If you run cmake without pexpect installed it errors as expected.
However, if you just `pip install pexpect` and cmake again it still
doesn't find it because it cached the result of the search.

Unset the result before looking for pexpect. So that this works
as expected:
cmake ...
pip3 install pexpect
cmake ...

* Leverage TableGen record descriptions of LLVM or DirectX intrinsics
that can be directly mapped in DXIL Ops TableGen description. As a
result, such DXIL Ops can be succinctly described without duplication.
DXILEmitter backend can derive the properties of DXIL Ops accordingly.
* Ensured that corresponding lit tests pass.

Adds diagnostics for lambda expressions being cast to boolean values,
which results in the expression always evaluating to true.
Earlier, Clang allowed compilation of such erroneous programs, but now
emits a warning through `-Wpointer-bool-conversion`.

Fixes #82512 

Compute Constructs do not permit jumping in/out of them, so this patch
implements this for 'goto' as a followup to the other patches that have
done the same thing.

It does this by modifying the JumpDiagnostics to work with this, plus
setting the function to needing jump diagnostics if we discover a goto
or label inside of a Compute Construct.

Add the SignReturnAddressScopeKind to the BranchProtectionInfo class.

Removing debug-intrinsics requires that we always insert with an
iterator, not with an instruction position. To enforce that, we need to
eliminate the `Instruction *` taking functions. It's safe to leave the
insert-at-end-of-block functions as the intention is clear for debug
info purposes (i.e., insert after both instructions and debug-info at
the end of the function).

This patch demonstrates how that needs to happen. At a variety of
call-sites to the `CreateNeg` constructor we need to consider:
* Has this instruction been selected because of the operation it
performs? In that case, just call `getIterator` and pass an iterator in.
* Has this instruction been selected because of it's position? If so, we
need to keep the iterator identifying that position (see the 3rd hunk
changing Reassociate.cpp, although it's coincidentally not debug-info
significant).

This also demonstrates what we'll try and do with the constructor
methods going forwards: have one fully explicit set of parameters
including iterator, and another with default-arguments where the
block-to-insert-into argument defaults to nullptr / no-position,
creating an instruction that hasn't been inserted yet.

Basic implementation of lane mask merging for GlobalISel.
Lane masks on GlobalISel are registers with sgpr register class
and S1 LLT - required by machine uniformity analysis.
Implements equivalent of lowerPhis from SILowerI1Copies.cpp in:
patch 1: https://github.com/llvm/llvm-project/pull/75340
patch 2: https://github.com/llvm/llvm-project/pull/75349
patch 3: https://github.com/llvm/llvm-project/pull/80003
patch 4: https://github.com/llvm/llvm-project/pull/78431
patch 5: is in this commit:

AMDGPU/GlobalISelDivergenceLowering: constrain incoming registers

Previously, in PHIs that represent lane masks, incoming registers
taken as-is were not selected as lane masks. Such registers are not
being merged with another lane mask and most often only have S1 LLT.
Implement constrainAsLaneMask by constraining incoming registers
taken as-is with lane mask attributes, essentially transforming them
to lane masks. This is final step in having PHI instructions created
in this pass to be fully instruction-selected.

This extends the known bits for extending loads which have range
metadata, handling the range metadata on the original memory type,
extending that to the correct BitWidth.

Summary:
These hacks can be removed now that
https://github.com/llvm/llvm-project/pull/83376 fixed the underlying
problem.

getBlockInMask now simply returns an already computed mask, hence
there's no need to adjust the builder insert point.

Allows us to peek through the F16 conversion nodes, mainly to simplify shuffles

An easy part of #83414

This came up on Discourse.

See:
https://discourse.llvm.org/t/module-verification-failed-instruction-does-not-dominate-all-uses/77207/

Following on from #83118, this adds aliases for the "rtn" forms of these
instructions. The fact that they were missing from SP3 was an oversight
which has been fixed now.

This reverts commit f0484e08.

Reason: Broke the sanitizer build bots. See the github comments on
https://github.com/llvm/llvm-project/commit/f0484e08bdcf64106592808e3ca80404937b4657
for more information

Some MIR and IR tests include checks for register class IDs, which are
unnecessary since the register class name is also checked for and that
doesn't change when new classes are added. This patch replaces the
hard-coded register class ID checks with regexes so they don't have to
be updated every time a new class is added.

it changes behaviour for debug vs release builds.

Follow the 2019 rules and order -0 as less than +0 and +0 as greater
than -0. As currently defined this isn't required for the intrinsics,
but is a better QoI.

This will avoid the workaround in libc added by #83158

Missed adding a . in the test check

[X86] getFauxShuffleMask - handle insert_vector_elt(bitcast(extract_vector_elt(x))) shuffle patterns

If the bitcast is between types of equal scalar size (i.e. fp<->int bitcasts), then we can safely peek through them

Fixes #83289

expand-arith-ops.mlir fails on windows, but this is unrelated to this PR

This reverts commit 634b0243.

Failing EXPENSIVE_CHECKS builds with "undefined physical register".

We weren't checking to see if the partial_path was empty before adding
completions and this led to crashes when the class object and a variable
both start with the same substring.

Fixes [#81536](https://github.com/llvm/llvm-project/issues/81536

)

---------

Co-authored-by: Michael Buch <michaelbuch12@gmail.com>

Preliminary patch for https://github.com/llvm/llvm-project/pull/83285 to
turn polymorphism on by default.

Will give a few days warning for people to remove the flag from their
workflow using flang-new.

Also easier to revert if issues with the gfortran test suites.

Picolibc does not provide the clock_gettime function nor the "rt" library.
check_library_exists was invalidly detecting the "rt" library due to cmake issue 
present, when cross-compiling[1]. This resulted with "chrono.cpp" trying to link
to the "rt" library and following error:
    unable to find library from dependent library specifier: rt

[1] https://gitlab.kitware.com/cmake/cmake/-/issues/18121

- Make `andi` cost 1 in SK_Broadcast
- Query the cost of VID_V, VRSUB_VX/VRSUB_VI which would scale with LMUL

This patch fixes the #67002 ([OpenMP][Clang] Scan Directive not
supported for Generic types). It disables the Sema checks/analysis that
are run on the helper arrays which go into the implementation of the
`omp scan` directive until the template instantiation happens.
Grateful to @alexey-bataev for suggesting these changes.

Modifying clang/lib/CodeGen/CGStmtOpenMP.cpp to accept multiple `init`
clauses with `interop` directive.

---------

Co-authored-by: Sunil Kuravinakop

Document that we don't use the double compare and swap instructions due
to ABI concerns.

Also combine (X != 0) | (Y != 0) -> (X | Y) != 0

This reverts commit 79330098 as pexpect
is not available on any of the GreenDragon bots.