Changes

[SCEV] Add more tests using info from loop guards for BTC.

[libc++] Initial support for pre-commit CI with Buildkite

This commit adds basic files and scripts that are used for the Buildkite
pre-commit CI setup. This was tested to mostly work on a fork of llvm-project,
however some adjustments will have to be made as we complete the real
setup.

[SCEV] Extract code to collect conditions to lambda (NFC).

This makes re-using the common functionality easier in follow-up
patches.

Typo fix; NFC

[InstCombine] Add 'partial' bswap tests from PR39793

Tests for basic zext(bswap(trunc(x))) patterns shown on PR39793

Fix some of the more egregious 80-col and whitespace issues; NFC

[InstCombine] Add some extra bswap tests from PR39793

Also test for cases where recognizeBSwapOrBitReverseIdiom checks for a truncated bswap pattern.

[PowerPC][NFC] Merged two switch entries.

Two switch entries did exactly the same thing. This patch merges them.

[SCEV] Swap operands if LHS is not unknown.

Currently we only use information from guards for unknown expressions.
Swap LHS/RHS and predicate, if LHS is not unknown.

[AIX] Try to not use LLVM tools while building runtimes

Since 64-bit XCOFF and the big AR format is not yet supported in some of these tools, this patch avoids additional setup of these tools. This patch is not intended to prevent picking up the LLVM tools if they happen to be available otherwise.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D85329

[SVE] Lower fixed length VECREDUCE_[SMAX|SMIN] to Scalable

This patch is pretty similar to the VECREDUCE_ADD patch, with some minor tweaks.

Results from the AArch64ISD::[SMAX|SMIN]V_PRED return element sized results. This requires an ANY_EXTEND for results < 32-bits, since Legalization promotes those results.

There is no NEON i64 vector support for SMAXV|SMINV, so use SVE for those.

Differential Revision: https://reviews.llvm.org/D88259

[SVE] Revert accidental change from 405e22fbe8719cff6c40eec15c2044f42527f116

Accidentally commited two lines that were not intended. Remove those.

Add a verifier check that rejects non-distinct DISubprogram function
attachments. They would crash the backend, which expects all
DISubprograms that are not part of the type system to have a unit field.

Clang right before https://reviews.llvm.org/D79967 would generate this
kind of broken IR.

rdar://problem/69534688

[NFC] Fix minor typos in comments and reuse concreteOp.

Differential Revision: https://reviews.llvm.org/D88242

[NFC] Fix syntax of ranked memrefs in the MLIR Language Reference.

- Eliminate incorrect |
- Eliminate memspace0 as the memory spaces currently are integer literals and memory
  space 0 is not explicitly printed.

Differential Revision: https://reviews.llvm.org/D88171

[libc++][ci] Don't require passing --token to phabricator-report

The CONDUIT_TOKEN is already taken from the environment. Also, disable
reporting back to Phabricator for now until we're ready to start spamming
the results back. This still needs a bit of testing.