From a413bd286f0748af489288fd73675bad00cfac07 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Thu, 22 Aug 2013 15:12:54 +0200
Subject: [PATCH] gpu_array_info: replace read_only by read_only_scalar

The original field only contained meaningful information if
the corresponding array is a scalar, which could be confusing.
The new field is set iff the array is a scalar and it is read-only.

Extract the corresponding check into a separate function
to reduce clutter.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 gpu.c       | 42 ++++++++++++++++++++++++++----------------
 gpu.h       |  4 ++--
 gpu_print.c |  2 +-
 3 files changed, 29 insertions(+), 19 deletions(-)

diff --git a/gpu.c b/gpu.c
index 66b252d..e02c43d 100644
--- a/gpu.c
+++ b/gpu.c
@@ -375,6 +375,30 @@ static __isl_give isl_set *compute_extent(struct pet_array *array,
 	return extent;
 }
 
+/* Is the array "array" being extracted a read-only scalar?
+ *
+ * That is, is "array" a scalar that is never written to.
+ */
+static int is_read_only_scalar(struct gpu_array_info *array,
+	struct gpu_prog *prog)
+{
+	isl_set *space;
+	isl_union_map *write;
+	int empty;
+
+	if (array->n_index != 0)
+		return 0;
+
+	write = isl_union_map_copy(prog->write);
+	space = isl_set_universe(isl_space_copy(array->space));
+	write = isl_union_map_intersect_range(write,
+						isl_union_set_from_set(space));
+	empty = isl_union_map_is_empty(write);
+	isl_union_map_free(write);
+
+	return empty;
+}
+
 /* Compute bounds on the host arrays based on the accessed elements
  * and collect all references to the array.
  *
@@ -415,21 +439,7 @@ static int extract_array_info(__isl_take isl_set *array, void *user)
 	info->type = strdup(pa->element_type);
 	info->size = pa->element_size;
 	info->local = pa->declared && !pa->exposed;
-
-	if (n_index == 0) {
-		isl_set *space;
-		isl_union_map *write;
-		int empty;
-
-		write = isl_union_map_copy(prog->write);
-		space = isl_set_universe(isl_set_get_space(array));
-		write = isl_union_map_intersect_range(write,
-				    isl_union_set_from_set(space));
-		empty = isl_union_map_is_empty(write);
-		isl_union_map_free(write);
-
-		info->read_only = empty;
-	}
+	info->read_only_scalar = is_read_only_scalar(info, prog);
 
 	extent = compute_extent(pa, array);
 	for (i = 0; i < n_index; ++i) {
@@ -515,7 +525,7 @@ int gpu_array_is_scalar(struct gpu_array_info *array)
  */
 int gpu_array_is_read_only_scalar(struct gpu_array_info *array)
 {
-	return gpu_array_is_scalar(array) && array->read_only;
+	return array->read_only_scalar;
 }
 
 /* Internal data structure for extract_size_of_type.
diff --git a/gpu.h b/gpu.h
index 2ac98ec..4789f04 100644
--- a/gpu.h
+++ b/gpu.h
@@ -31,8 +31,8 @@ struct gpu_array_info {
 	int n_group;
 	struct gpu_array_ref_group **groups;
 
-	/* For scalars, is this scalar read-only within the entire program? */
-	int read_only;
+	/* Is this a scalar that is read-only within the entire program? */
+	int read_only_scalar;
 
 	/* Is the array local to the scop? */
 	int local;
diff --git a/gpu_print.c b/gpu_print.c
index dc9a7ab..1af3bcd 100644
--- a/gpu_print.c
+++ b/gpu_print.c
@@ -81,7 +81,7 @@ static __isl_give isl_printer *stmt_print_global_index(
 	isl_ast_expr *index;
 
 	if (gpu_array_is_scalar(array)) {
-		if (!array->read_only)
+		if (!gpu_array_is_read_only_scalar(array))
 			p = isl_printer_print_str(p, "*");
 		p = isl_printer_print_str(p, array->name);
 		return p;
-- 
2.11.4.GIT