Add minus zero test

From-SVN: r20152

gcc/testsuite/gcc.c-torture/ChangeLog

@@ -1,3 +1,7 @@
+Sun May 31 23:23:29 1998  Michael Meissner  <meissner@cygnus.com>
+
+	* execute/ieee/mzero2.c: New test to better test IEEE -0 support.
+
 Wed Apr  8 13:09:15 1998  Jim Wilson  <wilson@cygnus.com>
 
 	* execute/980407-1.c: Delete test.  Is duplicate of loop-4.c.

gcc/testsuite/gcc.c-torture/execute/ieee/mzero2.c

@@ -0,0 +1,58 @@
+/* Test IEEE +0/-0 rules */
+
+static double pzero = +0.0;
+static double nzero = -0.0;
+static double pinf  = +1.0 / 0.0;
+static double ninf  = -1.0 / 0.0;
+static double nan   =  0.0 / 0.0;
+
+void
+expect (double value, double expected)
+{
+  if (expected != expected)	/* expected value is Not a number */
+    {
+      if (value == value)	/* actual value is a number */
+	abort ();
+    }
+
+  else if (value != value)
+    abort ();			/* actual value is a NaN */
+
+  else if (memcmp ((void *)&value, (void *)&expected, sizeof (double)) != 0)
+    abort ();			/* values don't match */
+}
+
+main ()
+{
+  expect (pzero + pzero, pzero);
+  expect (pzero + nzero, pzero);
+  expect (nzero + pzero, pzero);
+  expect (nzero + nzero, nzero);
+
+  expect (pzero - pzero, pzero);
+  expect (pzero - nzero, pzero);
+  expect (nzero - pzero, nzero);
+  expect (nzero - nzero, pzero);
+
+  expect (pzero * pzero, pzero);
+  expect (pzero * nzero, nzero);
+  expect (nzero * pzero, nzero);
+  expect (nzero * nzero, pzero);
+
+  expect (+1.00 * pzero, pzero);
+  expect (-1.00 * pzero, nzero);
+  expect (+1.00 * nzero, nzero);
+  expect (-1.00 * nzero, pzero);
+
+  expect (pzero / pzero, nan);
+  expect (pzero / nzero, nan);
+  expect (nzero / pzero, nan);
+  expect (nzero / nzero, nan);
+
+  expect (+1.00 / pzero, pinf);
+  expect (-1.00 / pzero, ninf);
+  expect (+1.00 / nzero, ninf);
+  expect (-1.00 / nzero, pinf);
+
+  exit (0);
+}