On Thu, 2011-10-06 at 09:47 +0200, Paolo Bonzini wrote: > And IIUC the other address is based on pseudo 125 as well, but the > combination is (plus (plus (reg 126) (reg 128)) (const_int X)) and > cannot be represented on ppc. I think _this_ is the problem, so I'm > afraid your patch could cause pessimizations on x86 for example. On > x86, which has a cheap REG+REG+CONST addressing mode, it is much better > to propagate pseudo 125 so that you can delete the set altogether. > > However, indeed there is no downstream pass that undoes the > transformation. Perhaps we can do it in CSE, since this _is_ CSE after > all. :) The attached untested (uncompiled) patch is an attempt. > > Paolo
Thanks, Paolo! This makes good sense. I will play with your (second :) patch and let you know how it goes. Bill
