In the V5 to V6 compiler migration document is the following with respect to optimzations
-O0 No Optimization. Not recommended for use in ARM Compiler 6.6
-O1 Limited Optimization. This is currently the recommended level for source level debugging.
I would like to know why -O0 is not recommended. I find -O1 has optimizations which affect breakpoints and single-stepping through code in a sane manner.
I hadn't seen that. Thank you.
I find the note saying "The Arm Compiler 5 -O0 option is more similar to the Arm Compiler 6 -O1 option than the Arm Compiler 6 -O0 option." peculiar. It may be the most similar, but I find there to be optimizations enabled that are affecting debugging.
I do not expect the point where I set a breakpoint to be optimized away. This includes setting a breakpoint on a variable and on early returns within a function. Setting the optimization to -O0 makes things work how I expect.
If code size is not an issue and I want to prioritize debugging I shouldn't have to worry about why ARM recommends not using -O0.
I guess that -O0 is very unoptimized - but if it is suitable for your needs, then there is no issue in using it.