From: Mark Mitchell <mmitchel@gcc.gnu.org>
Date: Sun, 23 Mar 2003 22:57:26 +0000 (+0000)
Subject: re PR c/8224 (Incorrect joining of signed and unsigned division)
X-Git-Tag: releases/gcc-3.4.0~7711
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=068d2c9db6aa8553b34925ea0c0957e8ce671e30;p=thirdparty%2Fgcc.git

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
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fc8f41838f79..596e91e09848 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+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
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 7b051fa8a6eb..0f9f3d419a57 100644
--- a/gcc/fold-const.c
+++ b/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
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 05b170ca1850..9db85358f04b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+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.
diff --git a/gcc/testsuite/gcc.dg/20030323-1.c b/gcc/testsuite/gcc.dg/20030323-1.c
new file mode 100644
index 000000000000..8a563ec5eb21
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/20030323-1.c
@@ -0,0 +1,24 @@
+/* { 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;
+}