gistfile1.txt

CREATE INDEX whatever ON dbo.Users(Reputation);
GO 

ALTER FUNCTION dbo.BeatIt(@Reputation INT)
RETURNS TABLE
AS 
RETURN
    SELECT *
    FROM dbo.Users AS u
    WHERE u.Reputation = @Reputation;
GO 

ALTER PROCEDURE dbo.BeatThat(@Reputation INT)
AS
SET NOCOUNT, XACT_ABORT ON;
BEGIN
    DECLARE @ReputationFix INT;
    SET @ReputationFix = @Reputation;
    IF @ReputationFix NOT BETWEEN 1 AND 2000000
    BEGIN
        SET @ReputationFix = 1;
    END
    
    SELECT *
    FROM dbo.BeatIt(@ReputationFix) AS bi;
END;

EXEC dbo.BeatThat @Reputation = 1;

EXEC dbo.BeatThat @Reputation = 2;

DBCC FREEPROCCACHE;