Commit Graph

22 Commits

Author SHA1 Message Date
Johannes Doerfert b51b83f68e [Attributor] Introduce the concept of query AAs
D106720 introduced features that did not work properly as we could add
new queries after a fixpoint was reached and which could not be answered
by the information gathered up to the fixpoint alone.

As an alternative to D110078, which forced eager computation where we
want to continue to be lazy, this patch fixes the problem.

QueryAAs are AAs that allow lazy queries during their lifetime. They are
never fixed if they have no outstanding dependences and always run as
part of the updates in an iteration. To determine if we are done, all
query AAs are asked if they received new queries, if not, we only need
to consider updated AAs, as before. If new queries are present we go for
another iteration.

Differential Revision: https://reviews.llvm.org/D118669
2022-02-01 01:40:44 -06:00
Johannes Doerfert ac3ec22df9 [Attributor] Use AAFunctionReachability to determine AANoRecurse
We missed out on AANoRecurse in the module pass because we had no call
graph. With AAFunctionReachability we can simply ask if the function may
reach itself.

Differential Revision: https://reviews.llvm.org/D110099
2022-02-01 01:40:44 -06:00
Johannes Doerfert a1db0e523d [Attributor][FIX] Liveness handling in the isAssumedDead helpers
This fixes a conceptual problem with our AAIsDead usage which conflated
call site liveness with call site return value liveness. Without the
fix tests would obviously miscompile as we make genericValueTraversal
more powerful (in a follow up). The effects on the tests are mixed but
mostly marginal. The most prominent one is the lack of `noreturn` for
functions. The reason is that we make entire blocks live at the same
time (for time reasons). Now that we actually look at the block
liveness, which we need to do, the return instructions are live and
will survive. As an example,  `noreturn_async.ll` has been modified
to retain the `noreturn` even with block granularity. We could address
this easily but there is little need in practice.
2022-02-01 01:18:52 -06:00
Arthur Eubanks 096d9814aa [opt] Remove some legacy PM flags
Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D109664
2021-09-13 15:50:03 -07:00
Joseph Huber 97851a08e2 [Attributor] Don't test internalization in the CGSCC pass.
Summary:
Enabling internalization in the Attributor's CGSCC pass does something
different that we don't expect. Ignore this for now to pass the tests.
2021-07-28 19:15:23 -04:00
Johannes Doerfert d4bfce5521 [Attributor] Utilize the InstSimplify interface to simplify instructions
When we simplify at least one operand in the Attributor simplification
we can use the InstSimplify to work on the simplified operands. This
allows us to avoid duplication of the logic.

Depends on D106189

Differential Revision: https://reviews.llvm.org/D106190
2021-07-27 00:56:23 -05:00
Johannes Doerfert 5ef18e2421 [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 15:52:36 -05:00
Johannes Doerfert 5b12cf3e65 [Attributor][FIX] Traverse uses even if a value is assumed constant
Not all attributes are able to handle the interprocedural step and
follow the uses into a call site. Let them be able to combine call site
uses instead. This might result in some unused values/arguments being
leftover but it removes problems where we misused "is dead" even though
it was actually "is simplified/replaced".

We explicitly check for dead values due to constant propagation in
`AAIsDeadValueImpl::areAllUsesAssumedDead` instead.

Differential Revision: https://reviews.llvm.org/D103858
2021-07-10 15:47:20 -05:00
Nico Weber d3e7491333 Revert Attributor patch series
Broke check-clang, see https://reviews.llvm.org/D102307#2869065
Ran `git revert -n ebbe149a6f08535ede848a531a601ae6591cfbc5..269416d41908bb670f67af689155d5ab8eea689a`
2021-07-10 16:15:55 -04:00
Johannes Doerfert 374e573cfc [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 12:32:50 -05:00
Johannes Doerfert be5d46e9bb [Attributor][FIX] Traverse uses even if a value is assumed constant
Not all attributes are able to handle the interprocedural step and
follow the uses into a call site. Let them be able to combine call site
uses instead. This might result in some unused values/arguments being
leftover but it removes problems where we misused "is dead" even though
it was actually "is simplified/replaced".

We explicitly check for dead values due to constant propagation in
`AAIsDeadValueImpl::areAllUsesAssumedDead` instead.

