This was initiated from the uses of MCRegUnitIterator, so while likely
not exhaustive, it's a step forward.

Differential Revision: https://reviews.llvm.org/D89975

This separates the two concerns - encapsulation of traversal order; and
iteration.

Differential Revision: https://reviews.llvm.org/D88256

Added unittests. In the process, separated core construction - which just
needs the hits, order, and 'HardHints' values - from construction from
current register allocation state, to simplify testing.

Differential Revision: https://reviews.llvm.org/D88455

Differential Revision: https://reviews.llvm.org/D88197

We only require to include MCRegister.h and SmallVector.h.

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

* The method getRegAllocationHints() is now of bool type instead of void. If
true is returned, regalloc (AllocationOrder) will *only* try to allocate the
hints, as opposed to merely trying them before non-hinted registers.

* TargetRegisterInfo::getRegAllocationHints() is implemented for SystemZ with
an increase in number of LOCRs.

In this case, it is desired to force the hints even though there is a slight
increase in spilling, because if a non-hinted register would be allocated,
the LOCRMux pseudo would have to be expanded with a jump sequence. The LOCR
(Load On Condition) SystemZ instruction must have both operands in either the
low or high part of the 64 bit register.

Reviewers: Quentin Colombet and Ulrich Weigand
https://reviews.llvm.org/D36795

llvm-svn: 317879

If the result of the find is only used to compare against end(), just
use is_contained instead.

No functionality change is intended.

llvm-svn: 278433