Loop blocking optimization

[Ashwath Kumar Chandrasekaran]

Hello,

I would like to use the loop blocking optimization provided by the
flag -floop-block.

I tried this command for compiling

command 1: gcc -O1 -S test.c -o output1.s
command 2: gcc -O1 -fverbose-asm -floop-block -S test.c -o output2.s

I compared output1.s and output2.s but found no difference. I used
simple matrix multiplication program.

I am using GCC 4.8.1. I built it with cloog 0.18.0 and isl 0.11.1.

Do I need to additional flags during compilation for the loop blocking to work?

Please help.

Thanks and Regards,

Ashwath.