[IR] Convert from nocapture to captures(none) (#123181)

This PR removes the old `nocapture` attribute, replacing it with the new
`captures` attribute introduced in #116990. This change is
intended

[IR] Convert from nocapture to captures(none) (#123181)

This PR removes the old `nocapture` attribute, replacing it with the new
`captures` attribute introduced in #116990. This change is
intended to be essentially NFC, replacing existing uses of `nocapture`
with `captures(none)` without adding any new analysis capabilities.
Making use of non-`none` values is left for a followup.

Some notes:
* `nocapture` will be upgraded to `captures(none)` by the bitcode
reader.
* `nocapture` will also be upgraded by the textual IR reader. This is to
make it easier to use old IR files and somewhat reduce the test churn in
this PR.
* Helper APIs like `doesNotCapture()` will check for `captures(none)`.
* MLIR import will convert `captures(none)` into an `llvm.nocapture`
attribute. The representation in the LLVM IR dialect should be updated
separately.

show more ...

[NFC][DebugInfo] Maintain RemoveDIs flag when attributor creates functions (#79143)

We're using this flag (IsNewDbgInfoFormat) to detect the boundaries in
LLVM of what's treating debug-info as intr

[NFC][DebugInfo] Maintain RemoveDIs flag when attributor creates functions (#79143)

We're using this flag (IsNewDbgInfoFormat) to detect the boundaries in
LLVM of what's treating debug-info as intrinsics (i.e. dbg.value), and
what's using DPValue objects (the non-intrinsic replacement). The
attributor tends to create new wrapper functions and doesn't insert them
into Modules in the usual way, thus we have to manually update that flag
to signal what debug-info mode it's using.

I've added some --try-experimental-debuginfo-iterators RUN lines to
tests that would otherwise crash because of this, so that they're
exercised by our new-debuginfo-iterators buildbot.

NB: there's an attributor test with a dbg.value in it, however
attributes re-order themselves in RemoveDIs mode for various reasons, so
we're going to address that in a different patch.

show more ...

[Attributor] Try to remove argmem effects after signature rewrite

If the new signature has only readnone pointers we can remove any argmem
effect from the function signature.

[Attributor] Manifest attributes implied by the IR

If an attribute is implied by the IR we do not (always) create an AA
anymore. To keep test coverage, and given the lack of a good heuristic
to deci

[Attributor] Manifest attributes implied by the IR

If an attribute is implied by the IR we do not (always) create an AA
anymore. To keep test coverage, and given the lack of a good heuristic
to decide otherwise, we will now also manifest such attributes.

show more ...

[Attributor] Check IR attributes before creating new AAs

Instead of creating an AA for an IR attribute we can first check if it
is implied/known. If so, we can save the time to create the AA, figure

[Attributor] Check IR attributes before creating new AAs

Instead of creating an AA for an IR attribute we can first check if it
is implied/known. If so, we can save the time to create the AA, figure
out it is implied, fix it, and later manifest it in the IR
(redundantly). Other IR attributes can be added to the list in
`AA::hasAssumedIRAttr` later on, for now we support 8 different ones.

show more ...

[Attributor] Remove the iteration count verification

It was never really useful to track #iterations, though it helped during
the initial development. What we should track, in a follow up, are
poten

[Attributor] Remove the iteration count verification

It was never really useful to track #iterations, though it helped during
the initial development. What we should track, in a follow up, are
potentially #updates. That is also what we should restrict instead of
the #iterations.

show more ...

[Attributor] Create `AAMustProgress` for the `mustprogress` attribute

Derive the mustprogress attribute based on the willreturn attribute
or the fact that all callers are mustprogress.

Differential

[Attributor] Create `AAMustProgress` for the `mustprogress` attribute

Derive the mustprogress attribute based on the willreturn attribute
or the fact that all callers are mustprogress.

Differential Revision: https://reviews.llvm.org/D94740

show more ...

[Attributor] Allow cfg reasoning for thread-local objects

If an object (=memory) is thread-local we do not need to worry about
threading effects.

[Attributor] Convert some tests to opaque pointers (NFC)

These were converted without adjustments.

