From: Stefan Liebler <stli@linux.vnet.ibm.com>
Date: Tue, 29 Apr 2014 13:43:36 +0000 (+0200)
Subject: [BZ #16823] Fix log1pl returning wrong infinity sign
X-Git-Tag: upstream/2.30~7585
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2ca180e97a16f3ee3ec9e7e5a5fb7eda3d863a02;p=external%2Fglibc.git

[BZ #16823] Fix log1pl returning wrong infinity sign
---

diff --git a/ChangeLog b/ChangeLog
index 4007295..803d114 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-04-29  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	[BZ #16823]
+	* sysdeps/ieee754/ldbl-128/s_log1pl.c (__log1pl):
+	Always divide by positive zero when computing -Inf result.
+	* sysdeps/ieee754/dbl-64/s_log1p.c (__log1p): Likewise.
+	* sysdeps/ieee754/flt-32/s_log1pf.c (__log1pf): Likewise.
+
 2014-04-28  Adhemerval Zanella  <azanella@linux.vnet.ibm.com>
 
 	* sysdeps/powerpc/fpu/fclrexcpt.c (__feclearexcept): Do not update
diff --git a/sysdeps/ieee754/dbl-64/s_log1p.c b/sysdeps/ieee754/dbl-64/s_log1p.c
index fd4dce5..c922148 100644
--- a/sysdeps/ieee754/dbl-64/s_log1p.c
+++ b/sysdeps/ieee754/dbl-64/s_log1p.c
@@ -110,7 +110,7 @@ __log1p (double x)
       if (__glibc_unlikely (ax >= 0x3ff00000))           /* x <= -1.0 */
 	{
 	  if (x == -1.0)
-	    return -two54 / (x - x);            /* log1p(-1)=+inf */
+	    return -two54 / zero;               /* log1p(-1)=-inf */
 	  else
 	    return (x - x) / (x - x);           /* log1p(x<-1)=NaN */
 	}
diff --git a/sysdeps/ieee754/flt-32/s_log1pf.c b/sysdeps/ieee754/flt-32/s_log1pf.c
index 0307277..5f00feb 100644
--- a/sysdeps/ieee754/flt-32/s_log1pf.c
+++ b/sysdeps/ieee754/flt-32/s_log1pf.c
@@ -42,7 +42,7 @@ __log1pf(float x)
 	k = 1;
 	if (hx < 0x3ed413d7) {			/* x < 0.41422  */
 	    if(ax>=0x3f800000) {		/* x <= -1.0 */
-		if(x==(float)-1.0) return -two25/(x-x); /* log1p(-1)=+inf */
+		if(x==(float)-1.0) return -two25/zero; /* log1p(-1)=-inf */
 		else return (x-x)/(x-x);	/* log1p(x<-1)=NaN */
 	    }
 	    if(ax<0x31000000) {			/* |x| < 2**-29 */
diff --git a/sysdeps/ieee754/ldbl-128/s_log1pl.c b/sysdeps/ieee754/ldbl-128/s_log1pl.c
index d991e8a..d8d89f0 100644
--- a/sysdeps/ieee754/ldbl-128/s_log1pl.c
+++ b/sysdeps/ieee754/ldbl-128/s_log1pl.c
@@ -150,7 +150,7 @@ __log1pl (long double xm1)
   if (x <= 0.0L)
     {
       if (x == 0.0L)
-	return (-1.0L / (x - x));
+	return (-1.0L / zero);  /* log1p(-1) = -inf */
       else
 	return (zero / (x - x));
     }