Matthew Fortune <matthew.fort...@imgtec.com> writes: >> Matthew Fortune <matthew.fort...@imgtec.com> writes: >> > I'm still interested in how successfully the MIPS backend is managing >> > to avoid floating point but I am also convinced there are bugs in >> > ld.so entry points for MIPS. >> >> It uses the standard mechanism to avoid it, which is marking uses of FP >> registers for integer moves, loads and stores with "*". This tells >> the register >> allocator to ignore those alternatives. AFAIK it is effective and I think >> any >> cases where it doesn't work would be fair bug reports. > > I understand that '*' has no effect on whether reload/LRA will use the > alternative though so I take that to mean they could still allocate FP > regs as part of an integer move?
No, they shouldn't. Admittedly the mechanism for reload is a bit indirect: the GPR alternatives have priority and there is no GPR-and-FPR register class that could be used to sum up separate "d" and "*f" alternatives. It should be effective though. There too I think any case where it didn't work would be a bug. ISTR LRA handles reloads by generating reload pseudos. IMO it should never do that for a '*' class, since that's tantamount to allocating a pseudo to that class. I haven't checked whether LRA enforces that or not though. Thanks, Richard
