[IRBuilder] Generate nuw GEPs for struct member accesses (#99538)

Generate nuw GEPs for struct member accesses, as inbounds + non-negative
implies nuw.

Regression tests are updated using update

[IRBuilder] Generate nuw GEPs for struct member accesses (#99538)

Generate nuw GEPs for struct member accesses, as inbounds + non-negative
implies nuw.

Regression tests are updated using update scripts where possible, and by
find + replace where not.

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[CodeGen] Simplify codegen for array initialization (#93956)

This makes codegen for array initialization simpler in two ways:
1. Drop the zero-index GEP at the start, which is no longer needed with

[CodeGen] Simplify codegen for array initialization (#93956)

This makes codegen for array initialization simpler in two ways:
1. Drop the zero-index GEP at the start, which is no longer needed with
opaque pointers.
2. Emit GEPs directly to the correct element, instead of having a long
chain of +1 GEPs. This is more canonical, and also avoids regressions in
unoptimized builds from #93823.

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[OpenMP] Increment kernel args version, used by runtime for detecting dyn_ptr. (#85363)

A kernel implicit parameter (dyn_ptr) was introduced some time back.
This patch increments the kernel args ve

[OpenMP] Increment kernel args version, used by runtime for detecting dyn_ptr. (#85363)

A kernel implicit parameter (dyn_ptr) was introduced some time back.
This patch increments the kernel args version for a compiler supporting
dyn_ptr. The version will be used by the runtime to determine whether
the implicit parameter is generated by the compiler. The versioning is
required to support use cases where code generated by an older compiler
is linked with a newer runtime.

If approved, this patch should be backported to release 18.

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[OpenMP] Remove `register_requires` global constructor (#80460)

Summary:
Currently, OpenMP handles the `omp requires` clause by emitting a global
constructor into the runtime for every translation u

[OpenMP] Remove `register_requires` global constructor (#80460)

Summary:
Currently, OpenMP handles the `omp requires` clause by emitting a global
constructor into the runtime for every translation unit that requires
it. However, this is not a great solution because it prevents us from
having a defined order in which the runtime is accessed and used.

This patch changes the approach to no longer use global constructors,
but to instead group the flag with the other offloading entires that we
already handle. This has the effect of still registering each flag per
requires TU, but now we have a single constructor that handles
everything.

This function removes support for the old `__tgt_register_requires` and
replaces it with a warning message. We just had a recent release, and
the OpenMP policy for the past four releases since we switched to LLVM
is that we do not provide strict backwards compatibility between major
LLVM releases now that the library is versioned. This means that a user
will need to recompile if they have an old binary that relied on
`register_requires` having the old behavior. It is important that we
actively deprecate this, as otherwise it would not solve the problem of
having no defined init and shutdown order for `libomptarget`. The
problem of `libomptarget` not having a define init and shutdown order
cascades into a lot of other issues so I have a strong incentive to be
rid of it.

It is worth noting that the current `__tgt_offload_entry` only has space
for a 32-bit integer here. I am planning to overhaul these at some point
as well.

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Diagnose use of VLAs in C++ by default

Reapplication of 7339c0f782d5c70e0928f8991b0c05338a90c84c with a fix
for a crash involving arrays without a size expression.

Clang supports VLAs in C++ as an

Diagnose use of VLAs in C++ by default

Reapplication of 7339c0f782d5c70e0928f8991b0c05338a90c84c with a fix
for a crash involving arrays without a size expression.

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565

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Revert "Diagnose use of VLAs in C++ by default"

This reverts commit 7339c0f782d5c70e0928f8991b0c05338a90c84c.

Breaks bots:
https://lab.llvm.org/buildbot/#/builders/139/builds/51875
https://lab.llvm

Revert "Diagnose use of VLAs in C++ by default"

This reverts commit 7339c0f782d5c70e0928f8991b0c05338a90c84c.

Breaks bots:
https://lab.llvm.org/buildbot/#/builders/139/builds/51875
https://lab.llvm.org/buildbot/#/builders/164/builds/45262

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Diagnose use of VLAs in C++ by default

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they'r

Diagnose use of VLAs in C++ by default

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565

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[OpenMP] Properly set static thread limit (w/o analysis)

We used to have two separate implementations to derive the number of
threads used in a target region. This lead us to sometimes miss out on
u

[OpenMP] Properly set static thread limit (w/o analysis)

We used to have two separate implementations to derive the number of
threads used in a target region. This lead us to sometimes miss out on
user provided thread bounds (num_threads, or thread_limit) when we
looked for "constant default values". If we might miss out on the
presence of those bounds, we cannot set the thread_limit statically
since the runtime will try to honor user input rather than cap it at the
"preferred default". This patch replaces the secondary implementation
with the primary in a mode that will not emit code but just look for the
presence, and potentially upper bounds, of thread limiting clauses.

