Changes

[RISCV] Support simple fractional steps in matching VID sequences

This patch extends the optimization of VID-sequence BUILD_VECTORs
introduced in D104921 to include simple fractional steps composed of a
separated integer numerator and denominator.

A notable limitation in this sequence detection is that only sequences
with steps N/1 or 1/D are found, meaning that the step between elements
and the frequency with which it changes is consistent across the whole
sequence. Fractional steps such as 2/3 won't be matched as those would
involve more complex tracking of state or some level of backtracking.

As is stands, however, this patch is sufficient to match common
interleave-type shuffle indices, for example matching `<0,0,1,1>` (or
commonly `<0,u,1,u>` or `<u,0,u,1>`) to an index sequence divided by 2.

While the optimization is relatively `undef`-tolerant, due to greedy
pattern-matching there even are some simple patterns which confuse the
sequence detection into identifying either a suboptimal sequence or no
sequence at all.

Currently only fractional-step sequences identified as having a
power-of-two denominator are actually lowered to RVV instructions. This
is to avoid introducing divisions into the generated code.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D106533

[MLIR][OpenMP] Add support for critical construct

This patch adds the critical construct to the OpenMP dialect. The
implementation models the definition in 2.17.1 of the OpenMP 5 standard.
A name and hint can be specified. The name is a global entity or has
external linkage, it is modelled as a FlatSymbolRefAttr. Hint is
modelled as an integer enum attribute.
Also lowering to LLVM IR using the OpenMP IRBuilder.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D107135

[clang] Make member var invalid when static initializer is invalid.

Previously we would show an error, but keep the member, and also the
CXXRrecordDecl, valid. This could lead to crashes when attempting to
access the record layout or size.

Differential Revision: https://reviews.llvm.org/D105478

tsan: use Tid/StackID types in MBlock

Replace more raw types with Tid/StackID typedefs.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D107335

[libc] Allow benchmarking several implementations at the same time.

Next step is to generate an archive with all implementations and a header listing them all.

Differential Revision: https://reviews.llvm.org/D107336

[llvm-objcopy] IHexELFBuilder::addDataSections - fix evaluation ordering static analyzer warning

As detailed on https://pvs-studio.com/en/blog/posts/cpp/0771/ and raised on D62583, the SecNo++ increment is not guaranteed to occur before the second use of SecNo in the same addSection() call.

This patch pulls out the increment (just for clarity) and replaces the second use of SecNo with a constant zero value (we're using stable_sort so the value isn't critical).

Differential Revision: https://reviews.llvm.org/D107273

Make simple requirements starting with requires ill-formed in in requirement body

This patch implements P2092

Simple requirements in requirement body shall not start with requires.
A warning was already in place so we just turn this warning into an error.

In addition, we add tests to make sure typename is optional in
requirement-parameter-list as per the same paper.

tsan: use semaphores for thread creation synchronization

We currently use ad-hoc spin waiting to synchronize thread creation
and thread start both ways. But spinning tend to degrade ungracefully
under high contention (lots of threads are created at the same time).
Use semaphores for synchronization instead.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D107337

[X86] Add title comment to separate the "CPU Families" features from the other subtarget features. NFCI.

Hopefully we can get rid of these some day...

This feature is not in Clang 13 and only has partial support

[InstCombine] Remove nnan requirement for transformation to fabs from select

In this patch, the "nnan" requirement is removed for the canonicalization of select with fcmp to fabs.
(i) FSub logic: Remove check for nnan flag presence in fsub. Example: https://alive2.llvm.org/ce/z/751svg (fsub).
(ii) FNeg logic: Remove check for the presence of nnan and nsz flag in fneg. Example: https://alive2.llvm.org/ce/z/a_fsdp (fneg).

Differential Revision: https://reviews.llvm.org/D106872

[InstCombine] Fold phi ( inttoptr/ptrtoint x ) to phi (x)

The inttoptr/ptrtoint roundtrip optimization is not always correct.
We are working towards removing this optimization and adding support to specific cases where this optimization works.

In this patch, we focus on phi-node operands with inttoptr casts.
We know that ptrtoint( inttoptr( ptrtoint x) ) is same as ptrtoint (x).
So, we want to remove this roundtrip cast which goes through phi-node.

Reviewed By: aqjune

Differential Revision: https://reviews.llvm.org/D106289

Revert "[InstCombine] Remove nnan requirement for transformation to fabs from select"

This reverts commit 6180ce2e2abeb6f1f1b57852773ea07b8be290fa.

[OpenMP] libomp: taskwait depend implementation fixed.

Fix for https://bugs.llvm.org/show_bug.cgi?id=49723.
Eliminated references from task dependency hash to node allocated on stack,
thus eliminated accesses to stale memory. So the node now never freed.
Uncommented assertion which triggered when stale memory accessed.
Removed unneeded ref count increment for stack allocated node.

Differential Revision: https://reviews.llvm.org/D106705

[DAG] Cleanup DAGCombiner::CombineConsecutiveLoads early-outs. NFCI.

We had some similar hasOneUse/isNON_EXTLoad early-outs spread out over different parts of the method - we should pull them all together.

Noticed while triaging PR45116

[mlir][CPURunner] Avoid a crash in memrefCopy when called with empty shapes.

Differential Revision: https://reviews.llvm.org/D107346