openmp: Fix up handling of reduction clause on constructs combined with target [PR99928]

The reduction clause should be copied as map (tofrom: ) to combined target if
present, but as we need different handling of array sections between map and reduction,
doing that during gimplification would be harder.

So, this patch adds them during splitting, and similarly to firstprivate adds them
with a new flag that they should be just ignored/removed if an explicit map clause
of the same list item is present.

The exact rules are to be decided in https://github.com/OpenMP/spec/issues/2766
so this patch just implements something that is IMHO reasonable and exact detailed
testcases for the cornercases will follow once it is clarified.

2021-05-28  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/99928
gcc/
	* tree.h (OMP_CLAUSE_MAP_IMPLICIT): Define.
gcc/c-family/
	* c-omp.c (c_omp_split_clauses): For reduction clause if combined with
	target add a map tofrom clause with OMP_CLAUSE_MAP_IMPLICIT.
gcc/c/
	* c-typeck.c (handle_omp_array_sections): Copy OMP_CLAUSE_MAP_IMPLICIT.
	(c_finish_omp_clauses): Move not just OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT
	marked clauses last, but also OMP_CLAUSE_MAP_IMPLICIT.  Add
	map_firstprivate_head bitmap, set it for GOMP_MAP_FIRSTPRIVATE_POINTER
	maps and silently remove OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT if it is
	present too.  For OMP_CLAUSE_MAP_IMPLICIT silently remove the clause
	if present in map_head, map_field_head or map_firstprivate_head
	bitmaps.
gcc/cp/
	* semantics.c (handle_omp_array_sections): Copy
	OMP_CLAUSE_MAP_IMPLICIT.
	(finish_omp_clauses): Move not just OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT
	marked clauses last, but also OMP_CLAUSE_MAP_IMPLICIT.  Add
	map_firstprivate_head bitmap, set it for GOMP_MAP_FIRSTPRIVATE_POINTER
	maps and silently remove OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT if it is
	present too.  For OMP_CLAUSE_MAP_IMPLICIT silently remove the clause
	if present in map_head, map_field_head or map_firstprivate_head
	bitmaps.
gcc/testsuite/
	* c-c++-common/gomp/pr99928-8.c: Remove all xfails.
	* c-c++-common/gomp/pr99928-9.c: Likewise.
	* c-c++-common/gomp/pr99928-10.c: Likewise.
	* c-c++-common/gomp/pr99928-16.c: New test.

1 files changed, 52 insertions, 13 deletions

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 6fafd06..fe370a2 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -5548,6 +5548,7 @@ handle_omp_array_sections (tree c, enum c_omp_region_type ort)
 	    }
 	  else
 	    OMP_CLAUSE_SET_MAP_KIND (c2, GOMP_MAP_FIRSTPRIVATE_POINTER);
+	  OMP_CLAUSE_MAP_IMPLICIT (c2) = OMP_CLAUSE_MAP_IMPLICIT (c);
 	  if (OMP_CLAUSE_MAP_KIND (c2) != GOMP_MAP_FIRSTPRIVATE_POINTER
 	      && !cxx_mark_addressable (t))
 	    return false;
@@ -5574,6 +5575,7 @@ handle_omp_array_sections (tree c, enum c_omp_region_type ort)
 	      tree c3 = build_omp_clause (OMP_CLAUSE_LOCATION (c),
 					  OMP_CLAUSE_MAP);
 	      OMP_CLAUSE_SET_MAP_KIND (c3, OMP_CLAUSE_MAP_KIND (c2));
+	      OMP_CLAUSE_MAP_IMPLICIT (c2) = OMP_CLAUSE_MAP_IMPLICIT (c);
 	      OMP_CLAUSE_DECL (c3) = ptr;
 	      if (OMP_CLAUSE_MAP_KIND (c2) == GOMP_MAP_ALWAYS_POINTER
 		  || OMP_CLAUSE_MAP_KIND (c2) == GOMP_MAP_ATTACH_DETACH)
@@ -6510,7 +6512,8 @@ tree
 finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 {
   bitmap_head generic_head, firstprivate_head, lastprivate_head;
-  bitmap_head aligned_head, map_head, map_field_head, oacc_reduction_head;
+  bitmap_head aligned_head, map_head, map_field_head, map_firstprivate_head;
+  bitmap_head oacc_reduction_head;
   tree c, t, *pc;
   tree safelen = NULL_TREE;
   bool branch_seen = false;
@@ -6527,7 +6530,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
   bool allocate_seen = false;
   tree detach_seen = NULL_TREE;
   bool mergeable_seen = false;
-  bool firstprivate_implicit_moved = false;
+  bool implicit_moved = false;
 
   bitmap_obstack_initialize (NULL);
   bitmap_initialize (&generic_head, &bitmap_default_obstack);
@@ -6537,6 +6540,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
   /* If ort == C_ORT_OMP_DECLARE_SIMD used as uniform_head instead.  */
   bitmap_initialize (&map_head, &bitmap_default_obstack);
   bitmap_initialize (&map_field_head, &bitmap_default_obstack);
+  bitmap_initialize (&map_firstprivate_head, &bitmap_default_obstack);
   /* If ort == C_ORT_OMP used as nontemporal_head or use_device_xxx_head
      instead.  */
   bitmap_initialize (&oacc_reduction_head, &bitmap_default_obstack);
@@ -6852,28 +6856,36 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	  break;
 
