Tom Stellard 57342fb583 GlobalISel: Use a callback to compute constrained reg class for unallocatble registers ...

Summary:
constrainOperandRegClass() currently fails if it tries to constrain the
register class of an operand that is defeined with an unallocatable register
class.  This patch resolves this by adding a target callback to compute
register constriants in this case.

This is required by the AMDGPU because many of its instructions have source opreands
defined with the unallocatable register classe VS_32 which is a union of two allocatable
register classes VGPR_32 and SReg_32.

Reviewers: dsanders, aditya_nandakumar

Reviewed By: aditya_nandakumar

Subscribers: rovka, kristof.beyls, tpr, llvm-commits

Differential Revision: https://reviews.llvm.org/D45991

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331485 91177308-0d34-0410-b5e6-96231b3b80d8

2018-05-03 21:44:16 +00:00

..

llvm

GlobalISel: Use a callback to compute constrained reg class for unallocatble registers

2018-05-03 21:44:16 +00:00

llvm-c

Remove \brief commands from doxygen comments.

2018-05-01 15:54:18 +00:00