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authorJoseph Myers <joseph@codesourcery.com>2012-11-04 19:26:02 +0000
committerJoseph Myers <joseph@codesourcery.com>2012-11-04 19:26:02 +0000
commita0c2940d67e59b2f19515e2ac7280a7be9629ffa (patch)
tree7827ebc10a3baa4a0418e12a2d28c666d0b157bd /sysdeps/ieee754
parentb830319d49a421741b61ae29ce32ab37f8b970ed (diff)
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Fix fma overflow results outside round-to-nearest mode (bug 14797).
Diffstat (limited to 'sysdeps/ieee754')
-rw-r--r--sysdeps/ieee754/dbl-64/s_fma.c9
-rw-r--r--sysdeps/ieee754/ldbl-128/s_fmal.c10
-rw-r--r--sysdeps/ieee754/ldbl-96/s_fmal.c10
3 files changed, 17 insertions, 12 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_fma.c b/sysdeps/ieee754/dbl-64/s_fma.c
index 07fe715617..cd28830709 100644
--- a/sysdeps/ieee754/dbl-64/s_fma.c
+++ b/sysdeps/ieee754/dbl-64/s_fma.c
@@ -55,16 +55,17 @@ __fma (double x, double y, double z)
 	 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 zero, compute as x * y + z.  */
+      /* If x or y or z is Inf/NaN, or if x * y is zero, compute as
+	 x * y + z.  */
       if (u.ieee.exponent == 0x7ff
 	  || v.ieee.exponent == 0x7ff
 	  || w.ieee.exponent == 0x7ff
-	  || u.ieee.exponent + v.ieee.exponent
-	     > 0x7ff + IEEE754_DOUBLE_BIAS
 	  || x == 0
 	  || y == 0)
 	return x * y + z;
+      /* If fma will certainly overflow, compute as x * y.  */
+      if (u.ieee.exponent + v.ieee.exponent > 0x7ff + IEEE754_DOUBLE_BIAS)
+	return x * y;
       /* If x * y is less than 1/4 of DBL_DENORM_MIN, neither the
 	 result nor whether there is underflow depends on its exact
 	 value, only on its sign.  */
diff --git a/sysdeps/ieee754/ldbl-128/s_fmal.c b/sysdeps/ieee754/ldbl-128/s_fmal.c
index d576403b25..6fa663a6c0 100644
--- a/sysdeps/ieee754/ldbl-128/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-128/s_fmal.c
@@ -56,16 +56,18 @@ __fmal (long double x, long double y, long double z)
 	 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 zero, compute as x * y + z.  */
+      /* If x or y or z is Inf/NaN, or if x * y is zero, compute as
+	 x * y + z.  */
       if (u.ieee.exponent == 0x7fff
 	  || v.ieee.exponent == 0x7fff
 	  || w.ieee.exponent == 0x7fff
-	  || u.ieee.exponent + v.ieee.exponent
-	     > 0x7fff + IEEE854_LONG_DOUBLE_BIAS
 	  || x == 0
 	  || y == 0)
 	return x * y + z;
+      /* If fma will certainly overflow, compute as x * y.  */
+      if (u.ieee.exponent + v.ieee.exponent
+	  > 0x7fff + IEEE854_LONG_DOUBLE_BIAS)
+	return x * y;
       /* If x * y is less than 1/4 of LDBL_DENORM_MIN, neither the
 	 result nor whether there is underflow depends on its exact
 	 value, only on its sign.  */
diff --git a/sysdeps/ieee754/ldbl-96/s_fmal.c b/sysdeps/ieee754/ldbl-96/s_fmal.c
index 32e71a18ba..53098b6d4e 100644
--- a/sysdeps/ieee754/ldbl-96/s_fmal.c
+++ b/sysdeps/ieee754/ldbl-96/s_fmal.c
@@ -56,16 +56,18 @@ __fmal (long double x, long double y, long double z)
 	 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 zero, compute as x * y + z.  */
+      /* If x or y or z is Inf/NaN, or if x * y is zero, compute as
+	 x * y + z.  */
       if (u.ieee.exponent == 0x7fff
 	  || v.ieee.exponent == 0x7fff
 	  || w.ieee.exponent == 0x7fff
-	  || u.ieee.exponent + v.ieee.exponent
-	     > 0x7fff + IEEE854_LONG_DOUBLE_BIAS
 	  || x == 0
 	  || y == 0)
 	return x * y + z;
+      /* If fma will certainly overflow, compute as x * y.  */
+      if (u.ieee.exponent + v.ieee.exponent
+	  > 0x7fff + IEEE854_LONG_DOUBLE_BIAS)
+	return x * y;
       /* If x * y is less than 1/4 of LDBL_DENORM_MIN, neither the
 	 result nor whether there is underflow depends on its exact
 	 value, only on its sign.  */