[Bug tree-optimization/84512] [8 Regression] Missed optimization: should be precalculated in compile-time

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84512

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue Feb 27 15:25:33 2018
New Revision: 258036

URL: https://gcc.gnu.org/viewcvs?rev=258036&root=gcc&view=rev
Log:
2018-02-27  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/84512
        * tree-vect-loop.c (vect_compute_single_scalar_iteration_cost):
        Do not use the estimate returned from record_stmt_cost for
        the scalar iteration cost but sum properly using add_stmt_cost.

        * gcc.dg/tree-ssa/pr84512.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr84512.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vect-loop.c