[OpenMP] Fix mapping of artificial variables (PR94874)

gcc/c-family/ChangeLog:

	* c-common.h (c_omp_predetermined_mapping): Declare.
	* c-omp.c (c_omp_predetermined_mapping): New.

gcc/c/ChangeLog:

	* c-objc-common.h (LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Redefine.

gcc/cp/ChangeLog:

	* cp-gimplify.c (cxx_omp_predetermined_mapping): New.
	* cp-objcp-common.h (LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Redfine.
	* cp-tree.h (cxx_omp_predetermined_mapping): Declare.

gcc/fortran/ChangeLog:

	* f95-lang.c (LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Redefine.
	* trans-openmp.c (gfc_omp_predetermined_mapping): New.
	* trans.h (gfc_omp_predetermined_mapping): Declare.

gcc/ChangeLog:

	* gimplify.c (omp_notice_variable): Use new hook.
	* langhooks-def.h (lhd_omp_predetermined_mapping): Declare.
	(LANG_HOOKS_OMP_PREDETERMINED_MAPPING): Define
	(LANG_HOOKS_DECLS): Add it.
	* langhooks.c (lhd_omp_predetermined_sharing): Remove bogus unused attr.
	(lhd_omp_predetermined_mapping): New.
	* langhooks.h (struct lang_hooks_for_decls): Add new hook.

gcc/testsuite/ChangeLog
2020-06-03  Thomas Schwinge  <thomas@codesourcery.com>
	    Tobias Burnus  <tobias@codesourcery.com>

	PR middle-end/94874
	* c-c++-common/gomp/pr94874.c: New.

14 files changed, 134 insertions, 5 deletions

diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index 7c1a6370aae..c74b23db05c 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1206,6 +1206,7 @@ extern tree c_omp_declare_simd_clauses_to_numbers (tree, tree);
 extern void c_omp_declare_simd_clauses_to_decls (tree, tree);
 extern bool c_omp_predefined_variable (tree);
 extern enum omp_clause_default_kind c_omp_predetermined_sharing (tree);
+extern enum omp_clause_defaultmap_kind c_omp_predetermined_mapping (tree);
 extern tree c_omp_check_context_selector (location_t, tree);
 extern void c_omp_mark_declare_variant (location_t, tree, tree);
 extern const char *c_omp_map_clause_name (tree, bool);
diff --git a/gcc/c-family/c-omp.c b/gcc/c-family/c-omp.c
index 51c18a4ba08..6f8fba350ed 100644
--- a/gcc/c-family/c-omp.c
+++ b/gcc/c-family/c-omp.c
@@ -2104,7 +2104,8 @@ c_omp_predefined_variable (tree decl)
   return false;
 }
 
-/* True if OpenMP sharing attribute of DECL is predetermined.  */
+/* OMP_CLAUSE_DEFAULT_UNSPECIFIED unless OpenMP sharing attribute of DECL
+   is predetermined.  */
 
 enum omp_clause_default_kind
 c_omp_predetermined_sharing (tree decl)
@@ -2123,6 +2124,27 @@ c_omp_predetermined_sharing (tree decl)
   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 }
 
+/* OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED unless OpenMP mapping attribute
+   of DECL is predetermined.  */
+
+enum omp_clause_defaultmap_kind
+c_omp_predetermined_mapping (tree decl)
+{
+  /* Predetermine artificial variables holding integral values, those
+     are usually result of gimplify_one_sizepos or SAVE_EXPR
+     gimplification.  */
+  if (VAR_P (decl)
+      && DECL_ARTIFICIAL (decl)
+      && INTEGRAL_TYPE_P (TREE_TYPE (decl)))
+    return OMP_CLAUSE_DEFAULTMAP_FIRSTPRIVATE;
+
+  if (c_omp_predefined_variable (decl))
+    return OMP_CLAUSE_DEFAULTMAP_TO;
+
+  return OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED;
+}
+
+
 /* Diagnose errors in an OpenMP context selector, return CTX if
    it is correct or error_mark_node otherwise.  */
 
diff --git a/gcc/c/c-objc-common.h b/gcc/c/c-objc-common.h
index bfdb2797ff4..5471fc7e355 100644
--- a/gcc/c/c-objc-common.h
+++ b/gcc/c/c-objc-common.h
@@ -107,6 +107,9 @@ along with GCC; see the file COPYING3.  If not see
 #undef LANG_HOOKS_OMP_PREDETERMINED_SHARING
 #define LANG_HOOKS_OMP_PREDETERMINED_SHARING c_omp_predetermined_sharing
 
