Avoids regression which caused the revert 6d5f87fc42.

This is a hack on a hack. We currently have isUniformMMO,
which improperly treats unknown source value as known uniform.
This is hack from before we had divergence information in the
DAG, and should be removed. This is the minimum change to avoid
the regression; removing the aggressive handling of the unknown
case (or dropping isUniformMMO entirely) are more involved fixes.

This was never constructed and only provided one static helper
function.

Some opcodes in generic MIR represent calls to intrinsics, where the intrinsic
ID is the first non-def operand to the instruction. These are now represented as
a subclass of GenericMachineInstr, and the method MachineInstr::getIntrinsicID()
is now moved to this subclass GIntrinsic.

Some target-defined instructions behave like GMIR intrinsics, and have an
Intrinsic::ID operand. But they should not be recognized as generic intrinsics,
and should not use GIntrinsic::getIntrinsicID(). Separated these out by
introducing a new AMDGPU::getIntrinsicID().

Reviewed By: arsenm, Pierre-vh

Differential Revision: https://reviews.llvm.org/D155556

This restores commit baa3386edb11a2f9bcadda8cf58d56f3707c39fa.
Originally reverted in d0f7850b01cf17e50a4f4b00e3b84dded94df6b8.

This reverts commit baa3386edb11a2f9bcadda8cf58d56f3707c39fa.

The changes did not cover all occurrences of the deteleted function
MachineInstr::getIntrinsicID().

Some opcodes in generic MIR represent calls to intrinsics, where the intrinsic
ID is the first non-def operand to the instruction. These are now represented as
a subclass of GenericMachineInstr, and the method MachineInstr::getIntrinsicID()
is now moved to this subclass GIntrinsic.

Some target-defined instructions behave like GMIR intrinsics, and have an
Intrinsic::ID operand. But they should not be recognized as generic intrinsics,
and should not use GIntrinsic::getIntrinsicID(). Separated these out by
introducing a new AMDGPU::getIntrinsicID().

Reviewed By: arsenm, Pierre-vh

Differential Revision: https://reviews.llvm.org/D155556

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D93813

R600 and GCN do not have anything in common in terms of register
file organization anymore.

Differential Revision: https://reviews.llvm.org/D74426

to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

Summary:
This is a follow-up to r335942.
- Merge SISubtarget into AMDGPUSubtarget and rename to GCNSubtarget
- Rename AMDGPUCommonSubtarget to AMDGPUSubtarget
- Merge R600Subtarget::Generation and GCNSubtarget::Generation into
  AMDGPUSubtarget::Generation.

Reviewers: arsenm, jvesely

Subscribers: kzhuravl, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D49037

llvm-svn: 336851