Reverts
https://github.com/llvm/llvm-project/commit/3bcccb6af685c3132a9ee578b9e11b2503c35a5c
and
https://github.com/llvm/llvm-project/commit/9a282724a29899e84adc91bdeaf639010408a80d
because #91469 causes a miscompilation
https://github.com/llvm/llvm-project/pull/91469#discussion_r1623925158.

Removed foo-registered-target constraints from a bunch of tests, because
mostly the driver doesn't need to have a target availabile. I ran
check-clang-driver using a build with only the XCore target, and these
all passed.

There are ~50 tests that still have foo-registered-target, and it looks
like most of them are either doing codegen when they don't need to, or
don't really belong in the Driver tests. But that's a task for another
day.

Check whether parsing of the argument failed before attempting
to build the expression. 

Fixes #80474.

Noticed while triaging the failures on #93673 - the attributor pass doesn't emit any range metadata in these tests

We add a feature that prevents the GlobalMerge pass from considering
data smaller than a minimum size in bytes for merging.

The MinSize is set in 3 ways:
1. If global-merge-min-data-size is explicitly set, then it uses that
value.
2. If SmallDataLimit is set and non-zero, then SmallDataLimit + 1 is
used.
3. Otherwise, 0 is used, which means all sizes are considered for
merging.

We found that this feature allowed us to see the benefit of the
GlobalMerge pass while eliminating some merging that was not beneficial.
This feature allowed us to enable the GlobalMerge pass on RISC-V in our
downstream by default because it led to improvements on multiple
benchmark suites.

I plan to post a separate patch to propose enabling this by default on
RISC-V. But I do not want that discussion to be part of the discussion
of adding this feature, so I am keeping the patches separate.

To make sure these are preserved when icmp constant expressions
are removed.

This PR fixes legalize info for G_BITREVERSE.

Moving the body of member functions out-of-line makes sense for classes
defined in implementation files too.

Make sure this test is preserved when icmp constant expressions
are removed.

Also mark the test as nounwind. The unwinding information does
not appear to be pertinent to the original intent of the test.

In #94167 I found out that `cwg28xx.cpp` has been running without
`-pedantic-errors` and fixed that. This patch fixes that for the rest of
the test suite. Only one test was affected with a trivial fix (warning
was escalated to an error).

I'm intentionally leaving out test for CWG2390, because it requires
major surgery. It's addressed in #94206.

Similar to the change previously made for binops, make m_Trunc()
only match instructions, not constant expressions. This is more
likely to cause a crash than do something useful.

Fixes crash reported at:
https://github.com/llvm/llvm-project/pull/92885#issuecomment-2145034670

SCEVLoopGuardRewriter only replaces operands with equivalent values, so
we should be able to transfer the flags from the original expression.

PR: https://github.com/llvm/llvm-project/pull/91472

After recent improvements (#80029) and testing on open-source projects,
the checker is ready to move out of the alpha package.

Avoid std::vector copies as setDefaultProperties just iterates across the Records

Fixes #89207

goma is deprecated and not maintained anymore.

https://chromium.googlesource.com/infra/goma/client/

This commit lowers bitwise arith ops to EmitC and also brings in `adaptValueType` and `adaptIntegralTypeSignedness` that other ArithToEmitC functions can benefit from.

After commit 1792852f ([symbolizer] Change reaction on invalid
input) llvm-symbolizer issues an error on malformed command instead of
echoing it to the standard output, as in previous versions. It turns out
this behavior broke a use case when echoing was used to check if
llvm-symbolizer is working (https://github.com/llvm/llvm-project/commit/1792852f86dc75efa1f44d46b1a0daf386d64afa#commitcomment-142161925

).

With this change an empty line as input is not considered as an error
anymore and does not produce any output on stderr. llvm-symbolizer still
respond on empty line with line not found, this is consistent with GNU
addr2line.

---------

Co-authored-by: James Henderson <46713263+jh7370@users.noreply.github.com>

This reverts commit ccb73e88.

It looks like there are some bots complaining about the patch.
See the post commit comment in
https://github.com/llvm/llvm-project/pull/92083 to track it.

Currently we only match GEPs with a scalar base pointer, but a common
pattern that's emitted from the loop vectorizer is a strided vector base
plus some sort of scalar offset:

    %base = getelementptr i64, ptr %p, <vscale x 1 x i64> %step
    %gep = getelementptr i64, <vscale x 1 x ptr> %base, i64 %offset

This is common for accesses into a struct e.g. f[i].b below:

    struct F { int a; char b; };

    void foo(struct F *f) {
      for (int i = 0; i < 1024; i += 2) {
        f[i].a++;
        f[i].b++;
      }
    }

This patch handles this case in RISCVGatherScatterLowering by recursing
on the base pointer if it's a vector.

