5 files changed, 70 insertions, 2 deletions
diff --git a/evaluate.c b/evaluate.c
index 7ab7db81..6d5d4793 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -3003,14 +3003,14 @@ static struct symbol *evaluate_cast(struct expression *expr)
 		}
 	}
 
-	if (ttype == &ulong_ctype)
+	if (ttype == &ulong_ctype && !Wcast_from_as)
 		tas = -1;
 	else if (tclass == TYPE_PTR) {
 		examine_pointer_target(ttype);
 		tas = ttype->ctype.as;
 	}
 
-	if (stype == &ulong_ctype)
+	if (stype == &ulong_ctype && !Wcast_from_as)
 		sas = -1;
 	else if (sclass == TYPE_PTR) {
 		examine_pointer_target(stype);
diff --git a/lib.c b/lib.c
index 48c6dc98..652780ae 100644
--- a/lib.c
+++ b/lib.c
@@ -248,6 +248,7 @@ static struct token *pre_buffer_end = NULL;
 int Waddress = 0;
 int Waddress_space = 1;
 int Wbitwise = 1;
+int Wcast_from_as = 0;
 int Wcast_to_as = 0;
 int Wcast_truncate = 1;
 int Wconstexpr_not_const = 0;
@@ -682,6 +683,7 @@ static const struct flag warnings[] = {
 	{ "address", &Waddress },
 	{ "address-space", &Waddress_space },
 	{ "bitwise", &Wbitwise },
+	{ "cast-from-as", &Wcast_from_as },
 	{ "cast-to-as", &Wcast_to_as },
 	{ "cast-truncate", &Wcast_truncate },
 	{ "constexpr-not-const", &Wconstexpr_not_const},
diff --git a/lib.h b/lib.h
index 8b445204..cd1af9c4 100644
--- a/lib.h
+++ b/lib.h
@@ -138,6 +138,7 @@ extern int preprocess_only;
 extern int Waddress;
 extern int Waddress_space;
 extern int Wbitwise;
+extern int Wcast_from_as;
 extern int Wcast_to_as;
 extern int Wcast_truncate;
 extern int Wconstexpr_not_const;
diff --git a/sparse.1 b/sparse.1
index 8a14a6be..3e135235 100644
--- a/sparse.1
+++ b/sparse.1
@@ -77,6 +77,15 @@ Sparse issues these warnings by default.  To turn them off, use
 \fB\-Wno\-bitwise\fR.
 .
 .TP
+.B \-Wcast\-from\-as
+Warn about which remove an address space to a pointer type.
+
+This is similar to \fB\-Waddress\-space\fR but will also warn
+on casts to \fBunsigned long\fR.
+
+Sparse does not issues these warnings by default.
+.
+.TP
 .B \-Wcast\-to\-as
 Warn about casts which add an address space to a pointer type.
 
diff --git a/validation/Waddress-space-strict.c b/validation/Waddress-space-strict.c
new file mode 100644
index 00000000..5071aab2
--- /dev/null
+++ b/validation/Waddress-space-strict.c
@@ -0,0 +1,56 @@
+#define __user __attribute__((address_space(1)))
+
+typedef unsigned long ulong;
+typedef long long llong;
+typedef struct s obj_t;
+
+static void expl(int i, ulong u, llong l, void *v, obj_t *o, obj_t __user *p)
+{
+	(obj_t*)(i);
+	(obj_t __user*)(i);
+
+	(obj_t*)(u);
+	(obj_t __user*)(u);
+
+	(obj_t*)(l);
+	(obj_t __user*)(l);
+
+	(obj_t*)(v);
+	(obj_t __user*)(v);
+
+	(int)(o);
+	(ulong)(o);
+	(llong)(o);
+	(void *)(o);
+	(obj_t*)(o);
+	(obj_t __user*)(o);
+
+	(int)(p);		// w
+	(ulong)(p);		// w!
+	(llong)(p);		// w
+	(void *)(p);		// w
+	(obj_t*)(p);		// w
+	(obj_t __user*)(p);	// ok
+}
+
+/*
+ * check-name: Waddress-space-strict
+ * check-command: sparse -Wcast-from-as -Wcast-to-as $file
+ *
+ * check-error-start
+Waddress-space-strict.c:10:10: warning: cast adds address space to expression (<asn:1>)
+Waddress-space-strict.c:13:10: warning: cast adds address space to expression (<asn:1>)
+Waddress-space-strict.c:16:10: warning: cast adds address space to expression (<asn:1>)
+Waddress-space-strict.c:19:10: warning: cast adds address space to expression (<asn:1>)
+Waddress-space-strict.c:26:10: warning: cast adds address space to expression (<asn:1>)
+Waddress-space-strict.c:28:10: warning: cast removes address space of expression
+Waddress-space-strict.c:29:10: warning: cast removes address space of expression
+Waddress-space-strict.c:30:10: warning: cast removes address space of expression
+Waddress-space-strict.c:31:10: warning: cast removes address space of expression
+Waddress-space-strict.c:32:10: warning: cast removes address space of expression
+Waddress-space-strict.c:9:18: warning: non size-preserving integer to pointer cast
+Waddress-space-strict.c:10:25: warning: non size-preserving integer to pointer cast
+Waddress-space-strict.c:21:15: warning: non size-preserving pointer to integer cast
+Waddress-space-strict.c:28:15: warning: non size-preserving pointer to integer cast
+ * check-error-end
+ */