+#undef LANG_HOOKS_OMP_PREDETERMINED_MAPPING
+#define LANG_HOOKS_OMP_PREDETERMINED_MAPPING c_omp_predetermined_mapping
+
 #undef LANG_HOOKS_OMP_CLAUSE_COPY_CTOR
 #define LANG_HOOKS_OMP_CLAUSE_COPY_CTOR c_omp_clause_copy_ctor
 
diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index d6723e44ec4..6c29be9d836 100644
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -2267,7 +2267,8 @@ cxx_omp_const_qual_no_mutable (tree decl)
   return false;
 }
 
-/* True if OpenMP sharing attribute of DECL is predetermined.  */
+/* OMP_CLAUSE_DEFAULT_UNSPECIFIED unless OpenMP sharing attribute
+   of DECL is predetermined.  */
 
 enum omp_clause_default_kind
 cxx_omp_predetermined_sharing_1 (tree decl)
@@ -2321,6 +2322,25 @@ cxx_omp_predetermined_sharing (tree decl)
   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 }
 
+enum omp_clause_defaultmap_kind
+cxx_omp_predetermined_mapping (tree decl)
+{
+  /* Predetermine artificial variables holding integral values, those
+     are usually result of gimplify_one_sizepos or SAVE_EXPR
+     gimplification.  */
+  if (VAR_P (decl)
+      && DECL_ARTIFICIAL (decl)
+      && INTEGRAL_TYPE_P (TREE_TYPE (decl))
+      && !(DECL_LANG_SPECIFIC (decl)
+	   && DECL_OMP_PRIVATIZED_MEMBER (decl)))
+    return OMP_CLAUSE_DEFAULTMAP_FIRSTPRIVATE;
+
+  if (c_omp_predefined_variable (decl))
+    return OMP_CLAUSE_DEFAULTMAP_TO;
+
+  return OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED;
+}
+
 /* Finalize an implicitly determined clause.  */
 
 void
diff --git a/gcc/cp/cp-objcp-common.h b/gcc/cp/cp-objcp-common.h
index ff802dc3b41..de8d606fe2c 100644
--- a/gcc/cp/cp-objcp-common.h
+++ b/gcc/cp/cp-objcp-common.h
@@ -162,6 +162,8 @@ extern tree cxx_simulate_enum_decl (location_t, const char *,
 
