[Bug tree-optimization/71916] [6/7 Regression] ICE at -O3 on valid code on x86_64-linux-gnu in "maybe_record_trace_start"

[helloqirun at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71916

--- Comment #9 from Qirun Zhang <helloqirun at gmail dot com> ---
(In reply to Martin Liška from comment #7)
> Hm, the second test-case works fine with r233209, but started to fail with
> r236831:
> 
> Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
> Date:   Fri May 27 16:32:38 2016 +0000
> 
>         * tree-ssa-threadedge.c: Remove include of tree-ssa-threadbackward.h.
>         (thread_across_edge): Remove calls to find_jump_threads_backwards.
>         * passes.def: Add jump threading passes before DOM/VRP.
>         * tree-ssa-threadbackward.c (find_jump_threads_backwards): Change
>         argument to a basic block from an edge.  Remove tests which are
>         handled elsewhere.
>         (pass_data_thread_jumps, class pass_thread_jumps): New.
>         (pass_thread_jumps::gate, pass_thread_jumps::execute): New.
>         (make_pass_thread_jumps): Likewise.
>         * tree-pass.h (make_pass_thread_jumps): Declare.
>     
>         * gcc.dg/tree-ssa/pr21417.c: Update expected output.
>         * gcc.dg/tree-ssa/pr66752-3.c: Likewise.
>         * gcc.dg/tree-ssa/pr68198.c: Likewise.
>         * gcc.dg/tree-ssa/pr69196-1.c: Likewise.
>         * gcc.dg/tree-ssa/pr69270-3.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-2b.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-2g.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-2h.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-6.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-7.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-12.c: Likewise.
>         * gcc.dg/tree-ssa/ssa-dom-thread-13.c: Likewise.
>         * gcc.dg/tree-ssa/vrp56.c: Likewise.

Will it be a good idea to separate the two bugs (i.e., to create a new PR for
the second case)?