Besides moving structural computations to CodeGenRegisters.cpp, this
also well-defines the order of these lists:
- Sub-register lists come from a pre-order traversal of the graph
defined by the SubRegs lists in the .td files.
- Super-register lists are topologically ordered so no register comes
before any of its sub-registers. When the sub-register graph is not a
tree, independent super-registers appear in numerical order.
- Lists of overlapping registers are ordered according to register
number.
This reverses the order of the super-regs lists, but nobody was
depending on that. The previous order of the overlaps lists was odd, and
it may have depended on the precise behavior of std::stable_sort.
The old computations are still there, but will be removed shortly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132881 91177308-0d34-0410-b5e6-96231b3b80d8
Create a new CodeGenRegBank class that will eventually hold all the code
that computes the register structure from Records.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132849 91177308-0d34-0410-b5e6-96231b3b80d8
I'll be moving some more code there to gather all of the
register-specific stuff in one place. Currently it is shared between
CodeGenTarget and RegisterInfoEmitter.
The plan is that CodeGenRegisters can compute the full register bank
structure while RegisterInfoEmitter only will handle the printing part.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132788 91177308-0d34-0410-b5e6-96231b3b80d8