[IR] Switch everything to use memory attribute

This switches everything to use the memory attribute proposed in
https://discourse.llvm.org/t/rfc-unify-memory-effect-attributes/65579.
The old argmemo

[IR] Switch everything to use memory attribute

This switches everything to use the memory attribute proposed in
https://discourse.llvm.org/t/rfc-unify-memory-effect-attributes/65579.
The old argmemonly, inaccessiblememonly and inaccessiblemem_or_argmemonly
attributes are dropped. The readnone, readonly and writeonly attributes
are restricted to parameters only.

The old attributes are auto-upgraded both in bitcode and IR.
The bitcode upgrade is a policy requirement that has to be retained
indefinitely. The IR upgrade is mainly there so it's not necessary
to update all tests using memory attributes in this patch, which
is already large enough. We could drop that part after migrating
tests, or retain it longer term, to make it easier to import IR
from older LLVM versions.

High-level Function/CallBase APIs like doesNotAccessMemory() or
setDoesNotAccessMemory() are mapped transparently to the memory
attribute. Code that directly manipulates attributes (e.g. via
AttributeList) on the other hand needs to switch to working with
the memory attribute instead.

Differential Revision: https://reviews.llvm.org/D135780

show more ...

[Attributor][NFC] Re-run update_test_checks on all Attributor tests

[Attribute] Clean up test prefixes (NFC)

Now that the legacy PM is no longer tested, the huge matrix of
test prefixes used by attributor tests is no longer needed and very
confusing for the casual r

[Attribute] Clean up test prefixes (NFC)

Now that the legacy PM is no longer tested, the huge matrix of
test prefixes used by attributor tests is no longer needed and very
confusing for the casual reader. Reduce the prefixes down to just
CHECK, TUNIT and CGSCC.

show more ...

[NFC][1/n] Remove -enable-new-pm=0 flags from lit tests

This is the first patch in a series intended for removing flag
-enable-new-pm=0 from lit tests. This is part of a bigger
effort of completely

[NFC][1/n] Remove -enable-new-pm=0 flags from lit tests

This is the first patch in a series intended for removing flag
-enable-new-pm=0 from lit tests. This is part of a bigger
effort of completely removing legacy code related to legacy
pass manager in favor of currently default new pass manager.

In this patch flag has been removed only from tests where no significant
change has been required because checks has been duplicated for
both PMs.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D134150

show more ...

[Attributor] Dominating must-write accesses allow unknown initial values

If we have a dominating must-write access we do not need to know the
initial value of some object to perform reasoning about

[Attributor] Dominating must-write accesses allow unknown initial values

If we have a dominating must-write access we do not need to know the
initial value of some object to perform reasoning about the potential
values. The dominating must-write has overwritten the initial value.

show more ...

[Attributor] Replace AAValueSimplify with AAPotentialValues

For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many

[Attributor] Replace AAValueSimplify with AAPotentialValues

For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many reasons:
- We recomputed the result a lot as there was no caching for the 9
locations calling `genericValueTraversal`.
- We added the idea of "intra" vs. "inter" procedural simplification
only as an afterthought. `genericValueTraversal` did offer an option
but `AAValueSimplify` did not. Thus, we might end up with "too much"
simplification in certain situations and then gave up on it.
- Because `genericValueTraversal` was not a real `AA` we ended up with
problems like the infinite recursion bug (#54981) as well as code
duplication.

This patch introduces `AAPotentialValues` and replaces the
`AAValueSimplify` uses with it. `genericValueTraversal` is folded into
`AAPotentialValues` as are the instruction simplifications performed in
`AAValueSimplify` before. We further distinguish "intra" and "inter"
procedural simplification now.

`AAValueSimplify` was not deleted as we haven't ported the
re-materialization of instructions yet. There are other differences over
the former handling, e.g., we may not fold trivially foldable
instructions right now, e.g., `add i32 1, 1` is not folded to `i32 2`
but if an operand would be simplified to `i32 1` we would fold it still.

We are also even more aware of function/SCC boundaries in CGSCC passes,
which is good even if some tests look like they regress.

