From 524176573fb0e5e757c78a65725815feb1f09351 Mon Sep 17 00:00:00 2001
From: Sven Verdoolaege <skimo@kotnet.org>
Date: Mon, 25 Jul 2011 15:09:30 +0200
Subject: [PATCH] accept affine expressions where we expect a condition

In such cases, the condition is taken to be the affine expression being
non-zero.

Reported-by: Sven van Haastregt <svhaastr@liacs.nl>
Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 scan.cc                       | 19 +++++++++++++------
 scan.h                        |  2 ++
 tests/implicit_condition.c    | 11 +++++++++++
 tests/implicit_condition.scop | 21 +++++++++++++++++++++
 4 files changed, 47 insertions(+), 6 deletions(-)
 create mode 100644 tests/implicit_condition.c
 create mode 100644 tests/implicit_condition.scop

diff --git a/scan.cc b/scan.cc
index 56417ec..1b8cda1 100644
--- a/scan.cc
+++ b/scan.cc
@@ -830,7 +830,17 @@ __isl_give isl_set *PetScan::extract_condition(UnaryOperator *expr)
 	}
 }
 
+/* Extract a set of values satisfying the condition "expr != 0".
+ */
+__isl_give isl_set *PetScan::extract_implicit_condition(Expr *expr)
+{
+	return isl_pw_aff_non_zero_set(extract_affine(expr));
+}
+
 /* Extract a set of values satisfying the condition expressed by "expr".
+ *
+ * If the expression doesn't look like a condition, we assume it
+ * is an affine expression and return the condition "expr != 0".
  */
 __isl_give isl_set *PetScan::extract_condition(Expr *expr)
 {
@@ -845,10 +855,8 @@ __isl_give isl_set *PetScan::extract_condition(Expr *expr)
 	if (expr->getStmtClass() == Stmt::UnaryOperatorClass)
 		return extract_condition(cast<UnaryOperator>(expr));
 
-	if (expr->getStmtClass() != Stmt::BinaryOperatorClass) {
-		unsupported(expr);
-		return NULL;
-	}
+	if (expr->getStmtClass() != Stmt::BinaryOperatorClass)
+		return extract_implicit_condition(expr);
 
 	comp = cast<BinaryOperator>(expr);
 	switch (comp->getOpcode()) {
@@ -863,8 +871,7 @@ __isl_give isl_set *PetScan::extract_condition(Expr *expr)
 	case BO_LOr:
 		return extract_boolean(comp);
 	default:
-		unsupported(expr);
-		return NULL;
+		return extract_implicit_condition(expr);
 	}
 }
 
diff --git a/scan.h b/scan.h
index 755233b..deae095 100644
--- a/scan.h
+++ b/scan.h
@@ -123,6 +123,8 @@ private:
 	__isl_give isl_pw_aff *extract_affine(clang::ArraySubscriptExpr *expr);
 	__isl_give isl_pw_aff *extract_affine(clang::ConditionalOperator *expr);
 
+	__isl_give isl_set *extract_implicit_condition(clang::Expr *expr);
+
 	__isl_give isl_set *extract_condition(clang::UnaryOperator *expr);
 	__isl_give isl_set *extract_condition(clang::Expr *expr);
 	__isl_give isl_set *extract_comparison(clang::BinaryOperator *expr);
diff --git a/tests/implicit_condition.c b/tests/implicit_condition.c
new file mode 100644
index 0000000..77e8835
--- /dev/null
+++ b/tests/implicit_condition.c
@@ -0,0 +1,11 @@
+void foo(int N)
+{
+	int i;
+	int a[N];
+
+#pragma scop
+	for (i = 0; i < N; ++i)
+		if (i)
+			a[i] = i;
+#pragma endscop
+}
diff --git a/tests/implicit_condition.scop b/tests/implicit_condition.scop
new file mode 100644
index 0000000..6968433
--- /dev/null
+++ b/tests/implicit_condition.scop
@@ -0,0 +1,21 @@
+context: '[N] -> { [] : N >= 0 }'
+arrays:
+- context: '[N] -> { [] : N >= 0 }'
+  extent: '[N] -> { a[i0] : i0 >= 0 and i0 <= -1 + N }'
+  element_type: int
+statements:
+- line: 9
+  domain: '[N] -> { S_0[i] : i <= -1 + N and i >= 1 }'
+  schedule: '[N] -> { S_0[i] -> [0, i] }'
+  body:
+    type: binary
+    operation: =
+    arguments:
+    - type: access
+      relation: '[N] -> { S_0[i] -> a[i] }'
+      read: 0
+      write: 1
+    - type: access
+      relation: '[N] -> { S_0[i] -> [i] }'
+      read: 1
+      write: 0
-- 
2.11.4.GIT