------- Additional Comments From law at redhat dot com 2005-02-10 18:01 ------- Subject: Re: [4.0 Regression] Poor quality code after loop unrolling.
On Thu, 2005-02-10 at 12:12 +0100, Zdenek Dvorak wrote: > > In comment #3 Zdenek said "Possibly even better would be to add generation > > of > > autoincrements to loop optimizer, but this would require fixing cse so that > > it > > handles them correctly." Zdenek, can you elaborate on why CSE needs > > fixing? > > cse does not handle autoincrements. I have no idea what's the problem > there, it is just what I was told when I asked for the possibility to > move the autoinc creation pass last time. Anyone has more precise > information about the nature of the problem? It's been about a decade since I looked at cse vs autoincrements, so the details have faded from memory. [The original context I found the problem was in an attempt to run cse after reload. ] Anyway, from a 30 second look at CSE the first thing that jumps out at me is I don't think we would invalidate objects in the hash table which are auto-incremented. Jeff -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19078