Fixes: https://github.com/llvm/llvm-project/issues/54981

Note: A previous version was flawed and consequently reverted in
6555558a80589d1c5a1154b92cc3af9495f8f86c.

show more ...

Revert "[Attributor] Replace AAValueSimplify with AAPotentialValues"

This reverts commit f17639ea0cd30f52ac853ba2eb25518426cc3bb8 as three
AMDGPU tests haven't been updated. Will need to verify the

Revert "[Attributor] Replace AAValueSimplify with AAPotentialValues"

This reverts commit f17639ea0cd30f52ac853ba2eb25518426cc3bb8 as three
AMDGPU tests haven't been updated. Will need to verify the changes are
not regressions we should avoid.

show more ...

[Attributor] Replace AAValueSimplify with AAPotentialValues

For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many

[Attributor] Replace AAValueSimplify with AAPotentialValues

For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many reasons:
- We recomputed the result a lot as there was no caching for the 9
locations calling `genericValueTraversal`.
- We added the idea of "intra" vs. "inter" procedural simplification
only as an afterthought. `genericValueTraversal` did offer an option
but `AAValueSimplify` did not. Thus, we might end up with "too much"
simplification in certain situations and then gave up on it.
- Because `genericValueTraversal` was not a real `AA` we ended up with
problems like the infinite recursion bug (#54981) as well as code
duplication.

This patch introduces `AAPotentialValues` and replaces the
`AAValueSimplify` uses with it. `genericValueTraversal` is folded into
`AAPotentialValues` as are the instruction simplifications performed in
`AAValueSimplify` before. We further distinguish "intra" and "inter"
procedural simplification now.

`AAValueSimplify` was not deleted as we haven't ported the
re-materialization of instructions yet. There are other differences over
the former handling, e.g., we may not fold trivially foldable
instructions right now, e.g., `add i32 1, 1` is not folded to `i32 2`
but if an operand would be simplified to `i32 1` we would fold it still.

We are also even more aware of function/SCC boundaries in CGSCC passes,
which is good even if some tests look like they regress.

Fixes: https://github.com/llvm/llvm-project/issues/54981

Note: A previous version was flawed and consequently reverted in
6555558a80589d1c5a1154b92cc3af9495f8f86c.

show more ...

Revert "[Attributor] Replace AAValueSimplify with AAPotentialValues"

This reverts commit da50dab1ae111e9e6cb0248a47a038b17f798705.

Patch broke AMD GPU OpenMP offload buildbots.
https://lab.llvm.org

Revert "[Attributor] Replace AAValueSimplify with AAPotentialValues"

This reverts commit da50dab1ae111e9e6cb0248a47a038b17f798705.

Patch broke AMD GPU OpenMP offload buildbots.
https://lab.llvm.org/buildbot/#/builders/193/builds/13246

show more ...

[Attributor] Replace AAValueSimplify with AAPotentialValues

For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many

[Attributor] Replace AAValueSimplify with AAPotentialValues

For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many reasons:
- We recomputed the result a lot as there was no caching for the 9
locations calling `genericValueTraversal`.
- We added the idea of "intra" vs. "inter" procedural simplification
only as an afterthought. `genericValueTraversal` did offer an option
but `AAValueSimplify` did not. Thus, we might end up with "too much"
simplification in certain situations and then gave up on it.
- Because `genericValueTraversal` was not a real `AA` we ended up with
problems like the infinite recursion bug (#54981) as well as code
duplication.

This patch introduces `AAPotentialValues` and replaces the
`AAValueSimplify` uses with it. `genericValueTraversal` is folded into
`AAPotentialValues` as are the instruction simplifications performed in
`AAValueSimplify` before. We further distinguish "intra" and "inter"
procedural simplification now.

`AAValueSimplify` was not deleted as we haven't ported the
re-materialization of instructions yet. There are other differences over
the former handling, e.g., we may not fold trivially foldable
instructions right now, e.g., `add i32 1, 1` is not folded to `i32 2`
but if an operand would be simplified to `i32 1` we would fold it still.

We are also even more aware of function/SCC boundaries in CGSCC passes,
which is good.

Fixes: https://github.com/llvm/llvm-project/issues/54981

show more ...

