We can improve our deduction if we stop at PHI and select instructions
and also iterate the returned values explicitly. The latter helps with
isImpliedByIR deductions.
The very first AA, at least the first one in order, is not necessary
anymore. `AAReturnedValues` was from a different time; one might say, a
simpler time.
It was rewriten once to use `Attribute::getAssumedSimplifiedValues`,
which is what the replacement, `AAPotentialValuesReturned`, does too.
To match the old behavior we needed to avoid the helper
`AAReturnedFromReturnedValues` and iterate the return instructions
explicitly, however, it is still less complexity than it was before.
`AAReturnedFromReturnedValues` and `getAssumedSimplifiedValues` now
allow users to stop at PHI and select nodes or to ignore those and look
through. `AANoFPClass` will stop at select and phi nodes to read the
fast math flags.
Fixes: https://github.com/llvm/llvm-project/issues/63404
Differential Revision: https://reviews.llvm.org/D154917
If the function is non-IPO amendable we do skip most attributes/AAs.
However, if an AA has a isImpliedByIR that can deduce the attribute from
other attributes, we can run those. For now, we manually enable them,
if we have more later we can use some automation/flag.
This patch adds initial support for the `AAAddressSpace` abstract
attributor interface to deduce and query address space information for a
pointer. We simply query the underlying objects that a pointer can point
to and find a common address space if they exist. This is the minimal
support for the interface, we currently manifest changes on loads and
stores. Additionally we should use the target transform information to
deduce if an address space transformation is a no-op for the target
machine when calculating compatibility.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D120586
AANoCapture is now the first non-boolean AA that is always queried via
the new APIs and not created manually.
We explicitly do not manifest nocapture for `null` and `undef` anymore.
AANonNull is now the first AA that is always queried via the new APIs
and not created manually. Others will follow shortly to avoid trivial
AAs whenever possible.
This commit introduced some helper logic that will make it simpler to
port the next one. It also untangles AADereferenceable and AANonNull
such that the former does not keep a handle on the latter. Finally,
we stop deducing `nonnull` for `undef`, which was incorrect.
Before, we checked and manifested attributes right in the IR. This was
bad as we modified the IR before the manifest stage. Now we can
add/remove/inspect attributes w/o going to the IR (except for the
initial query).
We had some custom handling for existing MemoryEffects but we now move
it to the place we check other existing attributes before we manifest
new ones. If we later decide to curb duplication (of attributes on the
call site and callee), we can do that at a single location and for all
attributes.
The test changes basically add known `memory` callee information to the
call sites.
If the IR has a boolean attribute, or the function is not IPO amendable,
we can avoid creating AAs that would just be forced into a trivial
fixpoint anyway. Since we check boolean IR attributes via
`AA::hasAssumedIRAttr`, we don't need AAs even if they would be fixed
optimistic right away. The only change is in the dependency graph
ordering as we move AAs around to simplify the code flow. There is no
reason for the order we seed AAs, so this order is just as fine.
While we can disallow AAs, liveness checks are everywhere and if the
user doesn't want them it is costly to go through just to find out
everything is assumed live.
We now consistently use `CallBase::getCalledOperand` rather than
`getCalledFunction`, as we do not want the type checked performed by the
latter. This exposed various missing checks to handle mismatches
properly, but it is good to have them explicit now.
In a follow up we might want to flag certain calls as UB, but for now,
we allow everything to cut down on unexpected differences.
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.
For a lightweight pass we do not want to instantiate or use the
MustBeExecutedContextExplorer. This simply allows such a configuration.
While at it, the explorer is now allocated with the bump allocator.
Derive the mustprogress attribute based on the willreturn attribute
or the fact that all callers are mustprogress.
Differential Revision: https://reviews.llvm.org/D94740
AS(4), when targeting GPUs, is constant. Accesses to constant memory are
(historically) not treated as "memory accesses", hence we should deduce
`memory(none)` for those.
Currently we don't check call backs for global variable simplification.
What's more, the only way that we can register a simplification call back for
global variable is through its initializer (essentially a `Constant *`). It might
not correspond to the right global variable. In this patch, we set up a dedicated
simplification map for `GlobalVariable`.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D144749
This patch adds the AANonConvergent abstract attribute. It removes the
convergent attribute from functions that only call non-convergent
functions.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D143228
When we simplify loads we need to adjust types (esp. null-values)
properly to avoid inconsinstencies down the line. Add a cast and an
error message.
Fixes: https://github.com/llvm/llvm-project/issues/60788
We know kernels (generally) cannot be called from within the module. Thus,
for reachability we would need to step back from a kernel which would allow
us to reach anything anyway. Even if a kernel is invoked from another
kernel, values like allocas and shared memory are not accessible. We
implicitly check for this situation to avoid costly lookups.
We used to check the query instructions for effects but that does not
work well with complex accesses we will probably support in the future.
Now we simply let the user decide what accesses to look for.
With this patch we track aligned barriers in AAExecutionDomain and also
delete unnecessary barriers there. This allows us to eliminate barriers
across blocks, across functions, and in the presence of complex accesses
that do not force a barrier. Further, we can use the collected
information to enable store-load forwarding in a threaded environment
(follow up patch).
Differential Revision: https://reviews.llvm.org/D140463