 #undef LANG_HOOKS_OMP_PREDETERMINED_SHARING
 #define LANG_HOOKS_OMP_PREDETERMINED_SHARING cxx_omp_predetermined_sharing
+#undef LANG_HOOKS_OMP_PREDETERMINED_MAPPING
+#define LANG_HOOKS_OMP_PREDETERMINED_MAPPING cxx_omp_predetermined_mapping
 #undef LANG_HOOKS_OMP_CLAUSE_DEFAULT_CTOR
 #define LANG_HOOKS_OMP_CLAUSE_DEFAULT_CTOR cxx_omp_clause_default_ctor
 #undef LANG_HOOKS_OMP_CLAUSE_COPY_CTOR
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index db125a3a1db..1775b0a4327 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7781,6 +7781,7 @@ extern void cp_genericize			(tree);
 extern bool cxx_omp_const_qual_no_mutable	(tree);
 extern enum omp_clause_default_kind cxx_omp_predetermined_sharing_1 (tree);
 extern enum omp_clause_default_kind cxx_omp_predetermined_sharing (tree);
+extern enum omp_clause_defaultmap_kind cxx_omp_predetermined_mapping (tree);
 extern tree cxx_omp_clause_default_ctor		(tree, tree, tree);
 extern tree cxx_omp_clause_copy_ctor		(tree, tree, tree);
 extern tree cxx_omp_clause_assign_op		(tree, tree, tree);
diff --git a/gcc/fortran/f95-lang.c b/gcc/fortran/f95-lang.c
index 44ebe3e294d..da8c35f47b0 100644
--- a/gcc/fortran/f95-lang.c
+++ b/gcc/fortran/f95-lang.c
@@ -118,6 +118,7 @@ static const struct attribute_spec gfc_attribute_table[] =
 #undef LANG_HOOKS_OMP_CHECK_OPTIONAL_ARGUMENT
 #undef LANG_HOOKS_OMP_PRIVATIZE_BY_REFERENCE
 #undef LANG_HOOKS_OMP_PREDETERMINED_SHARING
+#undef LANG_HOOKS_OMP_PREDETERMINED_MAPPING
 #undef LANG_HOOKS_OMP_REPORT_DECL
 #undef LANG_HOOKS_OMP_CLAUSE_DEFAULT_CTOR
 #undef LANG_HOOKS_OMP_CLAUSE_COPY_CTOR
@@ -153,6 +154,7 @@ static const struct attribute_spec gfc_attribute_table[] =
 #define LANG_HOOKS_OMP_CHECK_OPTIONAL_ARGUMENT	gfc_omp_check_optional_argument
 #define LANG_HOOKS_OMP_PRIVATIZE_BY_REFERENCE	gfc_omp_privatize_by_reference
 #define LANG_HOOKS_OMP_PREDETERMINED_SHARING	gfc_omp_predetermined_sharing
+#define LANG_HOOKS_OMP_PREDETERMINED_MAPPING	gfc_omp_predetermined_mapping
 #define LANG_HOOKS_OMP_REPORT_DECL		gfc_omp_report_decl
 #define LANG_HOOKS_OMP_CLAUSE_DEFAULT_CTOR	gfc_omp_clause_default_ctor
 #define LANG_HOOKS_OMP_CLAUSE_COPY_CTOR		gfc_omp_clause_copy_ctor
diff --git a/gcc/fortran/trans-openmp.c b/gcc/fortran/trans-openmp.c
index e27ce41b7ce..7e2f6256c43 100644
--- a/gcc/fortran/trans-openmp.c
+++ b/gcc/fortran/trans-openmp.c
@@ -207,7 +207,8 @@ gfc_omp_privatize_by_reference (const_tree decl)
   return false;
 }
 
-/* True if OpenMP sharing attribute of DECL is predetermined.  */
+/* OMP_CLAUSE_DEFAULT_UNSPECIFIED unless OpenMP sharing attribute
+   of DECL is predetermined.  */
 
 enum omp_clause_default_kind
 gfc_omp_predetermined_sharing (tree decl)
@@ -278,6 +279,28 @@ gfc_omp_predetermined_sharing (tree decl)
   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 }
 
+
+/* OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED unless OpenMP mapping attribute
+   of DECL is predetermined.  */
+
+enum omp_clause_defaultmap_kind
+gfc_omp_predetermined_mapping (tree decl)
+{
+  if (DECL_ARTIFICIAL (decl)
+      && ! GFC_DECL_RESULT (decl)
+      && ! (DECL_LANG_SPECIFIC (decl)
+	    && GFC_DECL_SAVED_DESCRIPTOR (decl)))
+    return OMP_CLAUSE_DEFAULTMAP_TO;
+
+  /* These are either array or derived parameters, or vtables.  */
+  if (VAR_P (decl) && TREE_READONLY (decl)
+      && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)))
+    return OMP_CLAUSE_DEFAULTMAP_TO;
+
+  return OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED;
+}
+
+
 /* Return decl that should be used when reporting DEFAULT(NONE)
    diagnostics.  */
 