With this we can convert roughly 80% of the indexed loads and stores
emitted to strided loads and stores on SPEC CPU 2017, -O3
-march=rva22u64_v

`std::aligned_storage` is deprecated with C++23, see
[here](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1413r3.pdf).

This replaces the usages of `std::aligned_storage` within llvm (only one
in ADT and one in Support) with an aligned `std::byte` array.
I will provide patches for other subcomponents as well.

This patch adds tests for some CWG issues that were discussed at
2024-05-31 telecon. While all of them are tentatively ready at the
moment, I'm expecting them to be moved to DRs without changes. CWG
issues that are expected to have follow-ups are not included in this PR.

I also realized that `cwg28xx.cpp` has been testing without
`-pedantic-errors`. I fixed that. Fortunately, no existing tests had
anything hidden by the lack of this flag.

The following CWG issues are covered:
[CWG2877](https://cplusplus.github.io/CWG/issues/2877.html) "Type-only
lookup for _using-enum-declarator_"
[CWG2882](https://cplusplus.github.io/CWG/issues/2882.html) "Unclear
treatment of conversion to `void`"
[CWG2883](https://cplusplus.github.io/CWG/issues/2883.html) "Definition
of "odr-usable" ignores lambda scopes"
[CWG2885](https://cplusplus.github.io/CWG/issues/2885.html)
"Non-eligible trivial default constructors"
[CWG2886](https://cplusplus.github.io/CWG/issues/2886.html) "Temporaries
and trivial potentially-throwing special member functions"

The structurizer required regions to be SESE: single entry, single exit.
This new pass transforms multiple-exit regions into single-exit regions.

```
      +---+
      | A |
      +---+
      /   \
   +---+ +---+
   | B | | C |  A, B & C belongs to the same convergence region.
   +---+ +---+
     |     |
   +---+ +---+
   | D | | E |  C & D belongs to the parent convergence region.
   +---+ +---+  This means B & C are the exit blocks of the region.
      \   /     And D & E the targets of those exits.
       \ /
        |
      +---+
      | F |
      +---+
```

This pass would assign one value per exit target:
B = 0
C = 1

Then, create one variable per exit block (B, C), and assign it to the
correct value: in B, the variable will have the value 0, and in C, the
value 1.

Then, we'd create a new block H, with a PHI node to gather those 2
variables, and a switch, to route to the correct target.

Finally, the branches in B and C are updated to exit to this new block.

```
      +---+
      | A |
      +---+
      /   \
   +---+ +---+
   | B | | C |
   +---+ +---+
      \   /
      +---+
      | H |
      +---+
      /   \
   +---+ +---+
   | D | | E |
   +---+ +---+
      \   /
       \ /
        |
      +---+
      | F |
      +---+
```

Note: the variable is set depending on the condition used to branch. If
B's terminator was conditional, the variable would be set using a
SELECT.
All internal edges of a region are left intact, only exiting edges are
updated.

---------

Signed-off-by: Nathan Gauër <brioche@google.com>

Fixes a bug uncovered by
[pr43337.f90](https://github.com/llvm/llvm-test-suite/blob/main/Fortran/gfortran/regression/gomp/pr43337.f90)
in the test suite.

In particular, this emits `argNo` debug info only if the parent op of a
block is a `func.func` op. This avoids DI conflicts when a function
contains a nested OpenMP region that itself has block arguments with DI
attached to them; for example, `omp.parallel` with delayed privatization
enabled.

The Zabha extension was ratified in April 2024.

Co-authored-by: Alexandre Ghiti <alexghiti@rivosinc.com>

On Windows the function does not have a symbol associated with it:
Function: id = {0x000001c9}, name = "_Dfunction", range =
[0x0000000140001000-0x0000000140001004)
      LineEntry: <...>

Whereas it does on Linux:
Function: id = {0x00000023}, name = "_Dfunction", range =
[0x0000000000000734-0x0000000000000738)
      LineEntry: <...>
Symbol: id = {0x00000058}, range =
[0x0000000000000734-0x0000000000000738), name="_Dfunction"

This means that frame.symbol is not valid on Windows.

However, frame.function is valid and it also has a "mangled" attribute.

So I've updated the test to check the symbol if we've got it, and the
function always.

In both cases we check that mangled is empty (meaning it has not been
treated as mangled) and that the display name matches the original
symbol name.

The pass constructor can be generated automatically.

This pass doesn't need to be adapted to support other top level
operations because it is specifically supposed to filter functions. We
don't need to filter non-function top level operations because without
use inside of functions they shouldn't lead to any codegen.

While the fix is reviewed.

For some data formatters, even getting the number of children can be an
expensive operations (e.g., needing to walk a linked list to determine
the number of elements). This is then wasted work when we know we will
be printing only small number of them.

This patch replaces the calls to GetNumChildren (at least those on the
"frame var" path) with the calls to the capped version, passing the
value of `max-children-count` setting (plus one)

This PR fixes invalid OpGroupWaitEvents emission to ensure that SPIR-V
Backend inserts a bitcast before OpGroupWaitEvents if the last argument
is a pointer that doesn't point to OpTypeEvent.