 	case OMP_CLAUSE_FIRSTPRIVATE:
-	  if (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (c)
-	      && !firstprivate_implicit_moved)
+	  if (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (c) && !implicit_moved)
 	    {
-	      firstprivate_implicit_moved = true;
-	      /* Move firstprivate clauses with
-		 OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT set to the end of
+	    move_implicit:
+	      implicit_moved = true;
+	      /* Move firstprivate and map clauses with
+		 OMP_CLAUSE_{FIRSTPRIVATE,MAP}_IMPLICIT set to the end of
 		 clauses chain.  */
-	      tree cl = NULL, *pc1 = pc, *pc2 = &cl;
+	      tree cl1 = NULL_TREE, cl2 = NULL_TREE;
+	      tree *pc1 = pc, *pc2 = &cl1, *pc3 = &cl2;
 	      while (*pc1)
 		if (OMP_CLAUSE_CODE (*pc1) == OMP_CLAUSE_FIRSTPRIVATE
 		    && OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (*pc1))
 		  {
+		    *pc3 = *pc1;
+		    pc3 = &OMP_CLAUSE_CHAIN (*pc3);
+		    *pc1 = OMP_CLAUSE_CHAIN (*pc1);
+		  }
+		else if (OMP_CLAUSE_CODE (*pc1) == OMP_CLAUSE_MAP
+			 && OMP_CLAUSE_MAP_IMPLICIT (*pc1))
+		  {
 		    *pc2 = *pc1;
 		    pc2 = &OMP_CLAUSE_CHAIN (*pc2);
 		    *pc1 = OMP_CLAUSE_CHAIN (*pc1);
 		  }
 		else
 		  pc1 = &OMP_CLAUSE_CHAIN (*pc1);
-	      *pc2 = NULL;
-	      *pc1 = cl;
-	      if (pc1 != pc)
-		continue;
+	      *pc3 = NULL;
+	      *pc2 = cl2;
+	      *pc1 = cl1;
+	      continue;
 	    }
 	  t = omp_clause_decl_field (OMP_CLAUSE_DECL (c));
 	  if (t)
@@ -6904,6 +6916,10 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 			  t);
 	      remove = true;
 	    }
+	  else if (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (c)
+		   && !OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT_TARGET (c)
+		   && bitmap_bit_p (&map_firstprivate_head, DECL_UID (t)))
+	    remove = true;
 	  else if (bitmap_bit_p (&generic_head, DECL_UID (t))
 		   || bitmap_bit_p (&firstprivate_head, DECL_UID (t)))
 	    {
@@ -7620,6 +7636,9 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	  break;
 
 	case OMP_CLAUSE_MAP:
+	  if (OMP_CLAUSE_MAP_IMPLICIT (c) && !implicit_moved)
+	    goto move_implicit;
+	  /* FALLTHRU */
 	case OMP_CLAUSE_TO:
 	case OMP_CLAUSE_FROM:
 	case OMP_CLAUSE__CACHE_:
@@ -7651,6 +7670,16 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 			t = TREE_OPERAND (t, 0);
 		      if (REFERENCE_REF_P (t))
 			t = TREE_OPERAND (t, 0);
+		      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
+			  && OMP_CLAUSE_MAP_IMPLICIT (c)
+			  && (bitmap_bit_p (&map_head, DECL_UID (t))
+			      || bitmap_bit_p (&map_field_head, DECL_UID (t))
+			      || bitmap_bit_p (&map_firstprivate_head,
+					       DECL_UID (t))))
+			{
+			  remove = true;
+			  break;
+			}
 		      if (bitmap_bit_p (&map_field_head, DECL_UID (t)))
 			break;
 		      if (bitmap_bit_p (&map_head, DECL_UID (t)))
@@ -7832,6 +7861,13 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	      remove = true;
 	    }
 	  else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
+		   && OMP_CLAUSE_MAP_IMPLICIT (c)
+		   && (bitmap_bit_p (&map_head, DECL_UID (t))
+		       || bitmap_bit_p (&map_field_head, DECL_UID (t))
+		       || bitmap_bit_p (&map_firstprivate_head,
+					DECL_UID (t))))
+	    remove = true;
+	  else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_MAP
 		   && OMP_CLAUSE_MAP_KIND (c) == GOMP_MAP_FIRSTPRIVATE_POINTER)
 	    {
 	      if (bitmap_bit_p (&generic_head, DECL_UID (t))
@@ -7852,7 +7888,10 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		  remove = true;
 		}
 	      else
-		bitmap_set_bit (&generic_head, DECL_UID (t));
+		{
+		  bitmap_set_bit (&generic_head, DECL_UID (t));
+		  bitmap_set_bit (&map_firstprivate_head, DECL_UID (t));
+		}
 	    }
 	  else if (bitmap_bit_p (&map_head, DECL_UID (t))
 		   && !bitmap_bit_p (&map_field_head, DECL_UID (t)))