Add per-property has<Prop>/set<Prop>/reset<Prop> functions to
MachineFunctionProperties.

This adds a GISelValueTrackingPrinterPass that can print the known bits
and sign bit of each def in a function. It is built on the new pass
manager and so adds a NPM GISelValueTrackingAnalysis, renaming the older
class to GISelValueTrackingAnalysisLegacy.

The first 2 functions from the AArch64GISelMITest are ported over to an
mir test to show it working. It also runs successfully on all files in
llvm/test/CodeGen/AArch64/GlobalISel/*.mir that are not invalid. It can
hopefully be used to test GlobalISel known bits analysis more directly
in common cases, without jumping through the hoops that the C++ tests
requires.

- rename `GISelKnownBits` to `GISelValueTracking` to analyze more than
just `KnownBits` in the future

Identified with misc-include-cleaner.

The main difference is that it's possible for multiple change observers
to be installed at the same time whereas there can only be one
MachineFunction delegate installed. This allows downstream targets to
continue to use observers to recursively select. The target in question
was selecting a gMIR instruction to a machine instruction plus some gMIR
around it and relying on observers to ensure it correctly selected any
gMIR it created before returning to the main loop.

See https://discourse.llvm.org/t/rfc-globalisel-instructionselect-allow-arbitrary-instruction-erasure

- Allow customizing instruction-select pass to add additional analysis
  dependencies.

Reviewers: aemerson, arsenm, aeubanks

Reviewed By: arsenm

Pull Request: https://github.com/llvm/llvm-project/pull/95724

RegisterBank Selection for scalable vector G_ADD and G_SUB by creating
new mappings for different types of vector register banks.
Then implement Instruction Selection for the same operations by choosing
the correct RISC-V vector register class.

Add a debug counter that allows forcing an sdag fallback after a certain
number of functions.

The intended use-case is to bisect which function gets miscompiled by
global isel using `-debug-counter=globalisel-count=N` (in cases where
sdag doesn't also miscompile it, of course).

The "falling back" debug line is printed unconditionally, because using
`-debug-only` is usually too spammy for the intended purpose.

G_GLOBAL_VALUE should be lowered into an absolute address if
`-codemodel=small` is used or into a PC-relative if `-codemodel=medium`
is used.

PR #68380 tried to create special instructions to do this, but I don't
see why we need to do that.