openmp: Add C/C++ support for "omp unroll" directive

This commit implements the C and the C++ front end changes to support
the "omp unroll" directive.  The execution of the loop transformation
relies on the pass that has been added as a part of the earlier
Fortran patch.

gcc/c-family/ChangeLog:

	* c-gimplify.cc (c_genericize_control_stmt): Handle OMP_UNROLL.
	* c-omp.cc: Add "unroll" to omp_directives[].
	* c-pragma.cc: Add "unroll" to omp_pragmas_simd[].
	* c-pragma.h (enum pragma_kind): Add PRAGMA_OMP_UNROLL to
	pragma_kind and adjust PRAGMA_OMP__LAST_.
	(enum pragma_omp_clause): Add PRAGMA_OMP_CLAUSE_FULL and
	PRAGMA_OMP_CLAUSE_PARTIAL.

gcc/c/ChangeLog:

	* c-parser.cc (c_parser_omp_clause_name): Handle "full" and
	"partial" clauses.
	(check_no_duplicate_clause): Change return type to bool and
	return check result.
	(c_parser_omp_clause_unroll_full): New function for parsing
	the "unroll clause".
	(c_parser_omp_clause_unroll_partial): New function for
	parsing the "partial" clause.
	(c_parser_omp_all_clauses): Handle PRAGMA_OMP_CLAUSE_FULL
	and PRAGMA_OMP_CLAUSE_PARTIAL.
	(c_parser_nested_omp_unroll_clauses): New function for parsing
	"omp unroll" directives following another directive.
	(OMP_UNROLL_CLAUSE_MASK): New definition.
	(c_parser_omp_unroll): New function for parsing "omp unroll"
	loops that are not associated with another directive.
	(c_parser_omp_construct): Handle PRAGMA_OMP_UNROLL.
	* c-typeck.cc (c_finish_omp_clauses): Handle
	OMP_CLAUSE_UNROLL_FULL, OMP_CLAUSE_UNROLL_PARTIAL,
	and OMP_CLAUSE_UNROLL_NONE.

gcc/cp/ChangeLog:

	* cp-gimplify.cc (cp_gimplify_expr): Handle OMP_UNROLL.
	(cp_fold_r): Likewise.
	(cp_genericize_r): Likewise.
	* parser.cc (cp_parser_omp_clause_name): Handle "full" clause.
	(check_no_duplicate_clause): Change return type to bool and
	return check result.
	(cp_parser_omp_clause_unroll_full): New function for parsing
	the "unroll clause".
	(cp_parser_omp_clause_unroll_partial): New function for
	parsing the "partial" clause.
	(cp_parser_omp_all_clauses): Handle OMP_CLAUSE_UNROLL and
	OMP_CLAUSE_FULL.
	(cp_parser_nested_omp_unroll_clauses): New function for parsing
	"omp unroll" directives following another directive.
	(cp_parser_omp_for_loop): Handle "omp unroll" directives
	between directive and loop.
	(OMP_UNROLL_CLAUSE_MASK): New definition.
	(cp_parser_omp_unroll): New function for parsing "omp unroll"
	loops that are not associated with another directive.

	(cp_parser_omp_construct): Handle PRAGMA_OMP_UNROLL.
	(cp_parser_pragma): Handle PRAGMA_OMP_UNROLL.
	* pt.cc (tsubst_omp_clauses): Handle
	OMP_CLAUSE_UNROLL_PARTIAL, OMP_CLAUSE_UNROLL_FULL, and
	OMP_CLAUSE_UNROLL_NONE.
	(tsubst_expr): Handle OMP_UNROLL.
	* semantics.cc (finish_omp_clauses): Handle
	OMP_CLAUSE_UNROLL_FULL, OMP_CLAUSE_UNROLL_PARTIAL,
	and OMP_CLAUSE_UNROLL_NONE.

libgomp/ChangeLog:

	* testsuite/libgomp.c++/loop-transforms/unroll-1.C: New test.
	* testsuite/libgomp.c++/loop-transforms/unroll-2.C: New test.
	* testsuite/libgomp.c-c++-common/loop-transforms/unroll-1.c: New test.

gcc/testsuite/ChangeLog:

	* c-c++-common/gomp/loop-transforms/unroll-1.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-2.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-3.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-4.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-5.c: New test.
	* c-c++-common/gomp/loop-transforms/unroll-6.c: New test.
	* g++.dg/gomp/loop-transforms/unroll-1.C: New test.
	* g++.dg/gomp/loop-transforms/unroll-2.C: New test.
	* g++.dg/gomp/loop-transforms/unroll-3.C: New test.

