re PR other/15526 (-ftrapv aborts on 0 * (-1))

	PR other/15526
	* libgcc2.c (__mulvsi3): Fix overflow test.
	* gcc.dg/ftrapv-1.c: New test case.

From-SVN: r82042

gcc/ChangeLog

+2004-05-20  Falk Hueffner  <falk@debian.org>
+
+	PR other/15526
+	* libgcc2.c (__mulvsi3): Fix overflow test.
+
 2004-05-19  Andrew Pinski  <pinskia@physics.uc.edu>
 
 	PR c/14171

gcc/libgcc2.c

@@ -130,9 +130,7 @@ __mulvsi3 (Wtype a, Wtype b)
 {
   const DWtype w = (DWtype) a * (DWtype) b;
 
-  if (((a >= 0) == (b >= 0))
-      ? (UDWtype) w > (UDWtype) (((DWtype) 1 << (WORD_SIZE - 1)) - 1)
-      : (UDWtype) w < (UDWtype) ((DWtype) -1 << (WORD_SIZE - 1)))
+  if ((Wtype) (w >> WORD_SIZE) != (Wtype) w >> (WORD_SIZE - 1))
     abort ();
 
   return w;

gcc/testsuite/ChangeLog

+2004-05-20  Falk Hueffner  <falk@debian.org>
+
+	PR other/15526
+	* gcc.dg/ftrapv-1.c: New test case.
+
 2004-05-18  Feng Wang  <fengwang@nudt.edu.cn>
 
 	* gfortran.fortran-torture/execute/power.f90: Test constant integers.

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

+/* Copyright (C) 2004 Free Software Foundation.
+
+   PR other/15526
+   Verify correct overflow checking with -ftrapv.
+
+   Written by Falk Hueffner, 20th May 2004.  */
+
+/* { dg-do run } */
+/* { dg-options "-ftrapv" } */
+
+__attribute__((noinline)) int
+mulv(int a, int b)
+{
+  return a * b;
+}
+
+int
+main()
+{
+  mulv( 0,  0);
+  mulv( 0, -1);
+  mulv(-1,  0);
+  mulv(-1, -1);
+  return 0;
+}