Introduce RecordVisitor. This is used for different clients that want to
extract information out of RecordSlice types.
The first and immediate usecase is for serializing symbol information
into TBD files.

This mask is an implementation detail of `FPBits` and shouldn't really
leak outside of it.

Lower procedure pointer components, except in the context of structure
constructor (left TODO).

Procedure pointer components lowering share most of the lowering logic
of procedure poionters with the following particularities:
- They are components, so an hlfir.designate must be generated to
retrieve the procedure pointer address from its derived type base.
- They may have a PASS argument. While there is no dispatching as with
type bound procedure, special care must be taken to retrieve the derived
type component base in this case since semantics placed it in the
argument list and not in the evaluate::ProcedureDesignator.

These components also bring a new level of recursive MLIR types since a
fir.type may now contain a component with an MLIR function type where
one of the argument is the fir.type itself. This required moving the
"derived type in construction" stackto the converter so that the object
and function type lowering utilities share the same state (currently the
function type utilty would end-up creating a new stack when lowering its
arguments, leading to infinite loops). The BoxedProcedurePass also
needed an update to deal with this recursive aspect.

The SiFive7 scheduler model has been using AcquireAtCycles and
ReleaseAtCycles for some time. Without EnableIntervals, the scheduler
was not making decisions based on this information. This patch sets
EnableIntervals to true, and the test case demonstrates that the VADD
instructions can be issued one cycle earlier since the VCQ is not
reserved. This leads to better saturation of the SiFive7VA.

[compiler-rt]Add lld into dependency for apple builds now that lld Mach-O backend is available (#75884)

Tested by `ninja check-profile` and all tests pass on a mac laptop.

Pass the original MMO instead of different individual values.

getAlign() was used before where actually getOriginalAlign() would have been
better, and this patch has the same effect.

Avoid the pre-truncate of BUILD_VECTOR sources when there is more than
one use. This can avoid using unnecessary movs later down the
instruction selection pipeline.

Drop custom selector code for ptrauth_(sign|strip|blend) intrinsics from
AArch64InstructionSelector::selectIntrinsic function.

The code for strip and blend intrinsics was needed because of a bug in
TableGen fixed in 78623b07. The
ptrauth_sign intrinsic was presumably fixed long ago.

Abort fusion if memref load may alias write, but not the exact alias. 
Add alias check hook to `naivelyFuseParallelOps`, so user can customize
alias checking.
Use builtin alias analysis in `ParallelLoopFusion` pass.

A miscompilation issue has been addressed with improved checking.

Fixes: https://github.com/llvm/llvm-project/issues/75822.

The changes to this test uncovered a pre-existing issue that I've
documented in the linked issue.

This will already be checked inside markConstant().

We shouldn't need to link against libc++ or libc++abi when building
libunwind, since that would otherwise be a circular dependency.

Adds the following SME2 builtins:
 - svread_hor/ver,
 - svwrite_hor/ver,
 - svread_za64,
 - svwrite_za64

See https://github.com/ARM-software/acle/pull/217

This fixes https://github.com/llvm/llvm-project/issues/64347.

The CTAD for an aggregate class is missing to handle the explicit type
conversion case, e.g. `TemplateFooClass(1, 2);`. Per C++ expr.type.conv
p1, the deduced type is the return type of the deduction guide selected
by the CTAD for the reminder.

In the deduction implementation
`DeduceTemplateSpecializationFromInitializer`, the parenthesized
express-list case relies on the `ParenListExpr` parameter (default is
nullptr), the AST `ParenListExpr` node is not built for all variant
initializer cases (`BuildCXXTypeConstructorExpr`, `BuildCXXNew` etc),
thus the deduction doesn't perform for these cases. This patch fixes it
by removing the `ParenListExpr` and using the `Inits` instead (which
also simplifies the interface and implementation).

Only used in ConstantFoldCompareInstOperands(), which does not
actually use TLI.

Extend the `amendOperation` mechanism for translating dialect attributes
attached to operations from another dialect when translating MLIR to
LLVM IR. Previously, this mechanism would have no knowledge of the LLVM
IR instructions created for the given operation, making it impossible
for it to perform local modifications such as attaching operation-level
metadata. Collect instructions inserted by the LLVM IR builder and pass
them to `amendOperation`.

Before this patch the compiler could generate unnecessary calls to the
selected implementation.
https://clang.llvm.org/docs/AttributeReference.html#flatten

If the base was poison, retain the poison value.

`createFunctionType` returns a FunctionType  that may contain a mask,
which is currently placed as the last parameter to the Function.
The placement happens according to `VFParameters` of `VFInfo`, and it
should be able to handle VFABI specification changes.

Regarding the return type, it uses the scalar type of the input instruction,
as the specification does not encode in the mangled name such information.
If that ever happens, that information should be available from `VFInfo`.

This one doesn't seem to make a practical difference because we'd
canonicalize undef -> poison in the relevant cases anywy.

We can only set PoisonElts if the element is poison, not if it is
undef.

When constructing vectors from elements, use poison instead of
undef as the base value. These literals always initialize all
elements (padding the remainder with zero), so that the choice
of base value does not affect semantics.

[llvm-cov] format cells in report with 0/0 branches/functions/lines differenly (gray instead red) and make the table a bit nicer (#75780)

The reference could be const, but this is even better.

The followed byte of `OPC_EmitRegister` is a MVT type, which is
usually i32 or i64.

We add `OPC_EmitRegisterI32` and `OPC_EmitRegisterI64` so that we
can reduce one byte.

Overall this reduces the llc binary size with all in-tree targets by
about 10K.

By commit 12ed2c90.

Fixes #75736

And const qualify some local variables

Lowering was instantiating component symbols (but the last) in initial
target designator as if they were whole objects, leading to collisions
and bugs.

Fixes https://github.com/llvm/llvm-project/issues/75728