ARM CortexM3 Compiler - Optimization

[rajkrishna]

Posted on January 12, 2010 at 05:53

ARM CortexM3 Compiler - Optimization

[rajkrishna]

Posted on May 17, 2011 at 13:37

Any issue with CortexM3 compiling for Zero optimization?

The same code can be run with o1,o2 or o3 but cannot run with o0.

Any hints?

Thnx in advance.

[st3]

Posted on May 17, 2011 at 13:37

There is not just one ''ARM CortexM3 Compiler'' - You need to state which specific compiler and version you are using!

Quote:

The same code can be run with o1,o2 or o3 but cannot run with o0.

It is almost certainly a flaw in your source code; ie, it is relying upon something that it shouldn't, but which just happens not to fail with o1,o2 or o3.

Usually it's the other way around - stuff works for no (or low) optimisation, but fails at higher optimisation.

You need to do some debuggin to determine precisely what is (or is not) happening - ''doesn't run'' tells next to nothing:

Check your use of volatile.

Check for timing issues.

Also check memory alignment issues.

Are you sure that this isn't a symptom of an underlying hardware fault?

[ This message was edited by: st7 on 12-01-2010 10:24 ]