[require]
GLSL >= 1.10

[vertex shader]
void main()
{
	gl_Position = gl_Vertex;
}

[fragment shader]
uniform vec4 color;
void main()
{
	/* Test for a bug in the Mesa IR optimizer where source
	 * register values for arithmetic ops were considered based on
	 * a destination channel count basis rather than the positions
	 * of the channels in the writemask.
	 */
	gl_FragColor.xzw = vec3(0.0);
	gl_FragColor.y = color.w + color.y;
}

[test]
uniform vec4 color 0.0 1.0 0.0 0.0
draw rect -1 -1 2 2
probe rgb 1 1 0.0 1.0 0.0