From 314b93ea9a11200b8b5480588f38d406cdb8d741 Mon Sep 17 00:00:00 2001
From: jsm28 <jsm28@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Fri, 29 Jul 2005 01:24:38 +0000
Subject: [PATCH] 	PR c/21720 	* real.c (real_from_string): Set last
 bit if there is a nonzero 	hex digit beyond GCC's internal precision.

testsuite:
	* gcc.dg/hex-round-1.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@102539 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                      |  6 ++++++
 gcc/real.c                         |  4 ++++
 gcc/testsuite/ChangeLog            |  5 +++++
 gcc/testsuite/gcc.dg/hex-round-1.c | 31 +++++++++++++++++++++++++++++++
 4 files changed, 46 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/hex-round-1.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 070443d860d..6f10df5e64e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-07-29  Joseph S. Myers  <joseph@codesourcery.com>
+
+	PR c/21720
+	* real.c (real_from_string): Set last bit if there is a nonzero
+	hex digit beyond GCC's internal precision.
+
 2005-07-28  Richard Henderson  <rth@redhat.com>
 
 	PR rtl-opt/22619
diff --git a/gcc/real.c b/gcc/real.c
index 9099f410f8d..045a803a594 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -1789,6 +1789,10 @@ real_from_string (REAL_VALUE_TYPE *r, const char *str)
 		|= (unsigned long) d << (pos % HOST_BITS_PER_LONG);
 	      pos -= 4;
 	    }
+	  else if (d)
+	    /* Ensure correct rounding by setting last bit if there is
+	       a subsequent nonzero digit.  */
+	    r->sig[0] |= 1;
 	  exp += 4;
 	  str++;
 	}
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a8badc528d3..45f6324e3a5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2005-07-29  Joseph S. Myers  <joseph@codesourcery.com>
+
+	PR c/21720
+	* gcc.dg/hex-round-1.c: New test.
+
 2005-07-28  Jan Hubicka  <jh@suse.cz>
 
 	* inliner-1.c: Do not dump everything.
diff --git a/gcc/testsuite/gcc.dg/hex-round-1.c b/gcc/testsuite/gcc.dg/hex-round-1.c
new file mode 100644
index 00000000000..1ce9c35c0fa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/hex-round-1.c
@@ -0,0 +1,31 @@
+/* Test for hexadecimal float rounding: bug 21720.  */
+/* { dg-do link } */
+/* { dg-options "-O -std=gnu99" } */
+
+#include <float.h>
+
+extern void link_failure (void);
+
+int
+main (void)
+{
+#if FLT_RADIX == 2 && FLT_MANT_DIG == 24
+  if (0x1.000001000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.0000010000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.00000100000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.000001000000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.0000010000000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.00000100000000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.000001000000000000000000000000000000000001p0f == 1)
+    link_failure ();
+  if (0x1.0000010000000000000000000000000000000000001p0f == 1)
+    link_failure ();
+#endif
+  return 0;
+}
-- 
2.11.0