[Bug tree-optimization/104214] [12 regression] gcc.dg/vect/pr81196.c fails after r12-6844

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104214

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:2e211a02290f3b3533b56c593fc7b95edb8593b0

commit r12-6858-g2e211a02290f3b3533b56c593fc7b95edb8593b0
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jan 25 11:55:28 2022 +0100

    tree-optimization/104214 - amend PR100740 fix for pointer compares

    When we have a pointer relational compare we have stronger guarantees
    about overflow, in particular rewriting BASE0 + STEP0 cmp BASE1 + STEP1
    as BASE0 + STEP0 - STEP1 cmp BASE1 is always valid and the new IV0
    does not overflow.  The patch basically reverts the previous change
    when pointers are involved, keeping only the more conservative handling
    for equality compares which can involve comparing different object
    addresses.

    2022-01-25  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/104214
            * tree-ssa-loop-niter.cc (number_of_iterations_cond): Use
            stronger guarantees for relational pointer compares when
            rewriting BASE0 + STEP0 cmp BASE1 + STEP1 as
            BASE0 + STEP0 - STEP1 cmp BASE1.

            * gcc.dg/vect/pr81196-2.c: New variant testcase only
            requiring vect_int.