Hi Christophe,
On 22/04/16 16:26, Christophe Lyon wrote:
On 21 April 2016 at 11:03, Richard Biener <richard.guent...@gmail.com> wrote:
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?
Hi Bin,
On ARM and AArch64 bare-metal toolchains, this causes
FAIL: gcc.dg/tree-ssa/minmax-2.c scan-tree-dump optimized "__builtin_fmin"
Are you sure it's Bins' patch? I've seen that test fail on aarch64-none-elf
since it was added recently.
See https://gcc.gnu.org/ml/gcc-patches/2016-04/msg01231.html
Kyrill
Christophe
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.
