Yesterday, one of the issues the libc++ builders encountered was that
they were using a client that was too old; too old to even update
automatically.

To get things working, i had to push a testing image with this change.
The testing image has been working for 12 hours now, so it's time to
commit to it :-)

This reverts commit 530f0e64 because it breaks
downstream.

This folds fixed-size vector.shuffle ops that perform a 1-D interleave
to a vector.interleave operation.

For example:

```mlir
%0 = vector.shuffle %a, %b [0, 2, 1, 4] : vector<2xi32>, vector<2xi32>
```

folds to:

```mlir
%0 = vector.interleave %a, %b : vector<2xi32>
```

Depends on: #80967

In presence of symbols with AssocEntityDetails in an expression,
`Traverse`, `AnyTraverse`, `AllTraverse`, and `SetTraverse`
automatically visit the selector expression or variable.

This is most often the desired behavior but can be surprising, and was
not correct for FindImpureCall and HasVectorSubscript.

Add a default template option to flag the behavior to someone willing to
use the Traverse helper for a new utility, and set this template to
false for FindImpureCall and HasVectorSubscript.

This is another follow-up of #83004, which fixed a bug due to some
macros not being defined in some situations. By raising warnings on
undefined macros, this kind of bug is less likely to be introduced.
Similar to #83004, the fix is probably adding an include to
`mlir-config.h` (and potentially defining the macro there).

This is another follow-up of #83004, which made the same change for
`MLIR_CUDA_CONVERSIONS_ENABLED`. As the previous PR, this PR commit
exposes mentioned CMake variable through `mlir-config.h` and uses the
macro that is introduced with the same name. This replaces the macro
`MLIR_NVPTXCOMPILER_ENABLED`, which the CMake files previously defined
manually.

This is another follow-up of #83004, which made the same change for
`MLIR_CUDA_CONVERSIONS_ENABLED`. As the previous PR, this PR commit
exposes mentioned CMake variable through `mlir-config.h` and uses the
macro that is introduced with the same name. This replaces the macro
`MLIR_ENABLE_DEPRECATED_GPU_SERIALIZATION`, which the CMake files
previously defined manually.

Fixes #73764

With this patch, now all the callbacks are demonstrated here.

https://github.com/llvm/llvm-project/issues/83775 shows llvm-mca hits
sanitizer error in cycleEnd. There was an instruction that takes
multiple cycles to issue and is finished executing directly after issue.
Prior to this patch, the instruction is retired on the first issue
cycle, despite taking multiple cycles to issue.

To fix this, if an instruction takes multiple cycles to issue and is
done executing after issue, let updateCarriedOver retire the instruction
when it is fully issued.

Fixes several minor formatting issues and omissions I introduced on the
status pages in previous patches.

Adds custom lowering for tconstpool.

Please ref: https://github.com/llvm/llvm-project/pull/73668 for test
coverage

Make it use and refer to `emitc.yield` and also fix type issues.

And escape the @ in my email

When ldp-aligned-only/stp-aligned-only is specified, modified to cancel
ldp/stp transformation if MachineMemOperand is not present or the access
size is unknown.
In the previous implementation, the test passed when there was no
MachineMemOperand. Also, if the size was unknown, an incorrect value was
used or an assertion failed. (But actually, if there is no
MachineMemOperand, it will be excluded from the target by
isCandidateToMergeOrPair() before reaching the part.)

A statistic NumFailedAlignmentCheck is added. NumPairCreated is modified
so that it only counts if it is not canceled.

`va_list` is a platform-specific type. On some, it is a struct instead
of a pointer to a struct, so `lookupFn` was ignoring calls to `vfprintf`
and `vfscanf`.

`stream.c` now runs in four different platforms to make sure the logic
works across targets.

This patch fixes #71698. It allows defining the default target version
prior to other version definitions without raising semantic errors.

For an uninformed user, the error message might refer to a missing "TSan
stopping operation", rather than indicating that TSan is missing **and
therefore** operation is stopped.

This patch regroups declarations in `Sema` based on the file they are
implemented in (e.g. `SemaChecking.cpp`). This allows to logically split
`Sema` in 42 groups. No physical separation is done (e.g. splitting
`Sema` into multiple classes). Table of contents added at the very
beginning of `Sema`. Grouping is reflected in Doxygen commands, so
structure of API reference of `Sema` is also significantly improved
([example from official
documentation](https://www.doxygen.nl/manual/examples/memgrp/html/class_memgrp___test.html),
[comparison of Sema API
reference](https://github.com/llvm/llvm-project/pull/82217#issuecomment-1954567763)).

While grouping is intentional, as well as each group consisting of
`public` declarations followed by `private` ones (without changing
access in-between), exact contents and order of declarations of each
group is partially carried over from old structure, partially accidental
due to time constrains to do the regrouping over the weekend (`Sema` is
just enormously big). Data members and inline function definitions in
`Sema.h` complicate the matter, since it's not obvious which group they
belong to. Further work is expected to refine contents and order of
declarations.

What is also intentional is some kind of layering, where Concepts group
follows template groups, and ObjC, code completion, CUDA, HLSL, OpenACC,
OpenMP, and SYCL are all placed at the end of the file, after C and C++
parts of `Sema`.

