------- Comment #35 from dberlin at gcc dot gnu dot org 2006-11-10 00:12 ------- Subject: Re: [4.3 Regression] Misscompilation of spec2006 gcc
> Take the above case. > If we simply use virtual variable versions to value number memory, we > will believe that *a and *b are possible stores to the same piece of > memory, even though they are not. In case it's not clear, this means while previously you would have determined you can move *b above *a simply by looking at the RHS, you can't anymore. My guess: Any memory optimization that wants to just eliminate redundant loads will be just fine with mem-ssa,. Any memory optimization that wants to eliminate redundant stores will have to be redesigned to not use chains to get maximum precision. Any memory optimization that wants to hoist either loads or stores will have to be redesigned to not use chains to determine where things can be moved to, in order to get maximum precision. At least, that's the way it appears to me. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29680
