[Bug middle-end/80995] New: Fortran OpenACC kernels "Unhandled stmt in entry/exit: _14 = BUILTIN_EXPECT ([...])" after "Introduce fortran loop preheader"

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80995

            Bug ID: 80995
           Summary: Fortran OpenACC kernels "Unhandled stmt in entry/exit:
                    _14 = BUILTIN_EXPECT ([...])" after "Introduce fortran
                    loop preheader"
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Keywords: openacc
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: vries at gcc dot gnu.org
  Target Milestone: ---

Merging trunk r237533 "Introduce fortran loop preheader" into gomp-4-branch
r240825, there are two regressions in Fortran OpenACC kernels parallelization:

    PASS: gfortran.dg/goacc/kernels-loop-n.f95   -O   scan-tree-dump-not
parloops1 "FAILED:"
    PASS: gfortran.dg/goacc/kernels-loop-n.f95   -O   scan-tree-dump-times
optimized "(?n);; Function __test_MOD_foo._omp_fn.0 " 1
    [-PASS:-]{+FAIL:+} gfortran.dg/goacc/kernels-loop-n.f95   -O  
scan-tree-dump-times parloops1 "(?n)oacc function \\(0," 1
    PASS: gfortran.dg/goacc/kernels-loop-n.f95   -O   scan-tree-dump-times
parloops1 "SUCCESS: may be parallelized" 1
    PASS: gfortran.dg/goacc/kernels-loop-n.f95   -O  (test for excess errors)

    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -O0  execution test
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -O1  (test for excess errors)
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -O1  execution test
    [-PASS:-]{+FAIL:+} libgomp.oacc-fortran/non-scalar-data.f90
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2  (test
for excess errors)
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -O2  execution test
    [-PASS:-]{+FAIL:+} libgomp.oacc-fortran/non-scalar-data.f90
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O3
-fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions 
(test for excess errors)
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions  execution test
    [-PASS:-]{+FAIL:+} libgomp.oacc-fortran/non-scalar-data.f90
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -O3 -g 
(test for excess errors)
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -O3 -g  execution test
    [-PASS:-]{+FAIL:+} libgomp.oacc-fortran/non-scalar-data.f90
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none  -Os  (test
for excess errors)
    PASS: libgomp.oacc-fortran/non-scalar-data.f90 -DACC_DEVICE_TYPE_nvidia=1
-DACC_MEM_SHARED=0 -foffload=nvptx-none  -Os  execution test

   
[...]/source-gcc/libgomp/testsuite/libgomp.oacc-fortran/non-scalar-data.f90: In
function 'kernels_._omp_fn.1':
   
[...]/source-gcc/libgomp/testsuite/libgomp.oacc-fortran/non-scalar-data.f90:35:0:
warning: OpenACC kernels construct will be executed sequentially; will by
default avoid offloading to prevent data copy penalty

For both these (I looked at "-O2" only), the issue is: "Unhandled stmt in
entry/exit: _14 = BUILTIN_EXPECT (_13, 1, 41);".  I'm not sure whether
"BUILTIN_EXPECT" should simply be added to be handled in
"gcc/tree-parloops.c:oacc_entry_exit_ok_1", or if it should already have been
accepted by one of the existing cases in there, or if it in fact shouldn't
appear there, should have been folded away earlier on.