Fortran: Add 'omp scan' support of OpenMP 5.0

gcc/fortran/ChangeLog:

	* dump-parse-tree.c (show_omp_clauses, show_omp_node,
	show_code_node): Handle OMP SCAN.
	* gfortran.h (enum gfc_statement): Add ST_OMP_SCAN.
	(enum): Add OMP_LIST_SCAN_IN and OMP_LIST_SCAN_EX.
	(enum gfc_exec_op): Add EXEC_OMP_SCAN.
	* match.h (gfc_match_omp_scan): New prototype.
	* openmp.c (gfc_match_omp_scan): New.
	(gfc_match_omp_taskgroup): Cleanup.
	(resolve_omp_clauses, gfc_resolve_omp_do_blocks,
	omp_code_to_statement, gfc_resolve_omp_directive): Handle 'omp scan'.
	* parse.c (decode_omp_directive, next_statement,
	gfc_ascii_statement): Likewise.
	* resolve.c (gfc_resolve_code): Handle EXEC_OMP_SCAN.
	* st.c (gfc_free_statement): Likewise.
	* trans-openmp.c (gfc_trans_omp_clauses, gfc_trans_omp_do,
	gfc_split_omp_clauses): Handle 'omp scan'.

libgomp/ChangeLog:

	* testsuite/libgomp.fortran/scan-1.f90: New test.

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/reduction4.f90: Update; move FE some tests to ...
	* gfortran.dg/gomp/reduction6.f90: ... this new test and ...
	* gfortran.dg/gomp/reduction7.f90: ... this new test.
	* gfortran.dg/gomp/reduction5.f90: Add dg-error.
	* gfortran.dg/gomp/scan-1.f90: New test.
	* gfortran.dg/gomp/scan-2.f90: New test.
	* gfortran.dg/gomp/scan-3.f90: New test.
	* gfortran.dg/gomp/scan-4.f90: New test.
	* gfortran.dg/gomp/scan-5.f90: New test.
	* gfortran.dg/gomp/scan-6.f90: New test.
	* gfortran.dg/gomp/scan-7.f90: New test.

1 files changed, 36 insertions, 4 deletions

diff --git a/gcc/fortran/trans-openmp.c b/gcc/fortran/trans-openmp.c
index 6b4ad6a..ae29064 100644
--- a/gcc/fortran/trans-openmp.c
+++ b/gcc/fortran/trans-openmp.c
@@ -2334,6 +2334,12 @@ gfc_trans_omp_clauses (stmtblock_t *block, gfc_omp_clauses *clauses,
 	case OMP_LIST_NONTEMPORAL:
 	  clause_code = OMP_CLAUSE_NONTEMPORAL;
 	  goto add_clause;
+	case OMP_LIST_SCAN_IN:
+	  clause_code = OMP_CLAUSE_INCLUSIVE;
+	  goto add_clause;
+	case OMP_LIST_SCAN_EX:
+	  clause_code = OMP_CLAUSE_EXCLUSIVE;
+	  goto add_clause;
 
 	add_clause:
 	  omp_clauses
@@ -4707,7 +4713,31 @@ gfc_trans_omp_do (gfc_code *code, gfc_exec_op op, stmtblock_t *pblock,
   code->exit_label = NULL_TREE;
 
   /* Main loop body.  */
-  tmp = gfc_trans_omp_code (code->block->next, true);
+  if (clauses->lists[OMP_LIST_REDUCTION_INSCAN])
+    {
+      gcc_assert (code->block->next->next->op == EXEC_OMP_SCAN);
+      gcc_assert (code->block->next->next->next->next == NULL);
+      locus *cloc = &code->block->next->next->loc;
+      location_t loc = gfc_get_location (cloc);
+
+      gfc_code code2 = *code->block->next;
+      code2.next = NULL;
+      tmp = gfc_trans_code (&code2);
+      tmp = build2 (OMP_SCAN, void_type_node, tmp, NULL_TREE);
+      SET_EXPR_LOCATION (tmp, loc);
+      gfc_add_expr_to_block (&body, tmp);
+      input_location = loc;
+      tree c = gfc_trans_omp_clauses (&body,
+				      code->block->next->next->ext.omp_clauses,
+				      *cloc);
+      code2 = *code->block->next->next->next;
+      code2.next = NULL;
+      tmp = gfc_trans_code (&code2);
+      tmp = build2 (OMP_SCAN, void_type_node, tmp, c);
+      SET_EXPR_LOCATION (tmp, loc);
+    }
+  else
+    tmp = gfc_trans_omp_code (code->block->next, true);
   gfc_add_expr_to_block (&body, tmp);
 
   /* Label for cycle statements (if needed).  */
@@ -5234,13 +5264,15 @@ gfc_split_omp_clauses (gfc_code *code,
 	  = code->ext.omp_clauses->lists[OMP_LIST_LASTPRIVATE];
       /* Reduction is allowed on simd, do, parallel and teams.
 	 Duplicate it on all of them, but omit on do if
-	 parallel is present.  */
+	 parallel is present; additionally, inscan applies to do/simd only.  */
       for (int i = OMP_LIST_REDUCTION; i <= OMP_LIST_REDUCTION_TASK; i++)
 	{
-	  if (mask & GFC_OMP_MASK_TEAMS)
+	  if (mask & GFC_OMP_MASK_TEAMS
+	      && i != OMP_LIST_REDUCTION_INSCAN)
 	    clausesa[GFC_OMP_SPLIT_TEAMS].lists[i]
 	      = code->ext.omp_clauses->lists[i];
-	  if (mask & GFC_OMP_MASK_PARALLEL)
+	  if (mask & GFC_OMP_MASK_PARALLEL
+	      && i != OMP_LIST_REDUCTION_INSCAN)
 	    clausesa[GFC_OMP_SPLIT_PARALLEL].lists[i]
 	      = code->ext.omp_clauses->lists[i];
 	  else if (mask & GFC_OMP_MASK_DO)