## Introduction

This proposal describes the new op to be added to the `std` (and later moved `memref`)
dialect called `alloca_scope`.

## Motivation

Alloca operations are easy to misuse, especially if one relies on it while doing
rewriting/conversion passes. For example let's consider a simple example of two
independent dialects, one defines an op that wants to allocate on-stack and
another defines a construct that corresponds to some form of looping:

```
dialect1.looping_op {
  %x = dialect2.stack_allocating_op
}
```

Since the dialects might not know about each other they are going to define a
lowering to std/scf/etc independently:

```
scf.for … {
   %x_temp = std.alloca …
   … // do some domain-specific work using %x_temp buffer
   … // and store the result into %result
   %x = %result
}
```

Later on the scf and `std.alloca` is going to be lowered to llvm using a
combination of `llvm.alloca` and unstructured control flow.

At this point the use of `%x_temp` is bound to either be either optimized by
llvm (for example using mem2reg) or in the worst case: perform an independent
stack allocation on each iteration of the loop. While the llvm optimizations are
likely to succeed they are not guaranteed to do so, and they provide
opportunities for surprising issues with unexpected use of stack size.

## Proposal

We propose a new operation that defines a finer-grain allocation scope for the
alloca-allocated memory called `alloca_scope`:

```
alloca_scope {
   %x_temp = alloca …
   ...
}
```

Here the lifetime of `%x_temp` is going to be bound to the narrow annotated
region within `alloca_scope`. Moreover, one can also return values out of the
alloca_scope with an accompanying `alloca_scope.return` op (that behaves
similarly to `scf.yield`):

```
%result = alloca_scope {
   %x_temp = alloca …
   …
   alloca_scope.return %myvalue
}
```

Under the hood the `alloca_scope` is going to lowered to a combination of
`llvm.intr.stacksave` and `llvm.intr.strackrestore` that are going to be invoked
automatically as control-flow enters and leaves the body of the `alloca_scope`.

The key value of the new op is to allow deterministic guaranteed stack use
through an explicit annotation in the code which is finer-grain than the
function-level scope of `AutomaticAllocationScope` interface. `alloca_scope`
can be inserted at arbitrary locations and doesn’t require non-trivial
transformations such as outlining.

## Which dialect

Before memref dialect is split, `alloca_scope` can temporarily reside in `std`
dialect, and later on be moved to `memref` together with the rest of
memory-related operations.

## Implementation

An implementation of the op is available [here](https://reviews.llvm.org/D97768).

Original commits:

* Add initial scaffolding for alloca_scope op
* Add alloca_scope.return op
* Add no region arguments and variadic results
* Add op descriptions
* Add failing test case
* Add another failing test
* Initial implementation of lowering for std.alloca_scope
* Fix backticks
* Fix getSuccessorRegions implementation

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D97768

Update LLDB for thew new Objective-C hash table layout in the dyld
shared cache found in macOS Monterey.

rdar://72863911

It was found by chance revealing discrepancy between comment (few lines above),
the condition and how re-ordering of instruction is done inside the if statement
it guards. The condition was always evaluated to true.

Differential Revision: https://reviews.llvm.org/D104064

There's no fundamental reason to separate those from the other iterator
concepts.

Differential Revision: https://reviews.llvm.org/D104048

In function searchALUInst, sub register usage of LEA dest should also block LEA/SUB optimization, otherwise the sub register usage gets an undefined value.

This patch fixes https://bugs.llvm.org/show_bug.cgi?id=50615.

Differential Revision: https://reviews.llvm.org/D103922

The synchronization library was marked as disabled on Apple platforms
up to now because we were not 100% sure that it was going to be ABI
stable. However, it's been some time since we shipped it in upstream
libc++ now and there's been no changes so far. This patch enables the
synchronization library on Apple platforms, and hence commits the ABI
stability as far as that vendor is concerned.

Differential Revision: https://reviews.llvm.org/D96790

Basically the title.

Differential Revision: https://reviews.llvm.org/D102006

Without the fix the testcase crashes because we remove the same instruction
twice.

Differential Revision: https://reviews.llvm.org/D104127

Allow the usage of minor version 0, for hip versions
such as 4.0. Change the default values when performing
version checks.

Reviewed By: yaxunl

Differential Revision: https://reviews.llvm.org/D104062

If an inferior exits prior to the processing of a disconnect request,
then the threads executing EventThreadFunction and request_discontinue
respectively may call SendTerminatedEvent simultaneously, in turn,
testing and/or setting g_vsc.sent_terminated_event without any
synchronization. In case the thread executing EventThreadFunction sets
it before the thread executing request_discontinue has had a chance to
test it, the latter would move ahead to issue a response to the
disconnect request. Said response may be dispatched ahead of the
terminated event compelling the client to terminate the debug session
without consuming any console output that might've been generated by
the execution of terminateCommands.

Reviewed By: clayborg, wallace

Differential Revision: https://reviews.llvm.org/D103609

This adds implementation information for N2607,
clarifies that C17 only resolved defect reports,
and adds -std= information for the different versions.

