From d9f85de2a188da9e5af0ec34acba7699ac5e330c Mon Sep 17 00:00:00 2001
From: Christian Kamm <kamm@incasoftware.de>
Date: Mon, 28 Jul 2008 21:37:47 +0200
Subject: [PATCH] Fix real comparison for real: allow +0 to be distinguished
 from -0.

---
 dmd/expression.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/dmd/expression.c b/dmd/expression.c
index f0ed8ebd..bf1665b7 100644
--- a/dmd/expression.c
+++ b/dmd/expression.c
@@ -1494,11 +1494,12 @@ complex_t RealExp::toComplex()
 
 int RealEquals(real_t x1, real_t x2)
 {
-    return (isnan(x1) && isnan(x2)) ||
-	/* In some cases, the REALPAD bytes get garbage in them,
-	 * so be sure and ignore them.
-	 */
-	x1 == x2;
+    return // special case nans
+	   (isnan(x1) && isnan(x2)) ||
+	   // and zero, in order to distinguish +0 from -0
+	   (x1 == 0 && x2 == 0 && 1./x1 == 1./x2) ||
+	   // otherwise just compare
+	   (x1 != 0. && x1 == x2);
 }
 
 int RealExp::equals(Object *o)