src/glsl/builtins/ir/noise1

((function noise1
   (signature float
     (parameters
       (declare (in) float x))
     ((return (expression float noise (var_ref x)))))
   (signature float
     (parameters
       (declare (in) vec2 x))
     ((return (expression float noise (var_ref x)))))
   (signature float
     (parameters
       (declare (in) vec3 x))
     ((return (expression float noise (var_ref x)))))
   (signature float
     (parameters
       (declare (in) vec4 x))
     ((return (expression float noise (var_ref x)))))
))