Register allocation may spill virtual registers to the stack, which can
increase alignment requirements of the stack frame. If the the function
did not require stack realignment before register allocation, the
registers required to do so may not be reserved/available. This results
in a stack frame that requires realignment but can not be realigned.

Instead, only increase the alignment of the stack if we are still able
to realign.

The register SpillAlignment will be ignored if we can't realign, and the
backend will be responsible for emitting the correct unaligned loads and
stores. This seems to be the assumed behaviour already, e.g.
ARMBaseInstrInfo::storeRegToStackSlot and X86InstrInfo::storeRegToStackSlot
are both `canRealignStack` aware.

Differential Revision: https://reviews.llvm.org/D103602

After we added support for non-ordered insertelements, we can allow
their reordering.

Differential Revision: https://reviews.llvm.org/D104057

This reverts commit e42a347b.

Check applied to unbounded (incomplete) arrays and pointers to spot
cases where the computed address is beyond the largest possible
addressable extent of the array, based on the address space in which the
array is delcared, or which the pointer refers to.

Check helps to avoid cases of nonsense pointer math and array indexing
which could lead to linker failures or runtime exceptions.  Of
particular interest when building for embedded systems with small
address spaces.

This is version 2 of this patch -- version 1 had some testing issues
due to a sign error in existing code.  That error is corrected and
lit test for this chagne is extended to verify the fix.

Originally reviewed/accepted by: aaron.ballman
Original revision: https://reviews.llvm.org/D86796

Reviewed By: aaron.ballman, ebevhan

Differential Revision: https://reviews.llvm.org/D88174

Adds the basic instrumentation needed for stack tagging.

Currently does not support stack short granules or TLS stack histories,
since a different code path is followed for the callback instrumentation
we use.

We may simply wait to support these two features until we switch to
a custom calling convention.

Patch By: xiangzhangllvm, morehouse

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D102901

Not sure sectionType() carries its weight, but while we have it
we should use it consistently.

No behavior change.

Differential Revision: https://reviews.llvm.org/D104027

No need to use UndefValue in CreateShuffle call.

Differential Revision: https://reviews.llvm.org/D104113

This is the first step to convert vector ops to MMA operations in order to
target GPUs tensor core ops. This currently only support simple cases,
transpose and element-wise operation will be added later.

Differential Revision: https://reviews.llvm.org/D102962

This passes with GCC>8.5 and ToT LLDB.

This works for GCC>8.5 and ToT LLDB.

As a follow up of rGc4a0969b, and as part of D104102, move it to
the IPO transformations directory.

generating an erroneous warning.

See here: https://godbolt.org/z/ajKPc36M7

'override' [-Werror,-Wsuggest-override]" occuring during windows
debug self-build.

Adapt pad to static bounding box to support structured ops taking scalar operands.

Differential Revision: https://reviews.llvm.org/D103891

The problematic code pattern in the test is based on:
https://llvm.org/PR50638

If the IfCond is itself the phi that we are trying to remove,
then the loop around line 2835 can end up with something like:
%cmp = select i1 %cmp, i1 false, i1 true

That can then lead to a use-after-free and assert (although
I'm still not seeing that locally in my release + asserts build).

I think this can only happen with unreachable code.

Differential Revision: https://reviews.llvm.org/D104063

Adapt drop unit dims for structured ops taking scalar operands.

Differential Revision: https://reviews.llvm.org/D103890

This reverts commit 00764c36 and the
follow up d2223c7a.

The original patch broke that one could use static member variables while
inside a static member functions without having a running target. It seems that
LLDB currently requires that static variables are only found via the global
variable lookup so that they can get materialized and mapped to the argument
struct of the expression.

After 00764c36 static variables of the current
class could be found via Clang's lookup which LLDB isn't observing. This
resulting in expressions actually containing these variables as normal
globals that can't be rewritten to a member of the argument struct.

More specifically, in the test TestCPPThis, the expression
`expr --j false -- s_a` is now only passing if we have a runnable target.

I'll revert the patch as the possible fixes aren't trivial and it degrades
the debugging experience more than the issue that the revert patch addressed.

The underlying bug can be reproduced before/after this patch by stopping
in `TestCPPThis` main function and running: `e -j false -- my_a; A<int>::s_a`.
The `my_a` will pull in the `A<int>` class and the second expression will
be resolved by Clang on its own (which causes LLDB to not materialize the
static variable).

Note: A workaround is to just do `::s_a` which will force LLDB to take the global
variable lookup.

Cleanup the refactoring started by https://reviews.llvm.org/D103394.

Differential Revision: https://reviews.llvm.org/D104025

This is part of an effort to reduce the differences between the custom C++ bindings used right now by polly in `lib/External/isl/include/isl/isl-noxceptions.h` and the official isl C++ interface.

Changes made:
 - Removing explicit operator bool() from all the classes in the isl C++ bindings.
 - Replace each call to operator bool() to method `is_null()`.
 - isl-noexceptions.h has been generated by this https://github.com/patacca/isl/commit/27396daac5a5ee8228d25511a12f4a814c92ba8f

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D103976

APInt::toString() was removed rG61cdaf66