On Jun 19, 2007, at 10:54 AM, Chris Lattner wrote: >>>> I don't see a better way so I guess this will be a targetinstrinfo >>>> bit (true for those with side-effects). >>> >>> Okay, the tricky thing here is instructions that have "conditional >>> side effects". For example, all instructions marked isload/isstore/ >>> iscall etc should be considered to have side effects (as would >>> anything with implicit definitions), but loads from constant pools >>> and other special cases should not be considered to have side >>> effects. >> >> Calls should definitely be marked to have side-effects. To me the >> tricky cases are loads / stores. But can't we determine these from >> the operands? So, add one more condition: >> 3. if memory operation, no external symbol or global address inputs. >> >> Then we don't need to mark loads / stores as having side effects. > > Ah right, even better. So you're saying we don't need a new flag at > all?
We do need a "hasSideEffect" flag. There are some non-branch, non- load/store instructions that have side effects, no? > > I guess this won't work right now though, because we don't model > things that clobber the condcodes. Wouldn't it be nice if we did? :) Yeah, I hear you. It's coming. Those flag clobbering instructions just have to be marked "hasSideEffect" for now. 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
