From: Richard Henderson <rth@redhat.com>
Date: Fri, 26 Apr 2002 02:15:52 +0000 (-0700)
Subject: re PR c/2098 (compare with unsigned variable - no error reporting)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5c5b22838958187f83bf60d0394cc06942796646;p=gcc.git

re PR c/2098 (compare with unsigned variable - no error reporting)

        PR c/2098
        * c-common.c (shorten_compare): Simplfy conditions leading to
        the generation of a warning.

	* gcc.dg/compare6.c: New.

From-SVN: r52778
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 76182b9a144..2813ca25792 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2002-04-25  Richard Henderson  <rth@redhat.com>
+
+	PR c/2098
+	* c-common.c (shorten_compare): Simplfy conditions leading to
+	the generation of a warning.
+
 2002-04-25  Richard Henderson  <rth@redhat.com>
 
 	PR c/2035
diff --git a/gcc/c-common.c b/gcc/c-common.c
index 03966a87c25..f9337df907f 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -1999,19 +1999,8 @@ shorten_compare (op0_ptr, op1_ptr, restype_ptr, rescode_ptr)
 	  type = c_common_unsigned_type (type);
 	}
 
-      if (!max_gt && !unsignedp0 && TREE_CODE (primop0) != INTEGER_CST)
+      if (TREE_CODE (primop0) != INTEGER_CST)
 	{
-	  /* This is the case of (char)x >?< 0x80, which people used to use
-	     expecting old C compilers to change the 0x80 into -0x80.  */
-	  if (val == boolean_false_node)
-	    warning ("comparison is always false due to limited range of data type");
-	  if (val == boolean_true_node)
-	    warning ("comparison is always true due to limited range of data type");
-	}
-
-      if (!min_lt && unsignedp0 && TREE_CODE (primop0) != INTEGER_CST)
-	{
-	  /* This is the case of (unsigned char)x >?< -1 or < 0.  */
 	  if (val == boolean_false_node)
 	    warning ("comparison is always false due to limited range of data type");
 	  if (val == boolean_true_node)
diff --git a/gcc/testsuite/gcc.dg/compare6.c b/gcc/testsuite/gcc.dg/compare6.c
new file mode 100644
index 00000000000..fbeb6a0aedd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/compare6.c
@@ -0,0 +1,13 @@
+/* PR c/2098 */
+/* Test for a warning on comparison on out-of-range data.  */
+/* { dg-do compile { xfail c4x-*-* } } */
+/* { dg-options "-Wall" } */
+
+signed char sc;
+unsigned char uc;
+
+void foo()
+{
+  if (sc == 10000) return; /* { dg-warning "always false" "signed" } */
+  if (uc == 10000) return; /* { dg-warning "always false" "unsigned" } */
+}