diff --git a/src/e_atan2.c b/src/e_atan2.c
index c27b41d..70384dc 100644
--- a/src/e_atan2.c
+++ b/src/e_atan2.c
@@ -71,7 +71,7 @@ __ieee754_atan2(double y, double x)
 	if(((ix|((lx|-lx)>>31))>0x7ff00000)||
 	   ((iy|((ly|-ly)>>31))>0x7ff00000))	/* x or y is NaN */
 	   return x+y;
-	if(((hx-0x3ff00000)|lx)==0) return atan(y);   /* x=1.0 */
+	if(hx==0x3ff00000&&lx==0) return atan(y);   /* x=1.0 */
 	m = ((hy>>31)&1)|((hx>>30)&2);	/* 2*sign(x)+sign(y) */
 
     /* when y = 0 */