From 9e96b8d0709ef64d2c13cdb7cadcc306ddc06953 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 13 Sep 2012 17:25:15 -0700
Subject: Warn pointer to signed integer cast for ilp32

---
 gcc/c-family/c.opt                                 |  4 ++++
 gcc/c/c-typeck.c                                   | 23 +++++++++++++---------
 gcc/cp/typeck.c                                    |  5 +++++
 .../g++.dg/warn/Wpointer-to-signed-int-cast-1.C    | 23 ++++++++++++++++++++++
 .../gcc.dg/Wpointer-to-signed-int-cast-1.c         | 17 ++++++++++++++++
 5 files changed, 63 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/warn/Wpointer-to-signed-int-cast-1.C
 create mode 100644 gcc/testsuite/gcc.dg/Wpointer-to-signed-int-cast-1.c

diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 914d110597d..0f5d941b921 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -581,6 +581,10 @@ Wpointer-to-int-cast
 C ObjC Var(warn_pointer_to_int_cast) Init(1) Warning
 Warn when a pointer is cast to an integer of a different size
 
+Wpointer-to-signed-int-cast
+C ObjC C++ ObjC++ Var(warn_pointer_to_signed_int_cast) Warning
+Warn when a pointer is cast to a signed integer of the same size
+
 Wpragmas
 C ObjC C++ ObjC++ Var(warn_pragmas) Init(1) Warning
 Warn about misuses of pragmas
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index 99920ef288b..b401edc6507 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -4657,15 +4657,20 @@ build_c_cast (location_t loc, tree type, tree expr)
 		    "cast increases required alignment of target type");
 
       if (TREE_CODE (type) == INTEGER_TYPE
-	  && TREE_CODE (otype) == POINTER_TYPE
-	  && TYPE_PRECISION (type) != TYPE_PRECISION (otype))
-      /* Unlike conversion of integers to pointers, where the
-         warning is disabled for converting constants because
-         of cases such as SIG_*, warn about converting constant
-         pointers to integers. In some cases it may cause unwanted
-         sign extension, and a warning is appropriate.  */
-	warning_at (loc, OPT_Wpointer_to_int_cast,
-		    "cast from pointer to integer of different size");
+	  && TREE_CODE (otype) == POINTER_TYPE)
+	{
+	  if (TYPE_PRECISION (type) != TYPE_PRECISION (otype))
+	    /* Unlike conversion of integers to pointers, where the
+	       warning is disabled for converting constants because
+	       of cases such as SIG_*, warn about converting constant
+	       pointers to integers. In some cases it may cause unwanted
+	       sign extension, and a warning is appropriate.  */
+	    warning_at (loc, OPT_Wpointer_to_int_cast,
+			"cast from pointer to integer of different size");
+	  else if (!TYPE_UNSIGNED (type) && ptr_mode != word_mode)
+	    warning_at (loc, OPT_Wpointer_to_signed_int_cast,
+			"cast from pointer to signed integer");
+	}
 
       if (TREE_CODE (value) == CALL_EXPR
 	  && TREE_CODE (type) != TREE_CODE (otype))
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 25f37e896fa..3ce10812180 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -6374,6 +6374,11 @@ build_reinterpret_cast_1 (tree type, tree expr, bool c_cast_p,
           else
             return error_mark_node;
         }
+      else if (TYPE_PRECISION (type) == TYPE_PRECISION (intype)
+	       && !TYPE_UNSIGNED (type)
+	       && ptr_mode != word_mode)
+	warning_at (input_location, OPT_Wpointer_to_signed_int_cast,
+		    "cast from %qT to %qT", intype, type);
       if (NULLPTR_TYPE_P (intype))
         return build_int_cst (type, 0);
     }
diff --git a/gcc/testsuite/g++.dg/warn/Wpointer-to-signed-int-cast-1.C b/gcc/testsuite/g++.dg/warn/Wpointer-to-signed-int-cast-1.C
new file mode 100644
index 00000000000..f951056bc7d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wpointer-to-signed-int-cast-1.C
@@ -0,0 +1,23 @@
+// Test -Wpointer-to-signed-int-cast - off by default.
+// { dg-do compile { target { int128 && ilp32 } } }
+// { dg-options "-Wpointer-to-signed-int-cast" }
+
+void *p;
+
+long
+foo (void)
+{
+  return (long) p; // { dg-warning "cast from 'void\\*' to 'long int'" } 
+}
+
+unsigned long
+bar (void)
+{
+  return (unsigned long) p;
+}
+
+long long
+xxx (void)
+{
+  return (long long) p;
+}
diff --git a/gcc/testsuite/gcc.dg/Wpointer-to-signed-int-cast-1.c b/gcc/testsuite/gcc.dg/Wpointer-to-signed-int-cast-1.c
new file mode 100644
index 00000000000..5d265d8a28a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wpointer-to-signed-int-cast-1.c
@@ -0,0 +1,17 @@
+/* Test -Wpointer-to-signed-int-cast - off by default.  */
+/* { dg-do compile { target { int128 && ilp32 } } } */
+/* { dg-options "-Wpointer-to-signed-int-cast" } */
+
+void *p;
+
+long
+foo (void)
+{
+  return (long) p; /* { dg-warning "cast from pointer to signed integer" } */
+}
+
+unsigned long
+bar (void)
+{
+  return (unsigned long) p;
+}
-- 
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