Instcombine will convert fdiv by a power-2 to fmul, this converts the
PerformVDIVCombine that converts fdiv+fcvt to fixed-point fcvt to fmul+fcvt.
The fdiv tests will look worse, but won't appear in practice (and should be
improved again by #93882).

For streaming-compatible functions with only +sme, we can't use
a NEON ORR (aliased as 'mov') for copies of Q-registers, so
we need to use a spill/fill instead.

This also fixes the fill, which should use the post-incrementing
addressing mode.

Following of https://github.com/llvm/llvm-project/pull/86912

#### Motivation Example

The motivation of the patch series is that, for a module interface unit
`X`, when the dependent modules of `X` changes, if the changes is not
relevant with `X`, we hope the BMI of `X` won't change. For the specific
patch, we hope if the changes was about irrelevant declaration changes,
we hope the BMI of `X` won't change. **However**, I found the patch
itself is not very useful in practice, since the adding or removing
declarations, will change the state of identifiers and types in most
cases.

That said, for the most simple example,

```
// partA.cppm
export module m:partA;

// partA.v1.cppm
export module m:partA;
export void a() {}

// partB.cppm
export module m:partB;
export void b() {}

// m.cppm
export module m;
export import :partA;
export import :partB;

// onlyUseB;
export module onlyUseB;
import m;
export inline void onluUseB() {
    b();
}
```

the BMI of `onlyUseB` will change after we change the implementation of
`partA.cppm` to `partA.v1.cppm`. Since `partA.v1.cppm` introduces new
identifiers and types (the function prototype).

So in this patch, we have to write the tests as:

```
// partA.cppm
export module m:partA;
export int getA() { ... }
export int getA2(int) { ... }

// partA.v1.cppm
export module m:partA;
export int getA() { ... }
export int getA(int) { ... }
export int getA2(int) { ... }

// partB.cppm
export module m:partB;
export void b() {}

// m.cppm
export module m;
export import :partA;
export import :partB;

// onlyUseB;
export module onlyUseB;
import m;
export inline void onluUseB() {
    b();
}
```

so that the new introduced declaration `int getA(int)` doesn't introduce
new identifiers and types, then the BMI of `onlyUseB` can keep
unchanged.

While it looks not so great, the patch should be the base of the patch
to erase the transitive change for identifiers and types since I don't
know how can we introduce new types and identifiers without introducing
new declarations. Given how tightly the relationship between
declarations, types and identifiers, I think we can only reach the ideal
state after we made the series for all of the three entties.

#### Design details

The design of the patch is similar to
https://github.com/llvm/llvm-project/pull/86912, which extends the
32-bit DeclID to 64-bit and use the higher bits to store the module file
index and the lower bits to store the Local Decl ID.

A slight difference is that we only use 48 bits to store the new DeclID
since we try to use the higher 16 bits to store the module ID in the
prefix of Decl class. Previously, we use 32 bits to store the module ID
and 32 bits to store the DeclID. I don't want to allocate additional
space so I tried to make the additional space the same as 64 bits. An
potential interesting thing here is about the relationship between the
module ID and the module file index. I feel we can get the module file
index by the module ID. But I didn't prove it or implement it. Since I
want to make the patch itself as small as possible. We can make it in
the future if we want.

Another change in the patch is the new concept Decl Index, which means
the index of the very big array `DeclsLoaded` in ASTReader. Previously,
the index of a loaded declaration is simply the Decl ID minus
PREDEFINED_DECL_NUMs. So there are some places they got used
ambiguously. But this patch tried to split these two concepts.

#### Overhead

As https://github.com/llvm/llvm-project/pull/86912 did, the change will
increase the on-disk PCM file sizes. As the declaration ID may be the
most IDs in the PCM file, this can have the biggest impact on the size.
In my experiments, this change will bring 6.6% increase of the on-disk
PCM size. No compile-time performance regression observed. Given the
benefits in the motivation example, I think the cost is worthwhile.

[P2231R1](https://wg21.link/P2231R1) "Missing `constexpr` in
`std::optional` and `std::variant`" was accepted as a C++20 Defect
Report, not a C++17 Defect Report. Accordingly, `test_empty_emplace()`
and `check_reset()` should be marked as `TEST_CONSTEXPR_CXX20`. Note
that their `static_assert`s are properly guarded:


https://github.com/llvm/llvm-project/blob/4ce65423be0ba1d90c11b6a79981d6314e1cf36d/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp#L270-L272


https://github.com/llvm/llvm-project/blob/4ce65423be0ba1d90c11b6a79981d6314e1cf36d/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp#L53-L55

Found while running libc++'s tests with MSVC's STL, as we activate our
`constexpr` here for C++20 and above.