cycleBitsShader = (ctx, qubitSpan, shiftAmount) =>
    CYCLE_SHADER.withArgs(
        ...ketArgs(ctx, qubitSpan),
        WglArg.float("amount", 1 << Util.properMod(-shiftAmount, qubitSpan)))
@param {!CircuitEvalContext} ctx
@param {!int} qubitSpan
@param {!int} shiftAmount
@returns {!WglConfiguredShader}