Changes

[AMDGPU] Consider all SGPR uses as unique in constant bus verify

Fix the verifier so that overlapping SGPR operands are counted
independently.  We cannot assume that overlapping SGPR accesses
only count as a single constant bus use.
The exception is implicit uses which do not add to constant bus
usage (only) when overlapping.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D87748

[NFC] Remove unnecessary default constructors

[GlobalISel][AMDGPU] Lower G_SMULH/G_UMULH

Reviewed By: arsenm, foad

Differential Revision: https://reviews.llvm.org/D85653

[lld-macho] Initial support for common symbols

On Unix, it is traditionally allowed to write variable definitions without
initialization expressions (such as "int foo;") to header files. These are
called tentative definitions.

The compiler creates common symbols when it sees tentative definitions. When
linking the final binary, if there are remaining common symbols after name
resolution is complete, the linker converts them to regular defined symbols in
a `__common` section.

This diff implements most of that functionality, though we do not yet handle
the case where there are both common and non-common definitions of the same
symbol.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D86909

[lld-macho] Implement and test resolution of common symbols

Handle the case where there are both common and non-common definitions
of the same symbol. Add a bunch of tests to ensure compatibility with ld64.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D86910

[lld-macho] Emit indirect symbol table

Makes it a little easier to read objdump's disassembly.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D87178

[lld-macho] Ignore `-mllvm` and its argument

Test Plan:

Reviewed By: #lld-macho, compnerd, MaskRay

Differential Revision: https://reviews.llvm.org/D87803

[lld-macho] Support -weak_lx, -weak_library, -weak_framework

They cause their corresponding libraries / frameworks to be loaded via
`LC_LOAD_WEAK_DYLIB` instead of `LC_LOAD_DYLIB`.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D87929

[lld-macho][NFC] Refactor syslibroot / library path lookup

* Move computation of systemLibraryRoots into a separate function, so we
  can add more functionality to it without things becoming unwieldy
* Have `getSearchPaths` and related functions return by value instead of
  by output parameter. NRVO should ensure that performance is unaffected.

Reviewed By: #lld-macho, smeenai

Differential Revision: https://reviews.llvm.org/D87959

[lld-macho][NFC] Make `!= nullptr` implicit

[IRSim] Adding structural comparison to IRSimilarityCandidate.

Just because sequences of instructions are similar to one another,
doesn't mean they are doing the same thing.

This introduces a structural check for the IRSimilarityCandidate that
compares two IRSimilarityCandidates against one another, and in each
instruction creates a mapping between the operands and results, or
checks that the existing mapping is valid.  If this check passes, it
means we have structurally similar IRSimilarityCandidates.

Tests for whether the candidates are found in
unittests/Analysis/IRSimilarityIdentifierTest.cpp.

Revert "[IRSim] Adding structural comparison to IRSimilarityCandidate."

This reverts commit b27db2bb68163fa5bcb4a8f631a305eb5adb44e5.

[IRSim] Adding structural comparison to IRSimilarityCandidate.

Just because sequences of instructions are similar to one another,
doesn't mean they are doing the same thing.

This introduces a structural check for the IRSimilarityCandidate that
compares two IRSimilarityCandidates against one another, and in each
instruction creates a mapping between the operands and results, or
checks that the existing mapping is valid.  If this check passes, it
means we have structurally similar IRSimilarityCandidates.

Tests for whether the candidates are found in
unittests/Analysis/IRSimilarityIdentifierTest.cpp.

Recommit of: b27db2bb68163fa5bcb4a8f631a305eb5adb44e5 for Differential
URL.

Differential Revision: https://reviews.llvm.org/D86971

[Power10]  Implement custom codegen for the vec_replace_elt and vec_replace_unaligned builtins.

This patch implements custom codegen for the vec_replace_elt and
vec_replace_unaligned builtins.

These builtins map to the @llvm.ppc.altivec.vinsw and @llvm.ppc.altivec.vinsd
intrinsics depending on the arguments. The main motivation for doing custom
codegen for these intrinsics is because there are float and double versions of
the builtin. Normally, the converting the float to an integer would be done via
fptoui in the IR. This is incorrect as fptoui truncates the value and we must
ensure the value is not truncated. Therefore, we provide custom codegen to utilize
bitcast instead as bitcasts do not truncate.

Differential Revision: https://reviews.llvm.org/D83500