> The MEM form is more "canonical", so the loop SM machinery to detect > equality should be adjusted accordingly. Alternatively you can teach > PRE insertion to strip off the MEM if possible (though > fold_stmt_inplace should > arelady do this if possible).
Richard, Thank you! You are right. I noticed on latest trunk the problem in PRE was already fixed by invoking fold_stmt_inplace. Unfortunately for this small case, the latest trunk code still can't do SM for variable pos, because refs_may_alias_p(*D.4074_10, pos) is true, that is, pos has alias with l[pos]. I think alias analysis should be able to know they don't have alias with each other, unless there is an assignment statement like "l=&pos;". Can alias analysis fix the problem? Thanks, -Jiangning > > Richard. >
