Impact of compiler warning message

["Min-Chia Jiang" <jmc@xxxxxxxxxxxxxxxxxxxxxx>]

Hi there,

Can anyone advise me, what is the impact of those Warning messages shown 
while compiling?
Do warning messages have any effect to the program?
For example, will more warning messages cause larger image/object size, or 
reduce the performance of compiler?
 
Best Regards
M.C Jiang