OpenMP: Add 'omp requires' to Fortran (mostly parsing)

gcc/fortran/ChangeLog:

	* gfortran.h (enum gfc_statement): Add ST_OMP_REQUIRES.
	(enum gfc_omp_requires_kind): New.
	(enum gfc_omp_atomic_op): Add GFC_OMP_ATOMIC_ACQ_REL.
	(struct gfc_namespace): Add omp_requires and omp_target_seen.
	(gfc_omp_requires_add_clause,
	(gfc_check_omp_requires): New.
	* match.h (gfc_match_omp_requires): New.
	* module.c (enum ab_attribute, attr_bits): Add omp requires clauses.
	(mio_symbol_attribute): Read/write them.
	* openmp.c (gfc_check_omp_requires, (gfc_omp_requires_add_clause,
	gfc_match_omp_requires): New.
	(gfc_match_omp_oacc_atomic): Use requires's default mem-order.
	* parse.c (decode_omp_directive): Match requires, set omp_target_seen.
	(gfc_ascii_statement): Handle ST_OMP_REQUIRES.
	* trans-openmp.c (gfc_trans_omp_atomic): Handle GFC_OMP_ATOMIC_ACQ_REL.

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/requires-1.f90: New test.
	* gfortran.dg/gomp/requires-2.f90: New test.
	* gfortran.dg/gomp/requires-3.f90: New test.
	* gfortran.dg/gomp/requires-4.f90: New test.
	* gfortran.dg/gomp/requires-5.f90: New test.
	* gfortran.dg/gomp/requires-6.f90: New test.
	* gfortran.dg/gomp/requires-7.f90: New test.
	* gfortran.dg/gomp/requires-8.f90: New test.
	* gfortran.dg/gomp/requires-9.f90: New test.

1 files changed, 50 insertions, 3 deletions

diff --git a/gcc/fortran/parse.c b/gcc/fortran/parse.c
index 96fd4aa..6669621 100644
--- a/gcc/fortran/parse.c
+++ b/gcc/fortran/parse.c
@@ -995,6 +995,9 @@ decode_omp_directive (void)
 	      ST_OMP_PARALLEL_WORKSHARE);
       matcho ("parallel", gfc_match_omp_parallel, ST_OMP_PARALLEL);
       break;
+    case 'r':
+      matcho ("requires", gfc_match_omp_requires, ST_OMP_REQUIRES);
+      break;
     case 's':
       matcho ("sections", gfc_match_omp_sections, ST_OMP_SECTIONS);
       matcho ("section", gfc_match_omp_eos_error, ST_OMP_SECTION);
@@ -1086,6 +1089,38 @@ decode_omp_directive (void)
 	  return ST_NONE;
 	}
     }
+  switch (ret)
+    {
+    case ST_OMP_DECLARE_TARGET:
+    case ST_OMP_TARGET:
+    case ST_OMP_TARGET_DATA:
+    case ST_OMP_TARGET_ENTER_DATA:
+    case ST_OMP_TARGET_EXIT_DATA:
+    case ST_OMP_TARGET_TEAMS:
+    case ST_OMP_TARGET_TEAMS_DISTRIBUTE:
+    case ST_OMP_TARGET_TEAMS_DISTRIBUTE_SIMD:
+    case ST_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO:
+    case ST_OMP_TARGET_TEAMS_DISTRIBUTE_PARALLEL_DO_SIMD:
+    case ST_OMP_TARGET_PARALLEL:
+    case ST_OMP_TARGET_PARALLEL_DO:
+    case ST_OMP_TARGET_PARALLEL_DO_SIMD:
+    case ST_OMP_TARGET_SIMD:
+    case ST_OMP_TARGET_UPDATE:
+      {
+	gfc_namespace *prog_unit = gfc_current_ns;
+	while (prog_unit->parent)
+	  {
+	    if (gfc_state_stack->previous
+		&& gfc_state_stack->previous->state == COMP_INTERFACE)
+	      break;
+	    prog_unit = prog_unit->parent;
+	  }
+	  prog_unit->omp_target_seen = true;
+	break;
+      }
+    default:
+      break;
+    }
   return ret;
 
  do_spec_only:
@@ -1604,7 +1639,8 @@ next_statement (void)
 /* OpenMP declaration statements.  */
 
 #define case_omp_decl case ST_OMP_THREADPRIVATE: case ST_OMP_DECLARE_SIMD: \
-  case ST_OMP_DECLARE_TARGET: case ST_OMP_DECLARE_REDUCTION
+  case ST_OMP_DECLARE_TARGET: case ST_OMP_DECLARE_REDUCTION: \
+  case ST_OMP_REQUIRES
 
 /* Block end statements.  Errors associated with interchanging these
    are detected in gfc_match_end().  */
@@ -2407,6 +2443,9 @@ gfc_ascii_statement (gfc_statement st)
     case ST_OMP_PARALLEL_WORKSHARE:
       p = "!$OMP PARALLEL WORKSHARE";
       break;
+    case ST_OMP_REQUIRES:
+      p = "!$OMP REQUIRES";
+      break;
     case ST_OMP_SECTIONS:
       p = "!$OMP SECTIONS";
       break;
@@ -6516,10 +6555,18 @@ done:
     }
   while (changed);
 
-  /* Fixup for external procedures.  */
+  /* Fixup for external procedures and resolve 'omp requires'.  */
+  int omp_requires;
+  omp_requires = 0;
+  for (gfc_current_ns = gfc_global_ns_list; gfc_current_ns;
+       gfc_current_ns = gfc_current_ns->sibling)
+    {
+      omp_requires |= gfc_current_ns->omp_requires;
+      gfc_check_externals (gfc_current_ns);
+    }
   for (gfc_current_ns = gfc_global_ns_list; gfc_current_ns;
        gfc_current_ns = gfc_current_ns->sibling)
-    gfc_check_externals (gfc_current_ns);
+    gfc_check_omp_requires (gfc_current_ns, omp_requires);
 
   /* Do the parse tree dump.  */
   gfc_current_ns = flag_dump_fortran_original ? gfc_global_ns_list : NULL;