How can I find out which optimizing techniques were used for each function?

[Byoungyoung Lee]

Is there anyway in gcc to log the information about which compiler
options were actually used to optimize each function?
For example, if I compile a program with option -O3, how could I
figure out which specific options (such as -funroll-loops or something
like that) were used to optimize function X ?

- Byoungyoung Lee
-- 
Byoungyoung Lee
HPC Lab., Dept. of Computer Science & Engineering, POSTECH, Pohang
Korea 790-784
Tel: +82-54-279-2915, Mobile: +82-10-9260-6720