Changes

[ARM] Added more patterns to generate SSAT/USAT with shift

Added patterns to generate an SSAT or USAT with shift for
SSAT/USAT instructions that are matched from IR patterns.

Differential Revision: https://reviews.llvm.org/D88145

[llvm] Fix unused variable in non-debug configurations

[ARM][LowOverheadLoops] Cleanup and re-arrange

Rename and reorganise how we decide where to put the LoopStart
instruction.

[AMDGPU] Reformat AMDGPUTargetLowering::isSDNodeAlwaysUniform. NFC.

[clang][codegen] Annotate `correctly-rounded-divide-sqrt-fp-math` fn-attr for OpenCL only.

- `-cl-fp32-correctly-rounded-divide-sqrt` is an OpenCL-specific option
  and `correctly-rounded-divide-sqrt-fp-math` should be added for OpenCL
  at most.

Differential revision: https://reviews.llvm.org/D88303

Revert "Add the ability to write target stop-hooks using the ScriptInterpreter."

This temporarily reverts commit b65966cff65bfb66de59621347ffd97238d3f645
while Jim figures out why the test is failing on the bots.

[clangd] Add a trained DecisionForest for code completion.

Replaces the dummy CodeCompletion model with a trained DecisionForest
model.
The features.json needs to be manually curated specifying the features
to be used. This is a one-time cost and does not change if the model
changes until we decide to add/remove features.

Differential Revision: https://reviews.llvm.org/D88071

[ubsan] nullability-arg: Fix crash on C++ member pointers

Extend -fsanitize=nullability-arg to handle call sites which accept C++
member pointers.

rdar://62476022

Differential Revision: https://reviews.llvm.org/D88336

[unittests] Preserve LD_LIBRARY_PATH in crash recovery test

We need to preserve the LD_LIBRARY_PATH environment variable when
spawning a child process (certain setups rely on non-standard paths
for e.g. libstdc++). In order to achieve this, set
LLVM_CRC_UNIXCRCRETURNCODE in the parent process instead of creating
the child's environment from scratch.

Reviewed By: aganea

Differential Revision: https://reviews.llvm.org/D88308

[AArch64] Reuse map iterator instead of double lookup. NFC

Add FunctionType to MLIR C and Python bindings.

Differential Revision: https://reviews.llvm.org/D88416

[clangd] Use Decision Forest to score code completions.

By default clangd will score a code completion item using heuristics model.

Scoring can be done by Decision Forest model by passing `--ranking_model=decision_forest` to
clangd.

Features omitted from the model:
- `NameMatch` is excluded because the final score must be multiplicative in `NameMatch` to allow rescoring by the editor.
- `NeedsFixIts` is excluded because the generating dataset that needs 'fixits' is non-trivial.

There are multiple ways (heuristics) to combine the above two features with the prediction of the DF:
- `NeedsFixIts` is used as is with a penalty of `0.5`.

Various alternatives of combining NameMatch `N` and Decision forest Prediction `P`
- N * scale(P, 0, 1): Linearly scale the output of model to range [0, 1]
- N * a^P:
  - More natural: Prediction of each Decision Tree can be considered as a multiplicative boost (like NameMatch)
  - Ordering is independent of the absolute value of P. Order of two items is proportional to `a^{difference in model prediction score}`. Higher `a` gives higher weightage to model output as compared to NameMatch score.

Baseline MRR = 0.619
MRR for various combinations:
N * P = 0.6346, advantage%=2.5768
N * 1.1^P = 0.6600, advantage%=6.6853
N * **1.2**^P = 0.6669, advantage%=**7.8005**
N * **1.3**^P = 0.6668, advantage%=**7.7795**
N * **1.4**^P = 0.6659, advantage%=**7.6270**
N * 1.5^P = 0.6646, advantage%=7.4200
N * 1.6^P = 0.6636, advantage%=7.2671
N * 1.7^P = 0.6629, advantage%=7.1450
N * 2^P = 0.6612, advantage%=6.8673
N * 2.5^P = 0.6598, advantage%=6.6491
N * 3^P = 0.6590, advantage%=6.5242
N * scaled[0, 1] = 0.6465, advantage%=4.5054

Differential Revision: https://reviews.llvm.org/D88281

[InstCombine] Add basic trunc(shr(trunc(x),c)) tests

Helps improve the minor regressions noticed on D88316

[GlobalISel] Combine (xor (and x, y), y) -> (and (not x), y)

When we see this:

```
%and = G_AND %x, %y
%xor = G_XOR %and, %y
```

Produce this:

```
%not = G_XOR %x, -1
%new_and = G_AND %not, %y
```

as long as we are guaranteed to eliminate the original G_AND.

Also matches all commuted forms. E.g.

```
%and = G_AND %y, %x
%xor = G_XOR %y, %and
```

will be matched as well.

Differential Revision: https://reviews.llvm.org/D88104

[AArch64][GlobalISel] Support shifted register form in emitTST

Support emitting ANDSXrs and ANDSWrs in `emitTST`. Update opt-fold-compare.mir
to show that it works.

Differential Revision: https://reviews.llvm.org/D87530

[CostModel] split handling of intrinsics from other calls

This should be close to NFC (no-functional-change), but I
can't completely rule out that some call on some target
travels down a different path. There's an especially large
amount of code spaghetti in this part of the cost model.

The goal is to clean up the intrinsic cost handling so
we can canonicalize to the new min/max intrinsics without
causing regressions.