[Bug target/64953] Compiling sourcecode for STM32F103 causes USB errors with some optimization settings

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64953

--- Comment #4 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Ok, thanks.

Now please attach the preprocessed source of that file (by adding
--save-temps to the compiler invocation). Also post the exact
command line you use to compile that file. 
Maybe something obvious will show up.