Changes

[Attributes] Clean up handling of UB implying attributes (NFC)

Rather than adding methods for dropping these attributes in
various places, add a function that returns an AttrBuilder with
these attributes, which can then be used with existing methods
for dropping attributes. This is with an eye on D104641, which
also needs to drop them from returns, not just parameters.

Also be more explicit about the semantics of the method in the
documentation. Refer to UB rather than Undef, which is what this
is actually about.

[X86][SSE] LowerRotate - perform modulo on the amount splat source directly.

If the rotation amount is a known splat, perform the modulo on the splat source, and then perform the splat. That way the amount-extension performed later by LowerScalarVariableShift can fold the splats away without any multiple-use issues.

Fixes one of the concerns raised on D104156

[OpenMP][tests][NFC] Update test status for gcc 11 and 12

gcc 11 introduced support for depend clause, but the gomp interface of libomp
does not yet handle the information.
Also remove -fopenmp-version=50, which is no longer needed for clang, but not
supported by gcc.

[AArch64] Fix Local Deallocation for Homogeneous Prolog/Epilog

The stack adjustment for local deallocation was incorrectly ported.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D106760

[NFC][Codegen][X86] Improve test coverage for insertions into XMM vector

[OpenMP] Introduce RAII to protect certain RTL calls from DCE

This patch introduces a new RAII struct that will temporarily make an OpenMP
RTL function have external linkage. This is done before the attributor is
invoked to prevent it from incorrectly removing some function definitions that
we will use later. For example, if we determine all calls to one function are
dead, because it has internal linkage it can safely be removed. Later when we
try to get an instance to that function to modify the source using
`getOrCreateRuntimeFunction` we will then get an empty declaration for that
function that won't be defined anywhere. This patch prevents this from
occurring.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106707

[libomptarget] Build amdgpu plugin without hsa

Default to building the amdgpu plugin to use dlopen when hsa is
not found instead of disabling it.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106600

[X86][AVX] Add getBROADCAST_LOAD helper function. NFCI.

Begin replacing individual getMemIntrinsicNode calls and setup (for X86ISD::VBROADCAST_LOAD + X86ISD::SUBV_BROADCAST_LOAD opcodes) with this getBROADCAST_LOAD helper.

[LangRef] Reorder two paragraphs for comdat

so that IMAGE_COMDAT_SELECT_LARGEST refers to the correct example.

Revert "[libomptarget] Build amdgpu plugin without hsa"

Inaccurate error handling around hsa_init

This reverts commit e30b3b23a4eddbc08b5648e643f0a0b456a57832.

Revert "[VPlan] Add recipe for first-order rec phis, make splicing explicit."

Makes clang crash: https://reviews.llvm.org/D105008#2903350
This reverts commit d2a73fb44ea0b8c981e4b923f811f18793fc4770.

Also revert a minor formatting follow-up:
This reverts commit 82834a673246f27a541ffcc57e0eb65b008102ef.

[docs] Update release notes to mention lli JIT engine switch

[lld/mac] Add tests for the interaction between -rename_section and -rename_segment

No behavior change.

Differential Revision: https://reviews.llvm.org/D106765

Revert "[lld/mac] Add tests for the interaction between -rename_section and -rename_segment"

This reverts commit a6eb34624dcfa5a33caa0211f4a16710b22079c2.
The test fails, I screwed something up.

[libomptarget][amdgpu] More robust handling of failure to init HSA

If hsa_init fails, subsequent calls into hsa are not safe. Except for
hsa_init, but we don't retry on failure.

This patch:
- deletes a print that called into hsa to ask why it can't call into hsa
- drops a merge conflict block next to that print
- reliably initializes number of devices to zero
- skips the plugin destructor contents if the constructor failed to init hsa

Tested by making hsa_init return error, and by forcing the dynamic library
use which was then deleted from disk. Before this patch, both segv. After it,
friendly message about offloading being unavailable.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106774

[lld/mac] Reland: Add tests for the interaction between -rename_section and -rename_segment

No behavior change.

Differential Revision: https://reviews.llvm.org/D106765

[lld/mac] Move output segment rename logic into OutputSegment

Fixes the output segment name if both -rename_section and
-rename_segment are used and the post-section-rename segment
name is the same as the pre-segment-rename segment name to
match ld64's behavior.

The motivation is that segment$start$ can create section-less segments,
and this makes a corner case in the interaction between segment$start and
-rename_segment in the upcoming segment$start patch.

Differential Revision: https://reviews.llvm.org/D106766

[lld/mac] Add support for segment$start$ and segment$end$ symbols

These symbols are somewhat interesting in that they create non-existing
segments, which as far as I know is the only way to create segments
that don't contain any sections.

Final part of part of PR50760. Like D106629, but for segments instead
of sections. I'm not aware of anything that needs this in practice.

Differential Revision: https://reviews.llvm.org/D106767

[lld/mac] Make comment style uniform in start-end.s test