[PATCH] Fix PR69760

[H.J. Lu]

On Wed, Feb 24, 2016 at 6:49 AM, Richard Biener <rguenther@suse.de> wrote:
>
> The following fixes bogus SCEV analysis for expressions that are only
> executed conditionally [note: conditionally here doesn't include
> after a taken exit].  Basically we have to make sure further analysis
> does not attempt to use undefined overflow for expressions we don't
> know whether they are computed in the original source (for all
> loop iterations).  This would result in bogus CHRECs as can be seen
> in this PR.
>
> The solution is to re-write those expressions in a way so overflow
> behavior is well-defined.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
>
> Richard.
>
> 2016-02-24  Richard Biener  <rguenther@suse.de>
>         Jakub Jelinek  <jakub@redhat.com>
>
>         PR middle-end/69760
>         * tree-scalar-evolution.c (interpret_rhs_expr): Re-write
>         conditionally executed ops to well-defined overflow behavior.
>

This caused:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69983


-- 
H.J.