[Bug testsuite/81699] New: [8 regression] gcc.dg/tree-ssa/reassoc-23.c fails starting with r250853

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81699

            Bug ID: 81699
           Summary: [8 regression] gcc.dg/tree-ssa/reassoc-23.c fails
                    starting with r250853
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at gcc dot gnu.org
  Target Milestone: ---

I saw this on both powerpc64 LE and BE power8 systems.

spawn -ignore SIGHUP /home/seurer/gcc/build/gcc-test2/gcc/xgcc
-B/home/seurer/gcc/build/gcc-test2/gcc/
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.dg/tree-ssa/reassoc-23.c
-fno-diagnostics-show-caret -fdiagnostics-color=never -O2 -fdump-tree-reassoc1
-S -o reassoc-23.s
PASS: gcc.dg/tree-ssa/reassoc-23.c (test for excess errors)
FAIL: gcc.dg/tree-ssa/reassoc-23.c scan-tree-dump-times reassoc1 "= 20" 1
testcase /home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.dg/tree-ssa/tree-ssa.exp
completed in 1 seconds

                === gcc Summary ===

# of expected passes            1
# of unexpected failures        1


>From comparing the dumps before and after I think everything is OK but the test
case needs to be adjusted:


seurer@makalu-lp1:~/gcc/build/gcc-test2$ diff
reassoc-23.c.123t.reassoc1.r250852 reassoc-23.c.123t.reassoc1.r250853
13,17d12
<   unsigned int j;
<   unsigned int i;
<   unsigned int _2;
<   unsigned int _10;
< 
19,22c14
<   _2 = -c_5(D);
<   _10 = -a_4(D);
<   e_8 = 20;
<   return e_8;
---
>   return 20;