When an instruction has an encoding definition for only a subset of
the available HwModes, ensure we just avoid generating an encoding
rather than crash.
llvm-svn: 374150
Much like ValueTypeByHwMode/RegInfoByHwMode, this patch allows targets
to modify an instruction's encoding based on HwMode. When the
EncodingInfos field is non-empty the Inst and Size fields of the Instruction
are ignored and taken from EncodingInfos instead.
As part of this promote getHwMode() from TargetSubtargetInfo to MCSubtargetInfo.
This is NFC for all existing targets - new code is generated only if targets
use EncodingByHwMode.
llvm-svn: 372320
James Molloy