Differential Revision: https://reviews.llvm.org/D103858
2021-07-10 12:32:49 -05:00
Johannes Doerfert fc82409b5c [Attributor] Simplify operands inside of simplification AAs first
When we do simplification via AAPotentialValues or AAValueConstantRange
we need to simplify the operands of an instruction we deconstruct first.
This does not only improve the result, see for example range.ll, but is
required as we allow outside AAs to provide simplification rules via
callbacks. If we do ignore the simplification rules and base other
simplifications on the IR instead we can create an inconsistent state.
2021-07-06 22:41:18 -05:00
Johannes Doerfert 666dc6f126 [Attributor] Use a centralized value simplification interface
To allow outside AAs that simplify values we need to ensure all value
simplification goes through the Attributor, not AAValueSimplify (or any
of the other AAs we have already like AAPotentialValues). This patch
also introduces an interface for the outside AAs to register
simplification callbacks for an IRPosition. To make this work as
expected we have to pass IRPositions instead of Values in
AAValueSimplify, which makes sense by itself.
2021-06-18 01:07:53 -05:00
Johannes Doerfert 9c2074dccb [Attributor][NFC] Update tests after D94741
The update_test_checks script can now check for global symbols and is able
to handle them properly when they differ across prefixes, e.g.,
attribute #0 might be different in different runs.

This patch simply updates all the Attributor tests with the new script.

Reviewed By: sstefan1

Differential Revision: https://reviews.llvm.org/D97906
2021-03-11 23:31:39 -06:00
Johannes Doerfert e592dad82e [Attributor] Fold "TrackDependence" into the DepClassTy enum
We don't need a bool and an enum to express the three options we
currently have. This makes the interface nicer and much easier to
use optional dependencies. Also avoids mistakes where the bool is
false and enum ignored.
2021-03-04 00:35:52 -06:00
Johannes Doerfert 3f540c05df [Attributor] Give up early on AANoReturn::initialize
If the function is not assumed `noreturn` we should not wait for an
update to mark the call site as "may-return".

This has two kinds of consequences:
  - We have less iterations in many tests.
  - We have less deductions based on "known information" (since we ask
    earlier, point 1, and therefore assumed information is not "known"
    yet).
The latter is an artifact that we might want to tackle properly at some
point but which is not easily fixable right now.
2020-10-06 19:31:07 -05:00
Johannes Doerfert 711bf7dcf9 [Attributor][FIX] Don't crash on internalizing linkonce_odr hidden functions
The CloneFunctionInto has implicit requirements with regards to the
linkage and visibility of the function. We now update these after we did
the CloneFunctionInto on the copy with the same linkage and visibility
as the original.
2020-09-07 23:38:09 -05:00
Johannes Doerfert 53e4ef7fc2 [Attributor][NFC] Cleanup internalize test case
One run line was different and probably introduced for the manually
added function attribute & name checks. We can do this with the script
and a check prefix used for the other run lines as well.
2020-09-07 23:38:09 -05:00
Shinji Okumura 7a15dfd056 [Attributor] Fix AANoUndef identification
Even though `noundef` IR attribute might be attached to non-void type values, AANoUndef is mistakenly identified for pointer type values only.
This patch fixes that.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86737
2020-08-30 05:39:25 +09:00
Shinji Okumura 835cfa5def [Attributor] Handle CallBase case in AAValueConstantRange::initialize
Currently, although we handle `CallBase` case in updateImpl, we give up in initialize in the case.
That is problematic when we propagate a range from call site returned position to floating position.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D86196
2020-08-20 20:15:19 +09:00
Johannes Doerfert 012819f301 [Attributor][FIX] Update the call graph properly when internalizing functions
The internal version is now part of the SCC, make sure to perform this
update.
2020-08-20 01:44:58 -05:00
Luofan Chen 87a85f3d57 [Attributor] Use internalized version of non-exact functions
This patch internalize non-exact functions and replaces of their uses
with the internalized version. Doing this enables the analysis of
non-exact functions.

We can do this because some non-exact functions with the same name
whose linkage is `linkonce_odr` or `weak_odr` should have the same
semantics, so we can safely internalize and replace use of them (the
result of the other version of this function should be the same.).
Note that not all functions can be internalized, e.g., function with
`linkonce` or `weak` linkage.

For now when specified in commandline, we internalize all functions
that meet the requirements without calculating the cost of such
internalzation.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D84167
2020-08-15 20:23:38 +08:00