The runtime test would not pass without this rewrite as we missed some
clauses, set the static limit on the device to the preferred value, but
then violated that value at runtime.

Fixes: https://github.com/llvm/llvm-project/issues/64845

Differential Revision: https://reviews.llvm.org/D158381

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Intrinsics: Add type overload to stacksave and stackstore

This allows use with non-0 address space stacks. llvm_ptr_ty should
never be used. This could use some more percolation up through mlir,
but

Intrinsics: Add type overload to stacksave and stackstore

This allows use with non-0 address space stacks. llvm_ptr_ty should
never be used. This could use some more percolation up through mlir,
but this is enough to fix existing tests.

https://reviews.llvm.org/D156666

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[clang][CodeGenCXX] Improve handling of itanium ABI member function alignment requirements

The itanium ABI for certain platforms requires a minimum alignments for
member function pointers to reserve

[clang][CodeGenCXX] Improve handling of itanium ABI member function alignment requirements

The itanium ABI for certain platforms requires a minimum alignments for
member function pointers to reserve certain bits for distinguishing
virtual and non-virtual functions.

Our implementation of this however depends on the alignment of the
function involved, which may however not reflect the true alignment of
function pointers on certain targets for which the alignment is
independent of the function (e.g. AIX). Worse, the 2-byte alignment
we use may be less than the ABI minimum for the target, and in the case
we are using explicit sections will result in invalid codegen.

This patch attempts to correct this situation by considering the target
alignment of function pointers as part of making the decision about
whether we need to adjust the function alignment to conform to the ABI.
Targets which do not provide the function ptr alignment information
will return a value of 1 when queried and will conservatively retain
the old alignment.

Differential Revision: https://reviews.llvm.org/D147184

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[OpenMP] Prefix outlined and reduction func names with original func's name

This patch prefixes omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

D

[OpenMP] Prefix outlined and reduction func names with original func's name

This patch prefixes omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D140722

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Revert "[OpenMP] Prefix outlined and reduction func names with original func's name"

This reverts commit 029bfc311d4d7d3cd90be81bb08c046848796d02.

[OpenMP] Prefix outlined and reduction func names with original func's name

This patch attempts to prefix omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jd

[OpenMP] Prefix outlined and reduction func names with original func's name

This patch attempts to prefix omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D140722

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Fix accessing of aligned arrays in offloaded target regions

[Clang][OpenMP] Insert alloca for kernel args at function entry block instead of the launch point.

If an inlined kernel is called in a loop, the launch point alloca would
lead to increasing stack us

[Clang][OpenMP] Insert alloca for kernel args at function entry block instead of the launch point.

If an inlined kernel is called in a loop, the launch point alloca would
lead to increasing stack usage every time the kernel is invoked. This
could make the application run out of stack space and crash. This problem
is fixed by using the alloca insertion point while creating the alloca instruction.

Fixes https://github.com/llvm/llvm-project/issues/60602

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D145820

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Reland "[codegen] Store address of indirect arguments on the stack"

The commit was reverted due to a regression in debug information of an
optimized code test in lldb. This has since been addressed

Reland "[codegen] Store address of indirect arguments on the stack"

The commit was reverted due to a regression in debug information of an
optimized code test in lldb. This has since been addressed by:

1. rGf753e5be8239: [LiveDebugValues] Allow EntryValue with OP_deref
expressions
2. rG055f2f04e658: [mem2reg][debuginfo] Handle op_deref when converting
dbg.declare

Differential Revision: https://reviews.llvm.org/D141381

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[OpenMP] Modernize the kernel launching interface and APIs

We already created a versioned `__tgt_kernel_arguments` struct but it
was only briefly used and its content was passed in isolation anyway.

[OpenMP] Modernize the kernel launching interface and APIs

We already created a versioned `__tgt_kernel_arguments` struct but it
was only briefly used and its content was passed in isolation anyway.
This makes it hard to add more information in the future. With this
patch we fully embrace the struct as means to pass information from the
compiler to the plugin as part of a kernel launch.

The patch also extends and renames the struct, bumping the version
number to 2. Version 1 entries are auto-upgraded. This is in preparation
for "bare" kernel launches, per kernel dynamic shared memory, CUDA/HIP
lowering, etc.

The `__tgt_target_kernel_nowait` interface was deprecated as it was
unused. Once we actually implement support for something like that, we
can add an appropriate API.

Note: Only plugins with the `launch_kernel` interface are now supported.
That means that a new clang won't be able to use an old runtime.
An old clang can still use the new runtime since the libomptarget
interface did not change.

