OpenMP/Fortran: Combined directives with map/firstprivate of same symbol

This patch fixes a case where a combined directive (e.g. "!$omp target
parallel ...") contains both a map and a firstprivate clause for the
same variable.  When the combined directive is split into two nested
directives, the outer "target" gets the "map" clause, and the inner
"parallel" gets the "firstprivate" clause, like so:

  !$omp target parallel map(x) firstprivate(x)

  -->

  !$omp target map(x)
    !$omp parallel firstprivate(x)
      ...

When there is no map of the same variable, the firstprivate is distributed
to both directives, e.g. for 'y' in:

  !$omp target parallel map(x) firstprivate(y)

  -->

  !$omp target map(x) firstprivate(y)
    !$omp parallel firstprivate(y)
      ...

This is not a recent regression, but appear to fix a long-standing ICE.
(The included testcase is based on one by Tobias.)

2022-12-06  Julian Brown  <julian@codesourcery.com>

gcc/fortran/
	* trans-openmp.cc (gfc_add_firstprivate_if_unmapped): New function.
	(gfc_split_omp_clauses): Call above.

libgomp/
	* testsuite/libgomp.fortran/combined-directive-splitting-1.f90: New
	test.

1 files changed, 41 insertions, 0 deletions

diff --git a/libgomp/testsuite/libgomp.fortran/combined-directive-splitting-1.f90 b/libgomp/testsuite/libgomp.fortran/combined-directive-splitting-1.f90
new file mode 100644
index 0000000..e662a2b
--- /dev/null
+++ b/libgomp/testsuite/libgomp.fortran/combined-directive-splitting-1.f90
@@ -0,0 +1,41 @@
+module m
+  integer :: a = 1
+  !$omp declare target enter(a)
+end module m
+
+module m2
+contains
+subroutine bar()
+  use m
+  implicit none
+  !$omp declare target
+  a = a + 5
+end subroutine bar
+end module m2
+
+program p
+  use m
+  use m2
+  implicit none
+  integer :: b, i
+
+  !$omp target parallel do map(always, tofrom: a) firstprivate(a)
+    do i = 1, 1
+      a = 7
+      call bar()
+      if (a /= 7) error stop 1
+      a = a + 8
+    end do
+  if (a /= 6) error stop 2
+
+  b = 3
+  !$omp target parallel do map(always, tofrom: a) firstprivate(b)
+    do i = 1, 1
+      a = 3
+      call bar ()
+      if (a /= 8) error stop 3
+      a = a + b
+    end do
+  if (a /= 11) error stop 4
+end program p
+