cannot use isnan here as need to check for INF as well

kernel/zarch/zscal.c

@@ -339,7 +339,7 @@ int CNAME(BLASLONG n, BLASLONG dummy0, BLASLONG dummy1, FLOAT da_r, FLOAT da_i,
         zscal_kernel_8_zero(n1, x);
       else
         zscal_kernel_8(n1, da_r, da_i, x);
-    else if (da_i == 0 && !isnan(da_r))
+    else if (da_i == 0 && da_r == da_r))
       zscal_kernel_8_zero_i(n1, alpha, x);
     else
       zscal_kernel_8(n1, da_r, da_i, x);