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Diffstat (limited to 'sysdeps/ieee754/ldbl-128/s_fmal.c')
-rw-r--r--sysdeps/ieee754/ldbl-128/s_fmal.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128/s_fmal.c b/sysdeps/ieee754/ldbl-128/s_fmal.c
index df68ade435..46b3d81ce5 100644
--- a/sysdeps/ieee754/ldbl-128/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-128/s_fmal.c
@@ -50,6 +50,11 @@ __fmal (long double x, long double y, long double z)
 	  && u.ieee.exponent != 0x7fff
           && v.ieee.exponent != 0x7fff)
 	return (z + x) + y;
+      /* If z is zero and x are y are nonzero, compute the result
+	 as x * y to avoid the wrong sign of a zero result if x * y
+	 underflows to 0.  */
+      if (z == 0 && x != 0 && y != 0)
+	return x * y;
       /* If x or y or z is Inf/NaN, or if fma will certainly overflow,
 	 or if x * y is less than half of LDBL_DENORM_MIN,
 	 compute as x * y + z.  */