[InstCombine] Preserve metadata from orig load in select fold. (#115605)

When replacing load with a select on the address with a select and 2
loads of the values, copy poison-generating metadata fr

[InstCombine] Preserve metadata from orig load in select fold. (#115605)

When replacing load with a select on the address with a select and 2
loads of the values, copy poison-generating metadata from the original
load to the newly created loads, which are placed at the same place as
the original loads. We cannot copy metadata that may trigger UB.

PR: https://github.com/llvm/llvm-project/pull/115605

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[InstCombine] Add extra metadata kinds to test.

Also clarify the FIXME, only none-UB metadata should be preserved.

Extra tests for https://github.com/llvm/llvm-project/pull/115605.

[Local] Only intersect alias.scope,noalias & parallel_loop if inst moves (#117716)

Preserve !alias.scope, !noalias and !mem.parallel_loop_access metadata
on the replacement instruction, if it does

[Local] Only intersect alias.scope,noalias & parallel_loop if inst moves (#117716)

Preserve !alias.scope, !noalias and !mem.parallel_loop_access metadata
on the replacement instruction, if it does not move. In that case, the
program would be UB, if the aliasing property encoded in the metadata
does not hold. This makes use of the clarification re aliasing metadata
implying UB if the property does not hold: #116220

Same as #115868, but for !alias.scope, !noalias and
!mem.parallel_loop_access.


PR: https://github.com/llvm/llvm-project/pull/117716

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[InstCombine] Add alias.scope & noalias metadata to test.

[Local] Only intersect tbaa metadata if instr moves. (#116682)

Preserve tbaa metadata on the replacement instruction, if it does not
move. In that case, the program would be UB, if the aliasing pro

[Local] Only intersect tbaa metadata if instr moves. (#116682)

Preserve tbaa metadata on the replacement instruction, if it does not
move. In that case, the program would be UB, if the aliasing property
encoded in the metadata does not hold.

This makes use of the clarification re tbaa metadata implying UB if the
property does not hold: https://github.com/llvm/llvm-project/pull/116220

Same as https://github.com/llvm/llvm-project/pull/115868, but for !tbaa

PR: https://github.com/llvm/llvm-project/pull/116682

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[Local] Only intersect llvm.access.group metadata if instr moves. (#115868)

Preserve llvm.access.group metadata on the replacement instruction, if
it does not move. In that case, the program would

[Local] Only intersect llvm.access.group metadata if instr moves. (#115868)

Preserve llvm.access.group metadata on the replacement instruction, if
it does not move. In that case, the program would be UB, if the parallel
property encoded in the metadata does not hold.

This matches the LangRef recently updated in #116220

PR https://github.com/llvm/llvm-project/pull/115868

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[InstCombine] Make access.group metadata tags distinct in test.

Make access.group metadata tags used in b56e03fccd distinct.

[InstCombine] Add extra test for preserving !llvm.access.group

Add variant with different metadata on all loads, for
https://github.com/llvm/llvm-project/pull/115868

[InstCombine] Add load/select test with noundef/invariant.load.

Further extends the test coverage added in 1aff96b3dfc with a load with
noundef and invariant.load metadata, which may trigger UB.

[InstCombine] Add extra tests for preserving load metadata.

Test cases for https://github.com/llvm/llvm-project/issues/115595.

[RFC] IR: Define noalias.addrspace metadata (#102461)

This is intended to solve a problem with lowering atomics in
OpenMP and C++ common to AMDGPU and NVPTX.

In OpenCL and CUDA, it is undefined

[RFC] IR: Define noalias.addrspace metadata (#102461)

This is intended to solve a problem with lowering atomics in
OpenMP and C++ common to AMDGPU and NVPTX.

In OpenCL and CUDA, it is undefined behavior for an atomic instruction
to modify an object in thread private memory. In OpenMP, it is defined.
Correspondingly, the hardware does not handle this correctly. For
AMDGPU,
32-bit atomics work and 64-bit atomics are silently dropped. We
therefore
need to codegen this by inserting a runtime address space check,
performing
the private case without atomics, and fallback to issuing the real
atomic
otherwise. This metadata allows us to avoid this extra check and branch.

Handle this by introducing metadata intended to be applied to atomicrmw,
indicating they cannot access the forbidden address space.

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[InstCombine] Canonicalize constant GEPs to i8 source element type (#68882)

This patch canonicalizes getelementptr instructions with constant
indices to use the `i8` source element type. This makes

[InstCombine] Canonicalize constant GEPs to i8 source element type (#68882)

This patch canonicalizes getelementptr instructions with constant
indices to use the `i8` source element type. This makes it easier for
optimizations to recognize that two GEPs are identical, because they
don't need to see past many different ways to express the same offset.

This is a first step towards
https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699.
This is limited to constant GEPs only for now, as they have a clear
canonical form, while we're not yet sure how exactly to deal with
variable indices.

