Summary:
Instead of building attributes for internal functions which we do not
update as long as we assume they are dead, we now do not create
attributes until we assume the internal function to be live. This
improves the number of required iterations, as well as the number of
required updates, in real code. On our tests, the results are mixed.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66914
llvm-svn: 370924
Summary:
We create attributes on-demand so we need to check the white list
on-demand. This also unifies the location at which we create,
initialize, and eventually invalidate new abstract attributes.
The tests show mixed results, a few more call site attributes are
determined which can cause more iterations.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66913
llvm-svn: 370922
Summary:
Before we tried to rule out non-exact definitions early but that lead to
on-demand attributes created for them anyway. As a consequence we needed
to look at the definition in the initialize of each attribute again.
This patch centralized this lookup and tightens the condition under
which we give up on non-exact definitions.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67115
llvm-svn: 370917
Add the no-capture argument attribute deduction to the Attributor
fixpoint framework.
The new string attributed "no-capture-maybe-returned" is introduced to
allow deduction of no-capture through functions that "capture" an
argument but only by "returning" it. It is only used by the Attributor
for testing.
Differential Revision: https://reviews.llvm.org/D59922
llvm-svn: 370817
Summary:
Instead of recomputing information for call sites we now use the
function information directly. This is always valid and once we have
call site specific information we can improve here.
This patch also bootstraps attributes that are created on-demand through
an initial update call. Information that is known will then directly be
available in the new attribute without causing an iteration delay.
The tests show how this improves the iteration count.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66781
llvm-svn: 370480
Summary:
Any pointer could have load/store users not only floating ones so we
move the manifest logic for alignment into the AAAlignImpl class.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66922
llvm-svn: 370479
As dependences between abstract attributes can become stale, e.g., if
one was sufficient to imply another one at some point but it has since
been wakened to the point it is not usable for the formerly implied one.
To weed out spurious dependences, and thereby eliminate unneeded
updates, we introduce an option to determine how often the dependence
cache is cleared and recomputed during the fixpoint iteration.
Note that the initial value was determined such that we see a positive
result on our tests.
Differential Revision: https://reviews.llvm.org/D63315
llvm-svn: 370230
Summary:
Until we have proper call-site information we should not recompute
liveness and return information for each call site. This patch directly
uses the function versions and introduces TODOs at the usage sites.
The required iterations to get to the fixpoint are most of the time
reduced by this change and we always avoid work duplication.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66562
llvm-svn: 370208
Summary:
During the fixpoint iteration, including the manifest stage, we should
not delete stuff as other abstract attributes might have a reference to
the value. Through the API this can now be done safely at the very end.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66779
llvm-svn: 370014
Summary:
Try to verify how many iterations we need for a fixpoint in our tests.
This patch adjust the way we count to make it easier to follow. It also
adjusts the bounds to actually account for a fixpoint and not only the
minimum number to pass all checks.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66757
llvm-svn: 369945
By default, the Attributor tracks potential dependences between abstract
attributes based on the issued Attributor::getAAFor queries. This
simplifies the development of new abstract attributes but it can also
lead to spurious dependences that might increase compile time and make
internalization harder (D63312). With this patch, abstract attributes
can opt-out of implicit dependence tracking and instead register
dependences explicitly. It is up to the implementation to make sure all
existing dependences are registered.
Differential Revision: https://reviews.llvm.org/D63314
llvm-svn: 369935
Summary:
We can now manifest alignment information in load/store instructions if
the pointer is known to have a better alignment.
Reviewers: uenoku, sstefan1, lebedev.ri
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66567
llvm-svn: 369804
Summary:
If the unique return value is a constant we now replace call uses with
that constant.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66551
llvm-svn: 369785
Summary:
If we have a loop in which the dereferenceability of a pointer decreases
we did slowly decrease it iteration by iteration, leading to a timeout.
With this patch we detect such circular reasoning and indicate a
fixpoint early.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66558
llvm-svn: 369784
Summary:
If we have a negative inbounds offset dereferenceabily "grows". However,
until we do not handle the overflow that can occur in the
dereferenceable bytes and the problem with loops, we simply do not grow
the state.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66557
llvm-svn: 369771
If the number of potentially returned values not change since the last
traversal we do not need to visit the returned values again. This works
as we only add values to the returned values set now.
Differential Revision: https://reviews.llvm.org/D66484
llvm-svn: 369770
Summary:
When we have new attributes and we end the fixpoint iteration because
the iteration limit is reached, we need to treat the new ones as if they
changed in the last iteration, as they might have.
