Move TargetRegistry.(h|cpp) from Support to MC

This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually us

Move TargetRegistry.(h|cpp) from Support to MC

This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454

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[SelectionDAG] Replace error prone index check in BaseIndexOffset::computeAliasing

Deriving NoAlias based on having the same index in two BaseIndexOffset
expressions seemed weird (and as shown in th

[SelectionDAG] Replace error prone index check in BaseIndexOffset::computeAliasing

Deriving NoAlias based on having the same index in two BaseIndexOffset
expressions seemed weird (and as shown in the added unittest the
correctness of doing so depended on undocumented pre-conditions that
the user of BaseIndexOffset::computeAliasing would need to take care
of.

This patch removes the code that dereived NoAlias based on indices
being the same. As a compensation, to avoid regressions/diffs in
various lit test, we also add a new check. The new check derives
NoAlias in case the two base pointers are based on two different
GlobalValue:s (neither of them being a GlobalAlias).

Reviewed By: niravd

Differential Revision: https://reviews.llvm.org/D110256

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[SelectionDAG] Assume that a GlobalAlias may alias other global values

This fixes a bug detected in DAGCombiner when using global alias
variables. Here is an example:
@foo = global i16 0, align 1

[SelectionDAG] Assume that a GlobalAlias may alias other global values

This fixes a bug detected in DAGCombiner when using global alias
variables. Here is an example:
@foo = global i16 0, align 1
@aliasFoo = alias i16, i16 * @foo
define i16 @bar() {
...
store i16 7, i16 * @foo, align 1
store i16 8, i16 * @aliasFoo, align 1
...
}

BaseIndexOffset::computeAliasing would incorrectly derive NoAlias
for the two accesses in the example above, resulting in DAGCombiner
miscompiles.

This patch fixes the problem by a defensive approach letting
BaseIndexOffset::computeAliasing return false, i.e. that the aliasing
couldn't be determined, when comparing two global values and at least
one is a GlobalAlias. In the future we might improve this with a
deeper analysis to look at the aliasee for the GlobalAlias etc. But
that is a bit more complicated considering that we could have
'local_unnamed_addr' and situations with several 'alias' variables.

Fixes PR51878.

Differential Revision: https://reviews.llvm.org/D110064

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[unittests][CodeGen] Mark tests that cannot be executed with GTEST_SKIP()

This helps to distinguish such tests from successfully passed ones.

Differential Revision: https://reviews.llvm.org/D102754

[SelectionDAG] Don't pass a scalable vector to MachinePointerInfo::getWithOffset in a unit test.

Suppresses an implicit TypeSize to uint64_t conversion warning.

We might be able to just not offset

[SelectionDAG] Don't pass a scalable vector to MachinePointerInfo::getWithOffset in a unit test.

Suppresses an implicit TypeSize to uint64_t conversion warning.

We might be able to just not offset it since we're writing to a
Fixed stack object, but I wasn't sure so I just did what
DAGTypeLegalizer::IncrementPointer does.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D98736

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[SelectionDAG] Avoid aliasing analysis if the object size is unknown.

If the size of memory access is unknown, do not use it to analysis. One
example of unknown size memory access is to load/store s

[SelectionDAG] Avoid aliasing analysis if the object size is unknown.

If the size of memory access is unknown, do not use it to analysis. One
example of unknown size memory access is to load/store scalable vector
objects on the stack.

Differential Revision: https://reviews.llvm.org/D91833

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