"Jiahua He" <[EMAIL PROTECTED]> wrote on 12/02/2007 22:54:08:
> Oh, I see. For reduction and induction, you don't need to deal with > the condition with vdef. I am considering how to implement an idiom > with vdef, like SCAN (prefix sum). And by the way, do you support > idioms with vuses? > You mean detecting this pattern?: for i a[i] += a[i-1]; I don't know if analyzing vdefs/vuses would help you much to detect this pattern - maybe you're better off computing the dependence-distance (i.e. use compute_data_dependences_for_loop, and look at DDR_DIST_VECTS). dorit > Jiahua > > > 2007/2/12, Dorit Nuzman <[EMAIL PROTECTED]>: > > > Thanks! In fact, I should ask how to deal with idiom (such as > > > reduction, induction) recognition for virtual defs/uses. > > > > > > > Just curious - what is this for? (are you interested in this in the context > > of vectorization? is there a specific example you have in mind?) > > > > dorit > > > > > Jiahua > > > > > > > > > 2007/2/12, Daniel Berlin <[EMAIL PROTECTED]>: > > > > On 2/12/07, Jiahua He <[EMAIL PROTECTED]> wrote: > > > > > Hi, > > > > > > > > > > I am reading the code of autovect branch and curious about how to > > deal > > > > > with the dependencies of virtual defs/uses. In the function > > > > > vect_analyze_scalar_cycles( ), I found the statement "Skip virtual > > > > > phi's. The data dependences that are associated with virtual > > defs/uses > > > > > ( i.e., memory accesses) are analyzed elsewhere." But where is the > > > > > code? I tried to search for "vect_induction_def" and > > > > > "vect_reduction_def" and found that they are not used to assign > > > > > elsewhere. Is the analysis not implemented yet? Thanks in advance! > > > > > > > > They show up as data references because of tree-data-reference.c > > > marking them. > > > > At lets, that's how other linear loop transforms handles it. > > > > Not sure about how vectorizer deals with it specifically > > > > > > > > > > > > > > Jiahua > > > > > > > > > > > > >
