On Wed, Apr 20, 2016 at 5:08 PM, Bin Cheng <bin.ch...@arm.com> wrote:
> Hi,
> As reported in PR70715, GCC failed to prove no-overflows of IV(&p[n]) for
> simple example like:
> int
> foo (char *p, unsigned n)
> {
> while(n--)
> {
> p[n]='A';
> }
> return 0;
> }
> Actually, code has already been added to handle this form loops when fixing
> PR68529. Problem with this case is loop niter analyzer records control_IV
> with its base expanded by calling expand_simple_operations. This patch
> simply adds code expanding BASE before we check its equality against
> control_IV.base. In the long run, we might want to remove the use of
> expand_simple_operations.
>
> Bootstrap and test on x86_64. Is it OK?
Ok.
Richard.
> Thanks,
> bin
>
>
> 2016-04-20 Bin Cheng <bin.ch...@arm.com>
>
> PR tree-optimization/70715
> * tree-ssa-loop-niter.c (loop_exits_before_overflow): Check equality
> after expanding BASE using expand_simple_operations.