This adds a test for which we should not derive anything regardless of
the iteration limit, e.g., if we abort there should not be any
attributes manifested in the IR.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66549
llvm-svn: 369768
Summary: In D65402, I want to get DerefState from AADereferenceable but it was not allowed. This patch moves DerefState definition into Attributor.h and makes AADerefenceable inherit StateWrapper.
Reviewers: jdoerfert, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66585
llvm-svn: 369653
For an internal function, if all its call sites are dead, the body of the function is considered dead.
Reviewers: jdoerfert, uenoku
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D66155
llvm-svn: 369470
Before, we create the set of abstract attributes initially and then
dealt with the fact hat a lookup could fail, e.g., return a nullptr.
This patch will ensure we always return a valid object from a lookup,
allowing us not only to remove the nullptr checks but also to grow the
set of abstract attributes "in-flight" on-demand.
One can now start from those that have the best chance of improving
performance without the need to specify all they might depend on.
While this introduces some boilerplate, the usage of attributes is much
easier and cleaner now.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66276
llvm-svn: 369331
Summary:
This is analogous to D66128 but for AADereferenceable. We have the logic
concentrated in the floating value updateImpl and we use the combiner
helper classes for arguments and return values.
The regressions will go away with "on-demand" attribute creation.
Improvements are already visible in the existing tests.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66272
llvm-svn: 369329
Summary:
What D66126 did for AAAlign, this patch does for AANonNull. Agian, the
logic becomes more concise and localized. Again, returned poiners are
not annotated properly but that will not be an issue if this lands with
the "on-demand" generation of attributes. First improvements due to the
genericValueTraversal are already visible.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66128
llvm-svn: 369328
The clamp operator should not take the known of the given state as the
known is potentially based on assumed information. This also adds TODOs
to guide improvements.
llvm-svn: 369327
This reverts commit b1752f670f3d6393306dd5d37546b6e23384d8a2.
Fixed the issue with a different commit, reapply this one as it was,
afaik, not broken.
llvm-svn: 369303
This reverts commit cedd0d9a6e4b433e1cd6585d1d4d152eb5e60b11.
Re-apply the original commit but make sure the variables are initialized
(even if they are not used) so UBSan is not complaining.
llvm-svn: 369294
This reverts r369159 (git commit cbaf1fdea2de891bdbc49cdec89ae2077e6b9ed0)
r369160 caused a test to fail under UBSAN. See thread on llvm-commits.
llvm-svn: 369241
This reverts r369160 (git commit f72d9b1c97b41fff48ad1eecbba59a29c171bff4)
r369160 caused some tests to fail under UBSAN. See thread on llvm-commits.
llvm-svn: 369236
By partially resolving returned calls we did not record that they were
not fully resolved which caused odd behavior down the line. We could
also end up with some, but not all, returned values of the callee in the
returned values map of the caller, another odd behavior we want to
avoid.
llvm-svn: 369160
As a preparation to "on-demand" abstract attribute generation we need
implementations for all attributes (as they can be queried and then
created on-demand where we now fail to find one).
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66129
llvm-svn: 369155
Summary:
This is the first commit aiming to structure the attribute deduction.
The base idea is that we have default propagation patterns as listed
below on top of which we can add specific, e.g., context sensitive,
logic.
Deduction patterns used in this patch:
- argument states are determined from call site argument states,
see AAAlignArgument and AAArgumentFromCallSiteArguments.
- call site argument states are determined as if they were floating
values, see AAAlignCallSiteArgument and AAAlignFloating.
- floating value states are determined by traversing the def-use chain
and combining the states determined for the leaves, see
AAAlignFloating and genericValueTraversal.
- call site return states are determined from function return states,
see AAAlignCallSiteReturned and AACallSiteReturnedFromReturned.
- function return states are determined from returned value states,
see AAAlignReturned and AAReturnedFromReturnedValues.
Through this strategy all logic for alignment is concentrated in the
AAAlignFloating::updateImpl method.
Note: This commit works on its own but is part of a larger change that
involves "on-demand" creation of abstract attributes that will
participate in the fixpoint iteration. Without this part, we sometimes
do not have an AAAlign abstract attribute to query, loosing information
we determined before. All tests have appropriate FIXMEs and the
information will be recovered once we added all parts.
Reviewers: sstefan1, uenoku
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66126
llvm-svn: 369144
Until we have call site specific liveness and/or value information there
is no need to do call site specific deduction. Though, we need the
symbols in follow up patches that make Attributor::getAAFor return a
reference.
llvm-svn: 369143
Summary:
This patch should not change the behavior except that the added
initialize methods might indicate an optimistic fixpoint earlier. The
code movement is done to keep the attribute definitions in a single
block where it makes sense. No functional changes intended there.
Reviewers: uenoku, sstefan1
Subscribers: hiraditya, bollu, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66258
llvm-svn: 369142
