[Bug tree-optimization/87074] [8/9 Regression] Unroll and jam bug: O3 result differ from O2

[matz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87074

--- Comment #6 from Michael Matz <matz at gcc dot gnu.org> ---
Author: matz
Date: Sat Sep  1 17:33:45 2018
New Revision: 264030

URL: https://gcc.gnu.org/viewcvs?rev=264030&root=gcc&view=rev
Log:
Fix PR87074

        Backport from mainline
        PR tree-optimization/87074
        * gimple-loop-jam.c (unroll_jam_possible_p): Check loop exit
        PHIs for outer-loop uses.

testsuite/
        * gcc.dg/pr87074.c: New test.

Added:
    branches/gcc-8-branch/gcc/testsuite/gcc.dg/pr87074.c
Modified:
    branches/gcc-8-branch/gcc/ChangeLog
    branches/gcc-8-branch/gcc/gimple-loop-jam.c
    branches/gcc-8-branch/gcc/testsuite/ChangeLog