I used `clang-query` to verify that access specifiers were preserved
during the process (https://gcc.godbolt.org/z/9johffY9T, thank you
@ilya-biryukov). Only the following 3 member types were converted from
`private` to `public` because of limitations of the new grouping:
`DeclareTargetContextInfo`, `TypoExprState`, `SatisfactionStackEntryTy`.

Member initializer list of `Sema` in `Sema.cpp` is rewritten to reflect
new order of data members in order to avoid `-Wreorder-ctor`.

Since this patch touches almost every line in `Sema.h`, it was
considered appropriate to run clang-format on the whole file, and not
just on changed lines.

When a variadic argument is expected but not provided the compilation
fails later with a difficult to follow compilation error. Add a simple
check to catch one such case.

This is not yet general as it doesn't yet check leaf nodes.

gfx940 does not allow abs/sext/neg on v_cvt_fp8/bf8 & pk variants.

Fixes SWDEV-447468

LLVM does not have the corresponding ClangTidy check enabled, so we
should not be fixing such findings.

This is another follow-up of #83004. `NVVM/Target.cpp` uses the macro
`MLIR_NVPTXCOMPILER_ENABLED`, which is defined in `llvm-config.h` but
did not include that file, yielding a warning when compiled with
`-Wundef`. This PR adds the include.

~~This is another follow-up of #83004, which made the same change for
`MLIR_CUDA_CONVERSIONS_ENABLED`. As the previous PR, this PR commit
exposes mentioned CMake variable through `mlir-config.h` and uses the
macro that is introduced with the same name. This replaces the macro
`MLIR_NVPTXCOMPILER_ENABLED`, which the CMake files previously defined
manually.~~

This is another follow-up of #83004. The PR replaces the macro
`MLIR_GPU_TO_HSACO_PASS_ENABLE` with the more generic macro
`MLIR_ENABLE_ROCM_CONVERSIONS`. Until now, the former has been defined
if and only if the latter evaluated to true in CMake. However, the
former was not defined when the latter evaluated to false, in which case
a warning was raised if compiled with `-Wundef`. Using a single macro
relies on the `#cmakedefine01` mechanism that ensures the macro is
always set to either 0 or 1.

The implementation mostly reuses C++ code paths where possible,
including narrowing check in order to provide diagnostic messages in
case initializer for constexpr variable is not exactly representable in
target type.

The following won't work due to lack of support for other features:
- Diagnosing of underspecified declarations involving constexpr
- Constexpr attached to compound literals

Also due to lack of support for char8_t some of examples with utf-8
strings don't work properly.

Fixes https://github.com/llvm/llvm-project/issues/64742

Instructions in unreachable basic blocks are removed, but terminators
are not. In this case, even instructions that are only referenced by
a terminator, such as a return instruction, cannot be processed
properly.

This patch changes the operand of a return instruction in an
unreachable basic block to poison if it refers to the instruction,
allowing the instruction to be properly processed.

Fixes #65107.

When replacing with a non-constant, it's possible that the result of the
simplification is actually more complicated than the original, and may
result in an infinite combine loop.

Mitigate the issue by requiring that either the replacement or
simplification result is constant, which should ensure that it's
simpler. While this check is crude, it does not appear to cause
optimization regressions in real-world code in practice.

Fixes https://github.com/llvm/llvm-project/issues/83127.

This patch covers the following defect reports:
[CWG438](https://cplusplus.github.io/CWG/issues/438.html) "Possible flaw
in wording for multiple accesses to object between sequence points",
[CWG439](https://cplusplus.github.io/CWG/issues/439.html) "Guarantees on
casting pointer back to cv-qualified version of original type",
[CWG441](https://cplusplus.github.io/CWG/issues/441.html) "Ordering of
static reference initialization",
[CWG462](https://cplusplus.github.io/CWG/issues/462.html) "Lifetime of
temporaries bound to comma expressions",
[CWG492](https://cplusplus.github.io/CWG/issues/492.html) "`typeid`
constness inconsistent with example".

[CWG475](https://cplusplus.github.io/CWG/issues/475.html) "When is
`std::uncaught_exception()` true? (take 2)" requires a libc++abi test.
As for [CWG454](https://cplusplus.github.io/CWG/issues/454.html) "When
is a definition of a static data member required?", I don't feel
confident in my understanding of it, so skipping over it.

These test cases show (op (ext a), (ext b)) patterns where the dest EEW is
more than 2 * source EEW. These could be lowered into widening ops where we
still have extend the operands, but at a smaller EEW.

Close https://github.com/llvm/llvm-project/issues/84002

Per [module.import]p7:

> Additionally, when a module-import-declaration in a module unit of
> some module M imports another module unit U of M, it also imports all
> translation units imported by non-exported module-import-declarations
> in the module unit purview of U.

However, we only tried to implement it during the implicit import of
primary module interface for module implementation unit.

Also we didn't implement the last sentence from [module.import]p7
completely:

> These rules can in turn lead to the importation of yet more
> translation units.

This patch tries to care the both issues.

So that we can benefit from some instcombine optimizations.

This PR contains two commits: the first is for adding tests and the
second is for the optimization.