loops - Getting an optimization report from GCC

Question

I would like to know if there is an option I can use with GCC to get a detailed report on the optimization actually chosen and performed by the compiler. This is possible with the Intel C compiler using the -opt-report. I do not want to look at the assembly file and figure out the optimization. I am specifically looking for the loop unrolling and loop tiling factors chosen by the compiler.

Answer 1

Although it's not a report in the sense of aggregated information, you might try the -fdump-ipa-all option which makes gcc produce dump files which at least keep you from having to analyse assembler code on what happened.

Regarding loop optimization the -fdump-rtl-loop2 option might be of interest.

For details on all this please see the section Options for Debugging Your Program or GCC of the manual.