diff --git a/gcc/fortran/trans.h b/gcc/fortran/trans.h
index bd96cdf86fc..e126fe92782 100644
--- a/gcc/fortran/trans.h
+++ b/gcc/fortran/trans.h
@@ -803,6 +803,7 @@ tree gfc_omp_check_optional_argument (tree, bool);
 tree gfc_omp_array_data (tree, bool);
 bool gfc_omp_privatize_by_reference (const_tree);
 enum omp_clause_default_kind gfc_omp_predetermined_sharing (tree);
+enum omp_clause_defaultmap_kind gfc_omp_predetermined_mapping (tree);
 tree gfc_omp_report_decl (tree);
 tree gfc_omp_clause_default_ctor (tree, tree, tree);
 tree gfc_omp_clause_copy_ctor (tree, tree, tree);
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 7f00d97baa1..cb08b26dc65 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -7432,6 +7432,7 @@ omp_notice_variable (struct gimplify_omp_ctx *ctx, tree decl, bool in_code)
 	      if (!is_declare_target)
 		{
 		  int gdmk;
+		  enum omp_clause_defaultmap_kind kind;
 		  if (TREE_CODE (TREE_TYPE (decl)) == POINTER_TYPE
 		      || (TREE_CODE (TREE_TYPE (decl)) == REFERENCE_TYPE
 			  && (TREE_CODE (TREE_TYPE (TREE_TYPE (decl)))
@@ -7441,7 +7442,17 @@ omp_notice_variable (struct gimplify_omp_ctx *ctx, tree decl, bool in_code)
 		    gdmk = GDMK_SCALAR;
 		  else
 		    gdmk = GDMK_AGGREGATE;
-		  if (ctx->defaultmap[gdmk] == 0)
+		  kind = lang_hooks.decls.omp_predetermined_mapping (decl);
+		  if (kind != OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED)
+		    {
+		      if (kind == OMP_CLAUSE_DEFAULTMAP_FIRSTPRIVATE)
+			nflags |= GOVD_FIRSTPRIVATE;
+		      else if (kind == OMP_CLAUSE_DEFAULTMAP_TO)
+			nflags |= GOVD_MAP | GOVD_MAP_TO_ONLY;
+		      else
+			gcc_unreachable ();
+		    }
+		  else if (ctx->defaultmap[gdmk] == 0)
 		    {
 		      tree d = lang_hooks.decls.omp_report_decl (decl);
 		      error ("%qE not specified in enclosing %<target%>",
diff --git a/gcc/langhooks-def.h b/gcc/langhooks-def.h
index 82aeb653085..6e4e2cc9367 100644
--- a/gcc/langhooks-def.h
+++ b/gcc/langhooks-def.h
@@ -79,6 +79,7 @@ extern bool lhd_handle_option (size_t, const char *, HOST_WIDE_INT, int,
 /* Declarations for tree gimplification hooks.  */
 extern int lhd_gimplify_expr (tree *, gimple_seq *, gimple_seq *);
 extern enum omp_clause_default_kind lhd_omp_predetermined_sharing (tree);
+extern enum omp_clause_defaultmap_kind lhd_omp_predetermined_mapping (tree);
 extern tree lhd_omp_assignment (tree, tree, tree);
 extern void lhd_omp_finish_clause (tree, gimple_seq *);
 struct gimplify_omp_ctx;
@@ -246,6 +247,7 @@ extern tree lhd_unit_size_without_reusable_padding (tree);
 #define LANG_HOOKS_OMP_CHECK_OPTIONAL_ARGUMENT hook_tree_tree_bool_null
 #define LANG_HOOKS_OMP_PRIVATIZE_BY_REFERENCE hook_bool_const_tree_false
 #define LANG_HOOKS_OMP_PREDETERMINED_SHARING lhd_omp_predetermined_sharing
+#define LANG_HOOKS_OMP_PREDETERMINED_MAPPING lhd_omp_predetermined_mapping
 #define LANG_HOOKS_OMP_REPORT_DECL lhd_pass_through_t
 #define LANG_HOOKS_OMP_DISREGARD_VALUE_EXPR hook_bool_tree_bool_false
 #define LANG_HOOKS_OMP_PRIVATE_DEBUG_CLAUSE hook_bool_tree_bool_false
@@ -274,6 +276,7 @@ extern tree lhd_unit_size_without_reusable_padding (tree);
   LANG_HOOKS_OMP_CHECK_OPTIONAL_ARGUMENT, \
   LANG_HOOKS_OMP_PRIVATIZE_BY_REFERENCE, \
   LANG_HOOKS_OMP_PREDETERMINED_SHARING, \
+  LANG_HOOKS_OMP_PREDETERMINED_MAPPING, \
   LANG_HOOKS_OMP_REPORT_DECL, \
   LANG_HOOKS_OMP_DISREGARD_VALUE_EXPR, \
   LANG_HOOKS_OMP_PRIVATE_DEBUG_CLAUSE, \
diff --git a/gcc/langhooks.c b/gcc/langhooks.c
index 5e3216da631..1cb7cda5b79 100644
--- a/gcc/langhooks.c
+++ b/gcc/langhooks.c
@@ -579,13 +579,24 @@ lhd_expr_to_decl (tree expr, bool *tc ATTRIBUTE_UNUSED, bool *se ATTRIBUTE_UNUSE
    predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 
 enum omp_clause_default_kind
-lhd_omp_predetermined_sharing (tree decl ATTRIBUTE_UNUSED)
+lhd_omp_predetermined_sharing (tree decl)
 {
   if (DECL_ARTIFICIAL (decl))
     return OMP_CLAUSE_DEFAULT_SHARED;
   return OMP_CLAUSE_DEFAULT_UNSPECIFIED;
 }
 
