The armv7 distro bootstrap have run into a number of packages failing to compile in Thumb mode (default enabled in rpmrc) failing on ARM assembly parts with conditional branch instructions. In thumb mode one apparently need to use the IT instruction to hint to the CPU about the conditions of following instructions in addition to have the conditions on the instructions themselves. While investing these I saw rumors about GCC eventually adding an automatic handling of these adding IT instructions as needed, and even projects being very reluctant about touching any of this until GCC have made up it's mind, and finally in an upstream bug report on pulseaudio there is a reference to the -mimplicit-it=thumb GAS option doing exacly this. Is there any drawbacks from enabling implicit IT instruction generation letting GAS automatically deal with this as required by Thumb mode? If not, should we add this to rpmrc? -Wa, -mimplicit-it=thumb from what I can understand it should be quite safe. And I am even of the opinion that GAS is way better suited at adding these instructions than the average programmer as it carries redundant information which need to match the conditions of the instructions following after. Would even argue that it's a design error in Thumb assembly language to even require the instruction to be declared not have the instruction implicitly generated by default based on the conditional instructions it covers. Programmers are humans. But that is a separate topic. Regards Henrik _______________________________________________ arm mailing list arm@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/arm