The test llvm/test/Transforms/PhaseOrdering/switch_with_geps.ll gives
two representative examples of the kind of optimization improvement we
expect from this change. In the first test SimplifyCFG can now realize
that all switch branches are actually the same. In the second test it
can convert it into simple arithmetic. These are representative of
common optimization failures we see in Rust.

Fixes https://github.com/llvm/llvm-project/issues/69841.

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[InstCombine] Regenerate all test checks (NFC)

Due to an improvement to name preservation, a lot of InstCombine
tests now show spurious diffs when regenerated.

Rather than regenerating individual f

[InstCombine] Regenerate all test checks (NFC)

Due to an improvement to name preservation, a lot of InstCombine
tests now show spurious diffs when regenerated.

Rather than regenerating individual files when they get touched,
mass-regenerate all UTC-based InstCombine tests. I have then reset
a number of files showing suspicious diffs where the UTC output
has clearly been manually adjusted. I apologize if I missed
anything in the mass of changes.

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Fix test expected result [NFC]

Take 2
Aopologies for the noise. Metadata numbering doesn't seem to be stable..

Fix test expected result [NFC]

For some reason, it only fails on some buildbots, but not in all, and not on my computer..

[InstCombine] Fixup check lines in test (NFC)

These were broken by dfb0581bfa7b5fb9061876bd1b9af814408aaf95.

Fix !nonnull syntax in test [NFC]

[Local] Preserve noundef metadata in copyMetadataForLoad()

If we're only changing the type of the load, preserve the noundef
metadata.

[InstCombine] Add test for load type conversion with !noundef (NFC)

The !noundef metadata is currently dropped.

[test][InstCombine] Update some test cases to use opaque pointers

These tests cases were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34

Differential Re

[test][InstCombine] Update some test cases to use opaque pointers

These tests cases were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34

Differential Revision: https://reviews.llvm.org/D135094

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[test] Use -passes=instcombine instead of -instcombine in lots of tests. NFC

Another step moving away from the deprecated syntax of specifying
pass pipeline in opt.

Differential Revision: https://r

[test] Use -passes=instcombine instead of -instcombine in lots of tests. NFC

Another step moving away from the deprecated syntax of specifying
pass pipeline in opt.

Differential Revision: https://reviews.llvm.org/D119081

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[Tests] Fix incorrect noalias metadata

Mostly this fixes cases where !noalias or !alias.scope were passed
a scope rather than a scope list. In some cases I opted to drop
the metadata entirely instea

[Tests] Fix incorrect noalias metadata

Mostly this fixes cases where !noalias or !alias.scope were passed
a scope rather than a scope list. In some cases I opted to drop
the metadata entirely instead, because it is not really relevant
to the test.

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[InstCombine] Revert rL226781 "Teach InstCombine to canonicalize loads which are only ever stored to always use a legal integer type if one is available." (PR47592)

(it was introduced in https://lis

[InstCombine] Revert rL226781 "Teach InstCombine to canonicalize loads which are only ever stored to always use a legal integer type if one is available." (PR47592)

(it was introduced in https://lists.llvm.org/pipermail/llvm-dev/2015-January/080956.html)

This canonicalization seems dubious.

Most importantly, while it does not create `inttoptr` casts by itself,
it may cause them to appear later, see e.g. D88788.

I think it's pretty obvious that it is an undesirable outcome,
by now we've established that seemingly no-op `inttoptr`/`ptrtoint` casts
are not no-op, and are no longer eager to look past them.
Which e.g. means that given
```
%a = load i32
%b = inttoptr %a
%c = inttoptr %a
```
we likely won't be able to tell that `%b` and `%c` is the same thing.

As we can see in D88789 / D88788 / D88806 / D75505,
we can't really teach SCEV about this (not without the https://bugs.llvm.org/show_bug.cgi?id=47592 at least)
And we can't recover the situation post-inlining in instcombine.

So it really does look like this fold is actively breaking
otherwise-good IR, in a way that is not recoverable.
And that means, this fold isn't helpful in exposing the passes
that are otherwise unaware of these patterns it produces.

Thusly, i propose to simply not perform such a canonicalization.
The original motivational RFC does not state what larger problem
that canonicalization was trying to solve, so i'm not sure
how this plays out in the larger picture.

On vanilla llvm test-suite + RawSpeed, this results in
increase of asm instructions and final object size by ~+0.05%
decreases final count of bitcasts by -4.79% (-28990),
ptrtoint casts by -15.41% (-3423),
and of inttoptr casts by -25.59% (-6919, *sic*).
Overall, there's -0.04% less IR blocks, -0.39% instructions.

See https://bugs.llvm.org/show_bug.cgi?id=47592

Differential Revision: https://reviews.llvm.org/D88789

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[NFC][InstCombine] Autogenerate a few tests being affected by an upcoming patch

Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552