Hi Ranjith, I don't have an answer to your inquiry, but here's a helpful trick to answer the "Hmmm, I wonder what flags are controlled by the optimization level flags?" ... echo '' | g++ -fverbose-asm -S -x c++ - -o blank.s echo '' | g++ -O0 -fverbose-asm -S -x c++ - -o O0.s echo '' | g++ -O1 -fverbose-asm -S -x c++ - -o O1.s echo '' | g++ -O2 -fverbose-asm -S -x c++ - -o O2.s echo '' | g++ -O3 -fverbose-asm -S -x c++ - -o O3.s echo '' | g++ -Os -fverbose-asm -S -x c++ - -o Os.s Note: there are optimizations above-and-beyond the ones that are identifiable by a specific named flag. HTH, --Eljay
