On 02/25/2016 04:40 PM, Andrew Haley wrote: > On 02/25/2016 03:36 PM, Matthias Pfaller wrote: >> When gcc decides to inline mrsbasepri it will again be free to CSE the >> mrs instructions :-(. Is it really just me having run into this problem? >> How do other people solve the problem that __asm__ without input is >> handled like a __attribute((const)) function? > > Either with a memoryclobber, or make it volatile, or both. I have a memoryclobber, but that's output and doesn't help for input. And marking it volatile will avoid deleting it in all cases. But I want to get it deleted when I don't need the return value. Its just getting deleted by CSE I want to avoid. That's because I sometimes need dfi(); ... some code ... efi(); and sometimes I'd like to do sr = dfi(); ... some code ... rfi(sr); In the first case I'd like gcc to delete the "mrs Rx,basepri". In the second case I need it. Usually that works quite well, but when you do multiple sr = dfi(); ... rfi(sr) sequences in a function, gcc will CSE the later mrs opcodes. With the __COUNTER__ trick I can avoid that. But when you are using this in functions that get inlined you're off where you started... regards, Matthias -- Matthias Pfaller Software Entwicklung marco Systemanalyse und Entwicklung GmbH Tel +49 8131 5161 41 Hans-Böckler-Str. 2, D 85221 Dachau Fax +49 8131 5161 66 http://www.marco.de/ Email leo@xxxxxxxx Geschäftsführer Martin Reuter HRB 171775 Amtsgericht München