5 files changed, 19 insertions, 4 deletions

diff --git a/gcc/c-family/ChangeLog.omp b/gcc/c-family/ChangeLog.omp
index 8690eb06694..ac8f6e61a5d 100644
--- a/gcc/c-family/ChangeLog.omp
+++ b/gcc/c-family/ChangeLog.omp
@@ -1,3 +1,13 @@
+2023-03-24  Frederik Harwath  <frederik@codesourcery.com>
+
+	* c-gimplify.cc (c_genericize_control_stmt): Handle OMP_UNROLL.
+	* c-omp.cc: Add "unroll" to omp_directives[].
+	* c-pragma.cc: Add "unroll" to omp_pragmas_simd[].
+	* c-pragma.h (enum pragma_kind): Add PRAGMA_OMP_UNROLL to
+	pragma_kind and adjust PRAGMA_OMP__LAST_.
+	(enum pragma_omp_clause): Add PRAGMA_OMP_CLAUSE_FULL and
+	PRAGMA_OMP_CLAUSE_PARTIAL.
+
 2022-04-15  Kwok Cheung Yeung  <kcy@codesourcery.com>
 
 	gcc/c-family/
diff --git a/gcc/c-family/c-gimplify.cc b/gcc/c-family/c-gimplify.cc
index 67657e0da72..25e6587e3a1 100644
--- a/gcc/c-family/c-gimplify.cc
+++ b/gcc/c-family/c-gimplify.cc
@@ -526,6 +526,7 @@ c_genericize_control_stmt (tree *stmt_p, int *walk_subtrees, void *data,
     case OMP_DISTRIBUTE:
     case OMP_LOOP:
     case OMP_TASKLOOP:
+    case OMP_LOOP_TRANS:
     case OACC_LOOP:
       genericize_omp_for_stmt (stmt_p, walk_subtrees, data, func, lh);
       break;
diff --git a/gcc/c-family/c-omp.cc b/gcc/c-family/c-omp.cc
index 7eb3b3f1721..f0d13f62822 100644
--- a/gcc/c-family/c-omp.cc
+++ b/gcc/c-family/c-omp.cc
@@ -4010,9 +4010,9 @@ const struct c_omp_directive c_omp_directives[] = {
   { "teams", nullptr, nullptr, PRAGMA_OMP_TEAMS,
     C_OMP_DIR_CONSTRUCT, true },
   { "threadprivate", nullptr, nullptr, PRAGMA_OMP_THREADPRIVATE,
-    C_OMP_DIR_DECLARATIVE, false }
-  /* { "unroll", nullptr, nullptr, PRAGMA_OMP_UNROLL,
-    C_OMP_DIR_CONSTRUCT, false },  */
+    C_OMP_DIR_DECLARATIVE, false },
+ { "unroll", nullptr, nullptr, PRAGMA_OMP_UNROLL,
+    C_OMP_DIR_CONSTRUCT, false },
 };
 
 /* Find (non-combined/composite) OpenMP directive (if any) which starts
diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc
index af4965b31cd..1ab8e51885d 100644
--- a/gcc/c-family/c-pragma.cc
+++ b/gcc/c-family/c-pragma.cc
@@ -1594,6 +1594,7 @@ static const struct omp_pragma_def omp_pragmas_simd[] = {
   { "target", PRAGMA_OMP_TARGET },
   { "taskloop", PRAGMA_OMP_TASKLOOP },
   { "teams", PRAGMA_OMP_TEAMS },
+  { "unroll", PRAGMA_OMP_UNROLL },
 };
 
 void
diff --git a/gcc/c-family/c-pragma.h b/gcc/c-family/c-pragma.h
index 4ea043d009f..4a7df86bc7a 100644
--- a/gcc/c-family/c-pragma.h
+++ b/gcc/c-family/c-pragma.h
@@ -82,8 +82,9 @@ enum pragma_kind {
   PRAGMA_OMP_TASKYIELD,
   PRAGMA_OMP_THREADPRIVATE,
   PRAGMA_OMP_TEAMS,
+  PRAGMA_OMP_UNROLL,
   /* PRAGMA_OMP__LAST_ should be equal to the last PRAGMA_OMP_* code.  */
-  PRAGMA_OMP__LAST_ = PRAGMA_OMP_TEAMS,
+  PRAGMA_OMP__LAST_ = PRAGMA_OMP_UNROLL,
 
   PRAGMA_GCC_PCH_PREPROCESS,
   PRAGMA_IVDEP,
@@ -119,6 +120,7 @@ enum pragma_omp_clause {
   PRAGMA_OMP_CLAUSE_FIRSTPRIVATE,
   PRAGMA_OMP_CLAUSE_FOR,
   PRAGMA_OMP_CLAUSE_FROM,
+  PRAGMA_OMP_CLAUSE_FULL,
   PRAGMA_OMP_CLAUSE_GRAINSIZE,
   PRAGMA_OMP_CLAUSE_HAS_DEVICE_ADDR,
   PRAGMA_OMP_CLAUSE_HINT,
@@ -141,6 +143,7 @@ enum pragma_omp_clause {
   PRAGMA_OMP_CLAUSE_ORDER,
   PRAGMA_OMP_CLAUSE_ORDERED,
   PRAGMA_OMP_CLAUSE_PARALLEL,
+  PRAGMA_OMP_CLAUSE_PARTIAL,
   PRAGMA_OMP_CLAUSE_PRIORITY,
   PRAGMA_OMP_CLAUSE_PRIVATE,
   PRAGMA_OMP_CLAUSE_PROC_BIND,