[Bug target/78176] [MIPS] miscompiles ldxc1 with large pointers on 32-bits

[mpf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78176

--- Comment #29 from mpf at gcc dot gnu.org ---
I don't remember the detail of this issue but I believe I was convinced that it
is down to the lack of setting PX appropriately in HW. UX==0, PX==1. The PX
control bit forces address calculations i.e. base + imm or base + reg to be
performed with 32-bit rules but allows 64 instruction usage. Since there is a
processor mode that is perfectly capable of meeting the requirements of a
program with 64bit data and 32bit pointers then the solution is to set PX for
N32 rather than UX.