Differential Revision: https://reviews.llvm.org/D141232

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Revert "[codegen] Store address of indirect arguments on the stack"

This reverts commit 7e4447a17db4a070f01c8f8a87505a4b2a1b0e3a.

[codegen] Store address of indirect arguments on the stack

With codegen prior to this patch, truly indirect arguments -- i.e.
those that are not `byval` -- can have their debug information lost even

[codegen] Store address of indirect arguments on the stack

With codegen prior to this patch, truly indirect arguments -- i.e.
those that are not `byval` -- can have their debug information lost even
at O0. Because indirect arguments are passed by pointer, and this
pointer is likely placed in a register as per the function call ABI,
debug information is lost as soon as the register gets clobbered.

This patch solves the issue by storing the address of the parameter on
the stack, using a similar strategy employed when C++ references are
passed. In other words, this patch changes codegen from:

```
define @foo(ptr %arg) {
call void @llvm.dbg.declare(%arg, [...], metadata !DIExpression())
```

To:

```
define @foo(ptr %arg) {
%ptr_storage = alloca ptr
store ptr %arg, ptr %ptr_storage
call void @llvm.dbg.declare(%ptr_storage, [...], metadata !DIExpression(DW_OP_deref))
```

Some common cases where this may happen with C or C++ function calls:
1. "Big enough" trivial structures passed by value under the ARM ABI.
2. Structures that are non-trivial for the purposes of call (as per
the Itanium ABI) when passed by value.

A few tests were matching the wrong alloca (matching against the new
alloca, instead of the old one), so they were updated to either match
both allocas or include a `,` right after the alloca type, to prevent
matching against a pointer type.

Differential Revision: https://reviews.llvm.org/D141381

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OpenMP: Use inbounds in EmitOMPAggregateAssign

This looked like a plausibly correct out of tree patch.
The changed testcases with the pragmas stripped out only use
inbounds GEPs so I assume this is

OpenMP: Use inbounds in EmitOMPAggregateAssign

This looked like a plausibly correct out of tree patch.
The changed testcases with the pragmas stripped out only use
inbounds GEPs so I assume this is correct.

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[OpenMP] Convert more tests to opaque pointers (NFC)

These were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34
followed by a re-run of update_cc_test_ch

[OpenMP] Convert more tests to opaque pointers (NFC)

These were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34
followed by a re-run of update_cc_test_checks.py.

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Revert "[OpenMP] Codegen aggregate for outlined function captures"

This reverts commit 7539e9cf811e590d9f12ae39673ca789e26386b4.

[OpenMP] Codegen aggregate for outlined function captures

Parallel regions are outlined as functions with capture variables explicitly generated as distinct parameters in the function's argument lis

[OpenMP] Codegen aggregate for outlined function captures

Parallel regions are outlined as functions with capture variables explicitly generated as distinct parameters in the function's argument list. That complicates the fork_call interface in the OpenMP runtime: (1) the fork_call is variadic since there is a variable number of arguments to forward to the outlined function, (2) wrapping/unwrapping arguments happens in the OpenMP runtime, which is sub-optimal, has been a source of ABI bugs, and has a hardcoded limit (16) in the number of arguments, (3) forwarded arguments must cast to pointer types, which complicates debugging. This patch avoids those issues by aggregating captured arguments in a struct to pass to the fork_call.

Reviewed By: jdoerfert, jhuber6, ABataev

Differential Revision: https://reviews.llvm.org/D102107

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[OpenMP] Add loop tripcount argument to kernel launch and remove push function

Previously we added the `push_target_tripcount` function to send the
loop tripcount to the device runtime so we knew ho

[OpenMP] Add loop tripcount argument to kernel launch and remove push function

Previously we added the `push_target_tripcount` function to send the
loop tripcount to the device runtime so we knew how to configure the
teams / threads for execute the loop for a teams distribute construct.
This was implemented as a separate function mostly to avoid changing the
interface for backwards compatbility. Now that we've changed it anyway
and the new interface can take an arbitrary number of arguments via the
struct without changing the ABI, we can move this to the new interface.
This will simplify the runtime by removing unnecessary state between
calls.

Depends on D128550

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D128816

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[OpenMP] Change OpenMP code generation for target region entries

This patch changes the code we generate to enter a target region on the
device. This is in-line with the new definition in the runtim

[OpenMP] Change OpenMP code generation for target region entries

This patch changes the code we generate to enter a target region on the
device. This is in-line with the new definition in the runtime that was
added previously. Additionally we implement this in the OpenMPIRBuilder
so that this code can be shared with Flang in the future.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D128550

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