aspects of mem-ssa, but getting it right has proven tricky. Unfortunately, I have not had time to come back to that idea in some time. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33562
