This allows the processor-specific machine model to override selected
base opcodes without any fanciness.
e.g. InstRW<[CoreXWriteVANDP], (instregex "VANDP")>.
llvm-svn: 165180
A processor can now arbitrarily alias one SchedWrite onto
another. Only the SchedAlias definition need be within the processor
model. The aliased SchedWrite may be a SchedVariant, WriteSequence, or
transitively refer to another alias.
llvm-svn: 165179
subtarget CPU descriptions and support new features of
MachineScheduler.
MachineModel has three categories of data:
1) Basic properties for coarse grained instruction cost model.
2) Scheduler Read/Write resources for simple per-opcode and operand cost model (TBD).
3) Instruction itineraties for detailed per-cycle reservation tables.
These will all live side-by-side. Any subtarget can use any
combination of them. Instruction itineraries will not change in the
near term. In the long run, I expect them to only be relevant for
in-order VLIW machines that have complex contraints and require a
precise scheduling/bundling model. Once itineraries are only actively
used by VLIW-ish targets, they could be replaced by something more
appropriate for those targets.
This tablegen backend rewrite sets things up for introducing
MachineModel type #2: per opcode/operand cost model.
llvm-svn: 159891