Call math_opt_barrier inside if

Since floating-point operation may trigger floating-point exceptions,
we call math_opt_barrier inside if to prevent code motion.

	[BZ #19465]
	* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Call math_opt_barrier
	inside if.
	* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Likewise.
	* sysdeps/ieee754/ldbl-96/s_fma.c (__fma): Likewise.
	* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Likewise.

ChangeLog

@@ -1,3 +1,12 @@
+2016-01-15  H.J. Lu  <hongjiu.lu@intel.com>
+
+	[BZ #19465]
+	* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Call math_opt_barrier
+	inside if.
+	* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Likewise.
+	* sysdeps/ieee754/ldbl-96/s_fma.c (__fma): Likewise.
+	* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Likewise.
+
 2016-01-14  H.J. Lu  <hongjiu.lu@intel.com>
 
 	[BZ #19466]

sysdeps/ieee754/dbl-64/s_fma.c

@@ -175,7 +175,10 @@ __fma (double x, double y, double z)
 
   /* Ensure correct sign of exact 0 + 0.  */
   if (__glibc_unlikely ((x == 0 || y == 0) && z == 0))
-    return x * y + z;
+    {
+      x = math_opt_barrier (x);
+      return x * y + z;
+    }
 
   fenv_t env;
   libc_feholdexcept_setround (&env, FE_TONEAREST);

sysdeps/ieee754/ldbl-128/s_fmal.c

@@ -179,7 +179,10 @@ __fmal (long double x, long double y, long double z)
 
   /* Ensure correct sign of exact 0 + 0.  */
   if (__glibc_unlikely ((x == 0 || y == 0) && z == 0))
-    return x * y + z;
+    {
+      x = math_opt_barrier (x);
+      return x * y + z;
+    }
 
   fenv_t env;
   feholdexcept (&env);

sysdeps/ieee754/ldbl-96/s_fma.c

@@ -41,7 +41,10 @@ __fma (double x, double y, double z)
 
   /* Ensure correct sign of exact 0 + 0.  */
   if (__glibc_unlikely ((x == 0 || y == 0) && z == 0))
-    return x * y + z;
+    {
+      x = math_opt_barrier (x);
+      return x * y + z;
+    }
 
   fenv_t env;
   feholdexcept (&env);

sysdeps/ieee754/ldbl-96/s_fmal.c

@@ -177,7 +177,10 @@ __fmal (long double x, long double y, long double z)
 
   /* Ensure correct sign of exact 0 + 0.  */
   if (__glibc_unlikely ((x == 0 || y == 0) && z == 0))
-    return x * y + z;
+    {
+      x = math_opt_barrier (x);
+      return x * y + z;
+    }
 
   fenv_t env;
   feholdexcept (&env);