+/* Return sharing kind if OpenMP mapping attribute of DECL is
+   predetermined, OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED otherwise.  */
+
+enum omp_clause_defaultmap_kind
+lhd_omp_predetermined_mapping (tree decl)
+{
+  if (DECL_ARTIFICIAL (decl))
+    return OMP_CLAUSE_DEFAULTMAP_TO;
+  return OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED;
+}
+
 /* Generate code to copy SRC to DST.  */
 
 tree
diff --git a/gcc/langhooks.h b/gcc/langhooks.h
index 83069a9cf7f..2bd5a67cd37 100644
--- a/gcc/langhooks.h
+++ b/gcc/langhooks.h
@@ -252,6 +252,10 @@ struct lang_hooks_for_decls
      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 
+  /* Return mapping kind if OpenMP mapping attribute of DECL is
+     predetermined, OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED otherwise.  */
+  enum omp_clause_defaultmap_kind (*omp_predetermined_mapping) (tree);
+
   /* Return decl that should be reported for DEFAULT(NONE) failure
      diagnostics.  Usually the DECL passed in.  */
   tree (*omp_report_decl) (tree);
diff --git a/gcc/testsuite/c-c++-common/gomp/pr94874.c b/gcc/testsuite/c-c++-common/gomp/pr94874.c
new file mode 100644
index 00000000000..9c67f83a5da
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/pr94874.c
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fdump-tree-gimple" } */
+
+#include <stddef.h>
+
+size_t
+vla (int array_li)
+{
+  float array[array_li];
+  size_t size1, size2;
+
+#pragma omp parallel default(none) shared(size1, array)
+  size1 = sizeof array;
+
+#pragma omp target defaultmap(none) map(from:size2) map(alloc:array)
+  size2 = sizeof array;
+
+  return size1 + size2;
+}
+
+/* { dg-final { scan-tree-dump "omp parallel .*shared\\(array_li\.\[0-9\]\\)" "gimple" } } */
+/* C */
+/* { dg-final { scan-tree-dump "omp target .*private\\(array_li\.\[0-9\]\\)" "gimple" { target { ! c++ } } } } */
+/* C++ */
+/* { dg-final { scan-tree-dump "omp target .*firstprivate\\(array_li\.\[0-9\]\\)" "gimple" { target { c++ } } } } */