[Bug tree-optimization/59651] [4.9 Regression] Vectorizer failing to spot dependence causes incorrect code generation.

[bmei at broadcom dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59651

--- Comment #5 from Bingfeng Mei <bmei at broadcom dot com> ---
Created attachment 31559
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31559&action=edit
initial patch

Hi, Tejas, vect_create_cond_for_alias_checks contains a bug in handling
negative step. The computed data access range should be shifted by
TYPE_SIZE_UNIT of bytes. Could you test the attached patch on aarch64 (I don't
have simulation environment setup)? Meanwhile I will check whether there is any
regression on x86-64. If everything is right, I am going to submit the patch.
Thanks.