[Bug rtl-optimization/83095] New: [8 regression] many tests fail starting with r255001

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83095

            Bug ID: 83095
           Summary: [8 regression] many tests fail starting with r255001
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at gcc dot gnu.org
  Target Milestone: ---

This is on powerpc64 BE only.  I am not seeing the failures on LE.

Failing test cases (note that they are all compiled with -Os, -O2 and other -O
values work):

> FAIL: gcc.c-torture/execute/20041218-1.c   -Os  execution test
> FAIL: gcc.c-torture/execute/pr51877.c   -Os  execution test
> FAIL: gcc.dg/atomic/stdatomic-generic.c   -Os  execution test
> FAIL: gfortran.dg/aliasing_dummy_1.f90   -Os  execution test
> FAIL: gfortran.dg/array_function_5.f90   -Os  execution test
> FAIL: gfortran.dg/dependency_25.f90   -Os  execution test
> FAIL: gfortran.dg/derived_constructor_comps_5.f90   -Os  execution test
> FAIL: gfortran.dg/derived_constructor_comps_6.f90   -Os  execution test
> FAIL: gfortran.dg/derived_init_2.f90   -Os  execution test
> FAIL: gfortran.dg/dtio_7.f90   -Os  execution test
> FAIL: gfortran.dg/matmul_3.f90   -Os  execution test
> FAIL: gfortran.dg/mvbits_7.f90   -Os  execution test
> FAIL: gfortran.dg/select_type_39.f03   -Os  execution test
> FAIL: gfortran.dg/unlimited_polymorphic_1.f03   -Os  execution test

I looked through a couple of them and they are failing when some value is not
what is expected and abort is called.

Looking at the first one:

seurer@makalu-lp1:~/gcc/build/gcc-test2$
/home/seurer/gcc/build/gcc-test2/gcc/xgcc
-B/home/seurer/gcc/build/gcc-test2/gcc/
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.c-torture/execute/20041218-1.c 
-fno-diagnostics-show-caret -fdiagnostics-color=never    -Os  -w  -lm    -o
./20041218-1.exe

seurer@makalu-lp1:~/gcc/build/gcc-test2$ ./20041218-1.exe 
Aborted (core dumped)

seurer@makalu-lp1:~/gcc/build/gcc-test2$
/home/seurer/gcc/build/gcc-test2/gcc/xgcc
-B/home/seurer/gcc/build/gcc-test2/gcc/
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.c-torture/execute/20041218-1.c 
-fno-diagnostics-show-caret -fdiagnostics-color=never  -g  -Os  -w  -lm    -o
./20041218-1.exe

seurer@makalu-lp1:~/gcc/build/gcc-test2$ gdb ./20041218-1.exe 
(gdb) run
Program received signal SIGABRT, Aborted.
0x00003fffb7cd129c in .raise () from /lib64/libc.so.6
Missing separate debuginfos, use: debuginfo-install glibc-2.17-196.el7.ppc64
(gdb) where
#0  0x00003fffb7cd129c in .raise () from /lib64/libc.so.6
#1  0x00003fffb7cd34a8 in .abort () from /lib64/libc.so.6
#2  0x0000000010000764 in check (x=<optimized out>, x@entry=0x10000a34,
y=<optimized out>, y@entry=0x10010fd8 <v.2810+8>)
    at
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.c-torture/execute/20041218-1.c:51
#3  0x00000000100007e0 in bar (y=<optimized out>, x=1) at
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.c-torture/execute/20041218-1.c:72
#4  0x0000000010000520 in foo (z=<synthetic pointer>, y=1, x=<synthetic
pointer>) at
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.c-torture/execute/20041218-1.c:94
#5  main () at
/home/seurer/gcc/gcc-test2/gcc/testsuite/gcc.c-torture/execute/20041218-1.c:115