It’s clear to me now. After reading through the optimization section again, I can see more of the meaning; perhaps because I am looking for it. Thank you for taking the time to answer. David From: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx<mailto:segher@xxxxxxxxxxxxxxxxxxx>> Date: Monday, Mar 16, 2020, 6:36 PM To: Shrader, David Lee <dshrader@xxxxxxxx<mailto:dshrader@xxxxxxxx>> Cc: gcc-help@xxxxxxxxxxx <gcc-help@xxxxxxxxxxx<mailto:gcc-help@xxxxxxxxxxx>> Subject: Re: [EXTERNAL] Re: question about knowing when optimization options are used Hi! On Mon, Mar 16, 2020 at 11:55:01PM +0000, Shrader, David Lee wrote: > Thank you for the reply. So, what you're saying is that the output of `gcc -Q --help=optimizers` doesn't necessarily reflect what optimization gcc is going to do when -O0 is being used, correct? This is because no (or very little) optimization is actually allowed to be done when -O0 is use. Yes. Some of the documentation isn't clear on this, but in context it should be clear? Segher
