[PATCH PR83695]Fix ICE by resetting cached scev info after interchange.

[Richard Biener]

On Thu, Jan 11, 2018 at 1:49 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
> Hi,
> As explained in comment of PR83695, outdated cached scev info could be referred
> by later interchange of outer loops in nest.  This simple patch fixes ICE by
> resetting cached scev info after interchange.  It's expensive resetting all scev
> information but might not be a problem here given we only interchange in limited
> cases.
>
> Bootstrap and test on x86_64 and AArch64.  Is it OK?

Ok.

Richard.

> Thanks,
> bin
>
> 2018-01-11  Bin Cheng  <bin.cheng@arm.com>
>
>         PR tree-optimization/83695
>         * gimple-loop-linterchange.cc
>         (tree_loop_interchange::interchange_loops): Call scev_reset_htab to
>         reset cached scev information after interchange.
>         (pass_linterchange::execute): Remove call to scev_reset_htab.
>
> gcc/testsuite
> 2018-01-11  Bin Cheng  <bin.cheng@arm.com>
>
>         PR tree-optimization/83695
>         * gcc.dg/tree-ssa/pr83695.c: New test.