On March 2, 2015 5:32:27 AM CET, Kugan <kugan.vivekanandara...@linaro.org> wrote: >On 02/03/15 15:29, Jeff Law wrote: >> On 03/01/15 16:32, Kugan wrote: >>> In linaro-4.9-branch, with the following (reduced) test case, I run >into >>> a situation where loop_latch_edge is NULL during jump threading. I >am >>> wondering if this a possible during jump threading or the error >lies >>> some where else? I can't reproduce it with the trunk. >> There's really no way to tell without a lot more information. If you >> can't reproduce on the 4.9 branch or the trunk, then you're likely >going >> to have to do the real digging. >> >> THe first thing I tend to do with these things is to draw the CFG and >> annotate it with all the jump threading paths. Then I look at how >the >> jump threading paths interact with each other and the loop structure, >> then reconcile that with the constraints placed on threading in >> tree-ssa-threadupdate.c. > >Thanks Jeff. I will do the same.
You might want to look at trunk fixes to loop preserving code. Istr some cfg hook fixes. The loop latch test is definitely wrong. Richard. >Kugan
