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[Bug debug/61033] [4.8/4.9 Regression] Infinite loop in variable tracking
- From: "michael.collison at linaro dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 21 May 2015 02:09:54 +0000
- Subject: [Bug debug/61033] [4.8/4.9 Regression] Infinite loop in variable tracking
- Auto-submitted: auto-generated
- References: <bug-61033-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61033
Michael Collison <michael.collison at linaro dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|michael.collison at linaro dot org |mkuvyrkov at gcc dot gnu.org
--- Comment #12 from Michael Collison <michael.collison at linaro dot org> ---
GCC is looping infinitely in attempting to solve a data flow problem in
vt_find_locations. My working theory is that compute_bb_dataflow is incorrectly
asserting some value has changed. I have reduced my case to a candidate set of
basic blocks and a (candiate) RTL location this is continually removed/added.
The rtl location is:
dataflow difference found: removal of:
name: D#255
offset 0
(mem/f/c:SI (value/u:SI 106:3955 @0x22cb2f8/0x23424a0) [3 result.d+0 S4
A32])
I understand that the argument to 'VALUE" is a cselib_val_struct but I don't
know how to map this back to a insn that is causing the problem. Any thoughts
on how I might debug thus further?