[Bug tree-optimization/83836] New: [8 regression] gcc.dg/vect/pr79920.c FAILs

["ro at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83836

            Bug ID: 83836
           Summary: [8 regression] gcc.dg/vect/pr79920.c FAILs
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: rsandifo at gcc dot gnu.org
  Target Milestone: ---
            Target: sparc-sun-solaris2.*, also on arm-none-eabi,
                    arm-none-linux-gnueabi, ia64-suse-linux-gnu,
                    mips64el-unknown-linux-gnu

Between 20180112 (r256571) and 20180114 (r256664), the gcc.dg/vect/pr79920.c
test started to FAIL on a couple of targets:

+FAIL: gcc.dg/vect/pr79920.c -flto -ffat-lto-objects  scan-tree-dump-times vect
"using an in-order \\\\(fold-left\\\\) reduction" 1 (found 0 times)
+FAIL: gcc.dg/vect/pr79920.c scan-tree-dump-times vect "using an in-order
\\\\(fold-left\\\\) reduction" 1 (found 0 times)

I'm seeing it on Solaris/SPARC, but several others are also affected according
to gcc-testresults postings.

This is most likely caused by r256639:
2018-01-13  Richard Sandiford  <richard.sandiford@linaro.org>
            Alan Hayward  <alan.hayward@arm.com>
            David Sherwood  <david.sherwood@arm.com>
[...]
gcc/testsuite/
[...]
        * gcc.dg/vect/pr79920.c: Expect both loops to be vectorized and
        check for a message about using in-order reductions.

  Rainer