https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64722
--- Comment #9 from David Malcolm <dmalcolm at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #5) > Can you explain it? Usually when this function is called, > pic_offset_table_rtx is NULL and your i386.h macro relies on that. > When initializing default target during initialization it is NULL of course, > and apparently even in target_reinit, when it is called with freshly cleared > heap object for the non-default target. > It is just when jit calls the initialization again without clearing all the > variables... Indeed: I believe the issue here is specifically with the JIT, which is re-running the compiler multiple times in-process, and in particular, is re-running init_emit_regs. > So I believe my proposed change is correct. Agreed, fwiw. > In any case, perhaps jit shouldn't reinitialize everything all the time, at > least if the compilation options don't change. Ideally, yes. Currently the out-of-process invocation of the driver (and thus collect2) dominates the profile, and fixing that is probably GCC 6 material. I've tried hacking it out to directly invoke "as" and "ld", and after fixing that, the per-compilation RTL reinit does show up significantly in the profile, but that probably ought to be tracked as a separate bug. I suspect that avoiding re-initing RTL may have to wait for gcc 6. In the meantime your patch from comment #3 seems a suitable workaround; thanks. I'll attempt a bootstrap with it.
