From a6706e1b674bedfc375be00660671d4d0528a599 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Sun, 16 Mar 2014 11:58:47 +0100
Subject: [PATCH] add pet_context_clear_writes_in_{expr,tree}

We will need these functions in the next commit.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 context.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 context.h |  7 +++++++
 2 files changed, 54 insertions(+)

diff --git a/context.c b/context.c
index afa8c1d..723f76f 100644
--- a/context.c
+++ b/context.c
@@ -35,6 +35,7 @@
 #include <isl/aff.h>
 
 #include "context.h"
+#include "expr.h"
 
 /* A pet_context represents the context in which a pet_expr
  * in converted to an affine expression.
@@ -378,6 +379,52 @@ __isl_give pet_context *pet_context_set_allow_nested(__isl_take pet_context *pc,
 	return pc;
 }
 
+/* If the access expression "expr" writes to a (non-virtual) scalar,
+ * then mark the scalar as having an unknown value in "pc".
+ */
+static int clear_write(__isl_keep pet_expr *expr, void *user)
+{
+	isl_id *id;
+	pet_context **pc = (pet_context **) user;
+
+	if (!pet_expr_access_is_write(expr))
+		return 0;
+	if (!pet_expr_is_scalar_access(expr))
+		return 0;
+
+	id = pet_expr_access_get_id(expr);
+	if (isl_id_get_user(id))
+		*pc = pet_context_mark_assigned(*pc, id);
+	else
+		isl_id_free(id);
+
+	return 0;
+}
+
+/* Look for any writes to scalar variables in "expr" and
+ * mark them as having an unknown value in "pc".
+ */
+__isl_give pet_context *pet_context_clear_writes_in_expr(
+	__isl_take pet_context *pc, __isl_keep pet_expr *expr)
+{
+	if (pet_expr_foreach_access_expr(expr, &clear_write, &pc) < 0)
+		pc = pet_context_free(pc);
+
+	return pc;
+}
+
+/* Look for any writes to scalar variables in "tree" and
+ * mark them as having an unknown value in "pc".
+ */
+__isl_give pet_context *pet_context_clear_writes_in_tree(
+	__isl_take pet_context *pc, __isl_keep pet_tree *tree)
+{
+	if (pet_tree_foreach_access_expr(tree, &clear_write, &pc) < 0)
+		pc = pet_context_free(pc);
+
+	return pc;
+}
+
 void pet_context_dump(__isl_keep pet_context *pc)
 {
 	if (!pc)
diff --git a/context.h b/context.h
index 20e7c8c..02d7895 100644
--- a/context.h
+++ b/context.h
@@ -4,6 +4,8 @@
 #include <isl/space.h>
 #include <isl/id_to_pw_aff.h>
 
+#include <pet.h>
+
 #if defined(__cplusplus)
 extern "C" {
 #endif
@@ -36,6 +38,11 @@ __isl_give pet_context *pet_context_set_allow_nested(__isl_take pet_context *pc,
 	int allow_nested);
 int pet_context_allow_nesting(__isl_keep pet_context *pc);
 
+__isl_give pet_context *pet_context_clear_writes_in_expr(
+	__isl_take pet_context *pc, __isl_keep pet_expr *expr);
+__isl_give pet_context *pet_context_clear_writes_in_tree(
+	__isl_take pet_context *pc, __isl_keep pet_tree *tree);
+
 void pet_context_dump(__isl_keep pet_context *pc);
 
 #if defined(__cplusplus)
-- 
2.11.4.GIT