[LLVMdev] Conceptual difference between "Unallocatable" and "Reserved" registers.
lei.mou.uu at gmail.com
Tue Apr 17 23:09:15 CDT 2012
I'm writing to ask the differences between a "reserved" register and an
"unallocable" register. In X86 backend, for example, the stack pointer
register and instruction pointer are reserved but allocatable. In the
Doxygen document of function llvm::TargetRegisterInfo::getReservedRegs,
it says that a reserved register is one that *has particular uses and
should be considered unavailable at all times. *If it is unavailable at all
times, why not make such a reserved register unallocatable? Thanks!
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the LLVMdev