From: John David Anglin <danglin@gcc.gnu.org>
Date: Wed, 17 Apr 2019 00:22:23 +0000 (+0000)
Subject: re PR libfortran/79540 (FAIL: gfortran.dg/fmt_fw_d.f90   -O0  execution test)
X-Git-Tag: releases/gcc-7.5.0~481
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ba3209c010f3cda5e022387d7e788e1867f21e75;p=thirdparty%2Fgcc.git

re PR libfortran/79540 (FAIL: gfortran.dg/fmt_fw_d.f90   -O0  execution test)

	PR libgfortran/79540
	* io/write_float.def (build_float_string): Don't copy digits when
	ndigits is negative.

From-SVN: r270402
---

diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index 219b1ffd89ad..5ead90f9e4c2 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,12 @@
+2019-04-16  John David Anglin  <danglin@gcc.gnu.org>
+
+	Backport from mainline
+	2019-03-25  John David Anglin  <danglin@gcc.gnu.org>
+
+	PR libgfortran/79540
+	* io/write_float.def (build_float_string): Don't copy digits when
+	ndigits is negative.
+
 2019-02-03  Uroš Bizjak  <ubizjak@gmail.com>
 
 	PR libfortran/88678
diff --git a/libgfortran/io/write_float.def b/libgfortran/io/write_float.def
index b4971fd335e8..e303f7d73a85 100644
--- a/libgfortran/io/write_float.def
+++ b/libgfortran/io/write_float.def
@@ -620,14 +620,15 @@ build_float_string (st_parameter_dt *dtp, const fnode *f, char *buffer,
     }
 
   /* Set digits after the decimal point, padding with zeros.  */
-  if (nafter > 0)
+  if (ndigits >= 0 && nafter > 0)
     {
       if (nafter > ndigits)
 	i = ndigits;
       else
 	i = nafter;
 
-      memcpy (put, digits, i);
+      if (i > 0)
+	memcpy (put, digits, i);
       while (i < nafter)
 	put[i++] = '0';