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Re: loop_latch_edge is NULL during jump threading
- From: Kugan <kugan dot vivekanandarajah at linaro dot org>
- To: Jeff Law <law at redhat dot com>, gcc at gcc dot gnu dot org
- Date: Mon, 02 Mar 2015 15:32:27 +1100
- Subject: Re: loop_latch_edge is NULL during jump threading
- Authentication-results: sourceware.org; auth=none
- References: <54F3A189 dot 2050102 at linaro dot org> <54F3E727 dot 60701 at redhat dot com>
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.
Kugan