re PR c/39035 (if( 0.0DF ) is considered true)

	PR c/39035
	* real.c (do_compare): Special-case compare of zero against
	decimal float value.

	* gcc.dg/dfp/pr39035.c: New test.

From-SVN: r143992

gcc/ChangeLog

+2009-02-06  Janis Johnson  <janis187@us.ibm.com>
+
+	PR c/39035
+	* real.c (do_compare): Special-case compare of zero against
+	decimal float value.
+
 2009-02-06  Joseph Myers  <joseph@codesourcery.com>
 
 	PR c/36432

gcc/real.c

@@ -905,15 +905,23 @@ do_compare (const REAL_VALUE_TYPE *a, const REAL_VALUE_TYPE *b,
       /* Sign of zero doesn't matter for compares.  */
       return 0;
 
+    case CLASS2 (rvc_normal, rvc_zero):
+      /* Decimal float zero is special and uses rvc_normal, not rvc_zero.  */
+      if (a->decimal)
+	return decimal_do_compare (a, b, nan_result);
+      /* Fall through.  */
     case CLASS2 (rvc_inf, rvc_zero):
     case CLASS2 (rvc_inf, rvc_normal):
-    case CLASS2 (rvc_normal, rvc_zero):
       return (a->sign ? -1 : 1);
 
     case CLASS2 (rvc_inf, rvc_inf):
       return -a->sign - -b->sign;
 
     case CLASS2 (rvc_zero, rvc_normal):
+      /* Decimal float zero is special and uses rvc_normal, not rvc_zero.  */
+      if (b->decimal)
+	return decimal_do_compare (a, b, nan_result);
+      /* Fall through.  */
     case CLASS2 (rvc_zero, rvc_inf):
     case CLASS2 (rvc_normal, rvc_inf):
       return (b->sign ? 1 : -1);

gcc/testsuite/ChangeLog

+2009-02-06  Janis Johnson  <janis187@us.ibm.com>
+
+	PR c/39035
+	* gcc.dg/dfp/pr39035.c: New test.
+
 2009-02-06  Joseph Myers  <joseph@codesourcery.com>
 
 	PR c/36432

gcc/testsuite/gcc.dg/dfp/pr39035.c

+/* { dg-do run } */
+/* { dg-options "-std=gnu99 -O" } */
+
+/* DFP TR 24732 == WG14 / N1176, N1312 */
+/* Based on a test from Fred Tydeman.  */
+
+extern void abort (void);
+int failures = 0;
+
+#ifdef DBG
+#include <stdio.h>
+#define FAILURE(MSG) { printf ("line %d: %s\n", __LINE__, MSG); failures++; }
+#else
+#define FAILURE(MSG) failures++;
+#endif
+
+/* Test runtime computations.  */
+
+void
+runtime32 (void)
+{
+  volatile _Decimal32 d;
+  d = 0.0DF;
+  if (d)
+    FAILURE ("0.0DF should be zero")
+}
+
+void
+runtime64 (void)
+{
+  volatile _Decimal64 d;
+  d = 0.0DD;
+  if (d)
+    FAILURE ("0.0DD should be zero")
+}
+
+void
+runtime128 (void)
+{
+  volatile _Decimal128 d;
+  d = 0.0DL;
+  if (d)
+    FAILURE ("0.0DL should be zero")
+}
+
+void
+fold32 (void)
+{
+  if (0.0DF)
+    FAILURE ("0.0DF should be zero")
+}
+
+void
+fold64 (void)
+{
+  if (0.0DD)
+    FAILURE ("0.0DD should be zero")
+}
+
+void
+fold128 (void)
+{
+  if (0.0DL)
+    FAILURE ("0.0DL should be zero")
+}
+
+int
+main(void)
+{
+  runtime32 ();
+  runtime64 ();
+  runtime128 ();
+
+  fold32 ();
+  fold64 ();
+  fold128 ();
+
+  if (failures != 0)
+    abort ();
+  return 0;
+}