[Bug tree-optimization/81661] [7/8 Regression] ICE in gimplify_modify_expr, at gimplify.c:5638

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81661

--- Comment #7 from rguenther at suse dot de <rguenther at suse dot de> ---
On Sat, 28 Oct 2017, pinskia at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81661
> 
> --- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
> (In reply to Richard Biener from comment #5)
> > One possibility is instead of using
> > 
> >  may_be_zero ? 0 : niter
> > 
> > as niter for code-generation use
> > 
> >  (may_be_zero ? 0 : 1) * niter
> > 
> > This avoids the gimplification issue.  We assemble this as
> > 
> >         call    __addvsi3
> >         movl    %eax, %esi
> >         subl    %ebp, %esi
> >         cmpl    %ebp, %eax
> >         setge   %al
> >         movzbl  %al, %eax
> >         imull   %eax, %esi
> > 
> > so it definitely is ugly (we're lacking any pattern matching on this
> > turning it back to a COND_EXPR).
> 
> r250377 added a pattern which should have caught that ...

I suspect we're missing cond ? 0 : 1 -> (int) cond for it to
trigger.