[Attributor] CGSCC pass should not recompute results outside the SCC (reapply)

When we run the CGSCC pass we should only invest time on the SCC. We can
initialize AAs with information from the modul

[Attributor] CGSCC pass should not recompute results outside the SCC (reapply)

When we run the CGSCC pass we should only invest time on the SCC. We can
initialize AAs with information from the module slice but we should not
update those AAs. We make an exception for are call site of the SCC as
they are helpful providing information for the SCC.

Minor modifications to pointer privatization allow us to perform it even
in the CGSCC pass, similar to ArgumentPromotion.

show more ...

Revert "[Attributor] CGSCC pass should not recompute results outside the SCC"

This reverts commit 0d7f81e31315f8cda56ce6fde5ff5145e0325c51, it caused
the AMDGPU tests that use the Attributor to fail.

[Attributor] CGSCC pass should not recompute results outside the SCC

When we run the CGSCC pass we should only invest time on the SCC. We can
initialize AAs with information from the module slice bu

[Attributor] CGSCC pass should not recompute results outside the SCC

When we run the CGSCC pass we should only invest time on the SCC. We can
initialize AAs with information from the module slice but we should not
update those AAs.

show more ...

[Attributor] Cleanup manifest and liveness for CGSCC passes

There was some ad-hoc handling of liveness and manifest to avoid
breaking CGSCC guarantees. Things always slipped through though.
This cle

[Attributor] Cleanup manifest and liveness for CGSCC passes

There was some ad-hoc handling of liveness and manifest to avoid
breaking CGSCC guarantees. Things always slipped through though.
This cleanup will:

1) Prevent us from manifesting any "information" outside the CGSCC.
This might be too conservative but we need to opt-in to annotation
not try to avoid some problematic ones.
2) Avoid running any liveness analysis outside the CGSCC. We did have
some AAIsDeadFunction handling to this end but we need this for all
AAIsDead classes. The reason is that AAIsDead information is only
correct if we actually manifest it, since we don't (see point 1) we
cannot actually derive/use it at all. We are currently trying to
avoid running any AA updates outside the CGSCC but that seems to
impact things quite a bit.
3) Assert, don't check, that our modifications (during cleanup) modifies
only CGSCC functions.

show more ...

[Attributor][FIX] Reachability needs to account for readonly callees

The oversight caused us to ignore call sites that are effectively dead
when we computed reachability (or more precise the call ed

[Attributor][FIX] Reachability needs to account for readonly callees

The oversight caused us to ignore call sites that are effectively dead
when we computed reachability (or more precise the call edges of a
function). The problem is that loads in the readonly callee might depend
on stores prior to the callee. If we do not track the call edge we
mistakenly assumed the store before the call cannot reach the load.
The problem is nicely visible in:
`llvm/test/Transforms/Attributor/ArgumentPromotion/basictest.ll`

Caused by D118673.

Fixes https://github.com/llvm/llvm-project/issues/53726

show more ...

[Attributor] Introduce the `AA::isPotentiallyReachable` helper APIs

To make usage easier (compared to the many reachability related AAs),
this patch introduces a helper API, `AA::isPotentiallyReacha

[Attributor] Introduce the `AA::isPotentiallyReachable` helper APIs

To make usage easier (compared to the many reachability related AAs),
this patch introduces a helper API, `AA::isPotentiallyReachable`, which
performs all the necessary steps. It also does the "backwards"
reachability (see D106720) as that simplifies the AA a lot (backwards
queries were somewhat different from the other query resolvers), and
ensures we use cached values in every stage.

To test inter-procedural reachability in a reasonable way this patch
includes an extension to `AAPointerInfo::forallInterferingWrites`.
Basically, we can exclude writes if they cannot reach a load "during the
lifetime" of the allocation. That is, we need to go up the call graph to
determine reachability until we can determine the allocation would be
dead in the caller. This leads to new constant propagations (through
memory) in `value-simplify-pointer-info-gpu.ll`.

Note: The new code contains plenty debug output to determine how
reachability queries are resolved.

Parts extracted from D110078.

Differential Revision: https://reviews.llvm.org/D118673

show more ...