diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2b4062aeae3..ed3129dc38b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2008-08-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/37103
+	* fold-const.c (fold_widened_comparison): Do not allow
+	sign changes that change the result even if shorter type
+	is wider than arg1_unw's type.
+
 2008-08-13  Kazu Hirata  <kazu@codesourcery.com>
 
 	* gcc.dg/arm-g2.c, gcc.dg/arm-mmx-1.c, gcc.dg/arm-scd42-2.c:
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index cae45b5a658..eac31ef1a79 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -6733,10 +6733,8 @@ fold_widened_comparison (enum tree_code code, tree type, tree arg0, tree arg1)
   if ((code == EQ_EXPR || code == NE_EXPR
        || TYPE_UNSIGNED (TREE_TYPE (arg0)) == TYPE_UNSIGNED (shorter_type))
       && (TREE_TYPE (arg1_unw) == shorter_type
-	  || (TYPE_PRECISION (shorter_type)
-	      > TYPE_PRECISION (TREE_TYPE (arg1_unw)))
 	  || ((TYPE_PRECISION (shorter_type)
-	       == TYPE_PRECISION (TREE_TYPE (arg1_unw)))
+	       >= TYPE_PRECISION (TREE_TYPE (arg1_unw)))
 	      && (TYPE_UNSIGNED (shorter_type)
 		  == TYPE_UNSIGNED (TREE_TYPE (arg1_unw))))
 	  || (TREE_CODE (arg1_unw) == INTEGER_CST
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f4d6909f93d..ca3aa25161e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2008-08-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/37103
+	* gcc.c-torture/execute/20080813-1.c: New test.
+
 2008-08-13  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* gcc.target/i386/incoming-1.c: Skip *-*-darwin*.
diff --git a/gcc/testsuite/gcc.c-torture/execute/20080813-1.c b/gcc/testsuite/gcc.c-torture/execute/20080813-1.c
new file mode 100644
index 00000000000..9ef6bc2e2c5
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20080813-1.c
@@ -0,0 +1,30 @@
+/* PR middle-end/37103 */
+
+extern void abort (void);
+
+void
+foo (unsigned short x)
+{
+  signed char y = -1;
+  if (x == y)
+    abort ();
+}
+
+void
+bar (unsigned short x)
+{
+  unsigned char y = -1;
+  if (x == y)
+    abort ();
+}
+
+int
+main (void)
+{
+  if (sizeof (int) == sizeof (short))
+    return 0;
+  foo (-1);
+  if (sizeof (short) > 1)
+    bar (-1);
+  return 0;
+}