For targets that have a signed zero, lgamma_r(-0, &signgamp) should

set signgamp = -1.

Submitted by:	enh at google dot com (e_lgamma[f]_r.c)

4 files changed, 20 insertions, 4 deletions

diff --git a/lib/msun/ld128/e_lgammal_r.c b/lib/msun/ld128/e_lgammal_r.c
index a612681d3d7d..13f8f75a46c6 100644
--- a/lib/msun/ld128/e_lgammal_r.c
+++ b/lib/msun/ld128/e_lgammal_r.c
@@ -241,7 +241,11 @@ lgammal_r(long double x, int *signgamp)
 	*signgamp = 1;
 	if((hx & 0x7fff) == 0x7fff)	/* x is +-Inf or NaN */
 		return x*x;
-	if((hx==0||hx==0x8000)&&lx==0) return one/vzero;
+	if((hx==0||hx==0x8000)&&lx==0) {
+	    if (hx&0x8000)
+		*signgamp = -1;
+	    return one/vzero;
+	}
 
    /* purge off tiny and negative arguments */
 	if(fabsl(x)<0x1p-119L) {
diff --git a/lib/msun/ld80/e_lgammal_r.c b/lib/msun/ld80/e_lgammal_r.c
index bafa9a3b04ef..621b04e74022 100644
--- a/lib/msun/ld80/e_lgammal_r.c
+++ b/lib/msun/ld80/e_lgammal_r.c
@@ -261,7 +261,11 @@ lgammal_r(long double x, int *signgamp)
 	*signgamp = 1;
 	if((hx & 0x7fff) == 0x7fff)	/* x is +-Inf or NaN */
 		return x*x;
-	if((hx==0||hx==0x8000)&&lx==0) return one/vzero;
+	if((hx==0||hx==0x8000)&&lx==0) {
+	    if (hx&0x8000)
+		*signgamp = -1;
+	    return one/vzero;
+	}
 
 	ENTERI();
 
diff --git a/lib/msun/src/e_lgamma_r.c b/lib/msun/src/e_lgamma_r.c
index ce2af94ca1c3..a6fd691ffd27 100644
--- a/lib/msun/src/e_lgamma_r.c
+++ b/lib/msun/src/e_lgamma_r.c
@@ -214,7 +214,11 @@ __ieee754_lgamma_r(double x, int *signgamp)
 	*signgamp = 1;
 	ix = hx&0x7fffffff;
 	if(ix>=0x7ff00000) return x*x;
-	if((ix|lx)==0) return one/vzero;
+	if((ix|lx)==0) {
+	   if(hx<0)
+		*signgamp = -1;
+	    return one/vzero;
+	}
 	if(ix<0x3b900000) {	/* |x|<2**-70, return -log(|x|) */
 	    if(hx<0) {
 	        *signgamp = -1;
diff --git a/lib/msun/src/e_lgammaf_r.c b/lib/msun/src/e_lgammaf_r.c
index f940845429d2..9d23053b1f3b 100644
--- a/lib/msun/src/e_lgammaf_r.c
+++ b/lib/msun/src/e_lgammaf_r.c
@@ -132,7 +132,11 @@ __ieee754_lgammaf_r(float x, int *signgamp)
 	*signgamp = 1;
 	ix = hx&0x7fffffff;
 	if(ix>=0x7f800000) return x*x;
-	if(ix==0) return one/vzero;
+	if(ix==0) {
+	    if(hx<0)
+		*signgamp = -1;
+	    return one/vzero;
+	}
 	if(ix<0x35000000) {	/* |x|<2**-21, return -log(|x|) */
 	    if(hx<0) {
 	        *signgamp = -1;