re PR c/27273 (tree check fail for legal code when convert returns a constant…

re PR c/27273 (tree check fail for legal code when convert returns a constant from an expression that was not constant)

        PR c/27273
        * c-common.c (convert_and_check): only track TREE_CONSTANT_OVERFLOW
        for CONSTANT_CLASS_P expressions.

        * gcc.dg/overflow-warn-5.c: New testcase.

From-SVN: r114238

gcc/ChangeLog

+2006-05-30  Dirk Mueller  <dmueller@suse.de>
+
+	PR c/27273
+	* c-common.c (convert_and_check): Only track TREE_CONSTANT_OVERFLOW
+	for CONSTANT_CLASS_P expresisons.
+
 2006-05-30  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
 	PR c/27718

gcc/c-common.c

@@ -1083,7 +1083,8 @@ convert_and_check (tree type, tree expr)
 
 	  /* Do not diagnose overflow in a constant expression merely
 	     because a conversion overflowed.  */
-	  TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (expr);
+	  TREE_CONSTANT_OVERFLOW (t) = CONSTANT_CLASS_P (expr)
+                                       && TREE_CONSTANT_OVERFLOW (expr);
 
 	  /* No warning for converting 0x80000000 to int.  */
 	  if (!(TYPE_UNSIGNED (type) < TYPE_UNSIGNED (TREE_TYPE (expr))

gcc/testsuite/ChangeLog

+2006-05-30  Dirk Mueller  <dmueller@suse.de>
+
+	PR c/27273
+	* gcc.dg/overflow-warn-5.c: New test.
+
 2006-05-30  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
 	PR c/27718

gcc/testsuite/gcc.dg/overflow-warn-5.c

+/* PR c/27273 */
+/* { dg-do compile } */
+/* { dg-options "-Woverflow" } */
+
+unsigned char rx_async(unsigned char p) {
+    return p & 512; /* { dg-warning "overflow in implicit constant conversion" } */
+}