re PR c/8224 (Incorrect joining of signed and unsigned division)

	PR c/8224
	* fold-const.c (extract_muldiv_1): Don't pass through type conversions
	when signedness changes for division or modulus.

	PR c/8224
	* gcc.dg/20030323-1.c: New test.

From-SVN: r64760

gcc/ChangeLog

+2003-03-23  Glen Nakamura <glen@imodulo.com>
+
+	PR c/8224
+	* fold-const.c (extract_muldiv_1): Don't pass through type conversions
+	when signedness changes for division or modulus.
+
 2003-03-24  Alan Modra  <amodra@bigpond.net.au>
 
 	* config/rs6000/sysv4.h (ASM_OUTPUT_ALIGNED_BSS): Remove unnecessary

gcc/fold-const.c

@@ -4170,7 +4170,12 @@ extract_muldiv_1 (t, c, code, wide_type)
 	      /* ... or its type is larger than ctype,
 		 then we cannot pass through this truncation.  */
 	      || (GET_MODE_SIZE (TYPE_MODE (ctype))
-		  < GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0))))))
+		  < GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0))))
+	      /* ... or signedness changes for division or modulus,
+		 then we cannot pass through this conversion.  */
+	      || (code != MULT_EXPR
+		  && (TREE_UNSIGNED (ctype)
+		      != TREE_UNSIGNED (TREE_TYPE (op0))))))
 	break;
 
       /* Pass the constant down and see if we can make a simplification.  If

gcc/testsuite/ChangeLog

+2003-03-23  Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
+
+	PR c/8224
+	* gcc.dg/20030323-1.c: New test.
+
 2003-03-23  Roger Sayle  <roger@eyesopen.com>
 
 	* gcc.c-torture/compile/20030323-1.c: New test case.

gcc/testsuite/gcc.dg/20030323-1.c

+/* { dg-do run } */
+
+/* PR c/8224 */
+/* Contributed by Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> */
+
+extern void abort (void);
+
+unsigned f (int x)
+{
+  return (unsigned) (x / 2) / 2;
+}
+
+unsigned f1 (int x)
+{
+  unsigned xx = x / 2;
+  return xx / 2;
+}
+
+int main ()
+{
+  if (f1 (-5) != f (-5))
+    abort ();
+  return 0;
+}