Re: [Fortran, Patch] Memory sync after coarray image control statements and assignment

[Tobias Burnus]

I wrote:
> I wonder whether using
>
> __asm__ __volatile__ ("":::"memory");
>
> would be sufficient as it has a way lower overhead than 
> __sync_synchronize().

Namely, something like the attached patch.

Regarding the original patch submission: Is there a reason that you didn't
include the test case of Deepak from 
https://gcc.gnu.org/ml/fortran/2015-04/msg00062.html
It should work as -fcoarray=lib -lcaf_single "dg-do run" test.

Tobias

 trans-intrinsic.c |   18 ++++++++++++++++++
 trans-stmt.c      |   29 +++++++++++++++++++++++++++++
 trans.c           |   16 ++++++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/gcc/fortran/trans-intrinsic.c b/gcc/fortran/trans-intrinsic.c
index 21efe44..04ba3ea 100644
--- a/gcc/fortran/trans-intrinsic.c
+++ b/gcc/fortran/trans-intrinsic.c
@@ -1222,6 +1222,15 @@ gfc_conv_intrinsic_caf_get (gfc_se *se, gfc_expr *expr, tree lhs, tree lhs_kind,
   se->expr = res_var;
   if (array_expr->ts.type == BT_CHARACTER)
     se->string_length = argse.string_length;
+
+  /* It guarantees memory consistency within the same segment */
+  tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+  tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+		    gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+		    tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+  ASM_VOLATILE_P (tmp) = 1;
+  gfc_add_expr_to_block (&se->pre, tmp);
+
 }
 
 
@@ -1390,6 +1399,15 @@ conv_caf_send (gfc_code *code) {
   gfc_add_expr_to_block (&block, tmp);
   gfc_add_block_to_block (&block, &lhs_se.post);
   gfc_add_block_to_block (&block, &rhs_se.post);
+
+  /* It guarantees memory consistency within the same segment */
+  tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+  tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+		    gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+		    tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+  ASM_VOLATILE_P (tmp) = 1;
+  gfc_add_expr_to_block (&block, tmp);
+
   return gfc_finish_block (&block);
 }
 
diff --git a/gcc/fortran/trans-stmt.c b/gcc/fortran/trans-stmt.c
index 3df483a..b7e1faa 100644
--- a/gcc/fortran/trans-stmt.c
+++ b/gcc/fortran/trans-stmt.c
@@ -818,6 +818,15 @@ gfc_trans_lock_unlock (gfc_code *code, gfc_exec_op op)
 				   errmsg, errmsg_len);
       gfc_add_expr_to_block (&se.pre, tmp);
 
+      /* It guarantees memory consistency within the same segment */
+      tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+      tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+			gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+			tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+      ASM_VOLATILE_P (tmp) = 1;
+
+      gfc_add_expr_to_block (&se.pre, tmp);
+
       if (stat2 != NULL_TREE)
 	gfc_add_modify (&se.pre, stat2,
 			fold_convert (TREE_TYPE (stat2), stat));
@@ -995,6 +1004,14 @@ gfc_trans_event_post_wait (gfc_code *code, gfc_exec_op op)
 			       errmsg, errmsg_len);
   gfc_add_expr_to_block (&se.pre, tmp);
 
+  /* It guarantees memory consistency within the same segment */
+  tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+  tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+		    gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+		    tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+  ASM_VOLATILE_P (tmp) = 1;
+  gfc_add_expr_to_block (&se.pre, tmp);
+
   if (stat2 != NULL_TREE)
     gfc_add_modify (&se.pre, stat2, fold_convert (TREE_TYPE (stat2), stat));
 
@@ -1080,6 +1097,18 @@ gfc_trans_sync (gfc_code *code, gfc_exec_op type)
 			       fold_convert (integer_type_node, images));
     }
 
+  /* Per F2008, 8.5.1, a SYNC MEMORY is implied by calling the
+     image control statements SYNC IMAGES and SYNC ALL.  */
+  if (flag_coarray == GFC_FCOARRAY_LIB)
+    {
+      tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+      tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+			gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+			tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+      ASM_VOLATILE_P (tmp) = 1;
+      gfc_add_expr_to_block (&se.pre, tmp);
+    }
+
   if (flag_coarray != GFC_FCOARRAY_LIB)
     {
       /* Set STAT to zero.  */
diff --git a/gcc/fortran/trans.c b/gcc/fortran/trans.c
index 001db41..1993743 100644
--- a/gcc/fortran/trans.c
+++ b/gcc/fortran/trans.c
@@ -746,6 +746,14 @@ gfc_allocate_using_lib (stmtblock_t * block, tree pointer, tree size,
 			 TREE_TYPE (pointer), pointer,
 			 fold_convert ( TREE_TYPE (pointer), tmp));
   gfc_add_expr_to_block (block, tmp);
+
+  /* It guarantees memory consistency within the same segment */
+  tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+  tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+		    gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+		    tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+  ASM_VOLATILE_P (tmp) = 1;
+  gfc_add_expr_to_block (block, tmp);
 }
 
 
@@ -1356,6 +1364,14 @@ gfc_deallocate_with_status (tree pointer, tree status, tree errmsg,
 	     token, pstat, errmsg, errlen);
       gfc_add_expr_to_block (&non_null, tmp);
 
+      /* It guarantees memory consistency within the same segment */
+      tmp = gfc_build_string_const (strlen ("memory")+1, "memory"),
+      tmp = build5_loc (input_location, ASM_EXPR, void_type_node,
+			gfc_build_string_const (1, ""), NULL_TREE, NULL_TREE,
+			tree_cons (NULL_TREE, tmp, NULL_TREE), NULL_TREE);
+      ASM_VOLATILE_P (tmp) = 1;
+      gfc_add_expr_to_block (&non_null, tmp);
+
       if (status != NULL_TREE)
 	{
 	  tree stat = build_fold_indirect_ref_loc (input_location, status);