On Jun 19, 2007, at 9:40 AM, Chris Lattner wrote: > > On Jun 19, 2007, at 9:38 AM, Evan Cheng wrote: > >>>> If we are really concerned about the speed, then I agree the hybrid >>>> approach is the best. Sorry about the confusion. >>> >>> Speed is something to consider, but I don't think it should override >>> maintainability. >>> >>>> Not to mention I had already considered the "trivial >>>> rematerialization" >>>> scheme to be temporary. >>> >>> Okay, how do you think this should work going forward? >> >> Trivial remat will go away when proper remat is implemented. All >> instructions without side-effect will be rematerializable if their >> operands are available so all these will go away. Not that proper >> remat is coming anytime soon though. > > Ok. How do you intend to capture the "without side-effects" part? > > It seems that simple remat works for things that: > > 1. have no side effects > 2. have no register inputs > > Is there another condition?
Can't think of any. > > If so, simple remat can check #2 today, just by itself looking at the > machineinstr. Given that, it comes down to how we want to > represent #1. I don't see a better way so I guess this will be a targetinstrinfo bit (true for those with side-effects). Evan > > -Chris > _______________________________________________ > llvm-commits mailing list > llvm-commits@cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
