Added two flags to omit uncommon or dead paths in the CFG graphs:
-cfg-hide-unreachable-paths
-cfg-hide-deoptimize-paths
The main purpose is performance analysis when such block are not
"interesting" from perspective of common path performance.
Reviewed By: apilipenko, davidxl
Differential Revision: https://reviews.llvm.org/D74346
Summary:
There is a flaw in memory dependence analysis caching mechanism when memory accesses with TBAA are involved. Assume we first analysed and cached results for access with TBAA. Later we request dependence for the same memory but without TBAA (or different TBAA). By design these two queries should share one entry in the internal cache which corresponds to a general access (without TBAA). Thus upon second request internal cached is cleared and we continue analysis for access as if there is no TBAA.
The problem is that even though internal cache is cleared the set of visited nodes is not. That means we won't traverse visited nodes again and populate internal cache with the corresponding dependence results. So we end up with internal cache in an incomplete state. Current implementation tries to signal that situation by resetting CacheInfo->Pair at line 1104. But that doesn't actually help since later code ignores this invalidation and relies on 'Cache->empty()' property to decide on cache completeness.
Reviewers: reames, hfinkel, chandlerc, fedor.sergeev, asbirlea, fhahn, john.brawn, Prazek, sunfish
Reviewed By: john.brawn
Subscribers: DaniilSuchkov, kosarev, jfb, dantrushin, hiraditya, bmahjour, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73032
Summary:
As mentioned in D71974, it is useful for must-be-executed-context to explore CFG backwardly.
This patch is ported from parts of D64975. We use a dominator tree to find the previous context if
a dominator tree is available.
Reviewers: jdoerfert, hfinkel, baziotis, sstefan1
Reviewed By: jdoerfert
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74817
Summary:
This is the last functional patch affecting the representation of DDG.
Here we try to simplify the DDG to reduce the number of nodes and edges by
iteratively merging pairs of nodes that satisfy the following conditions,
until no such pair can be identified. A pair of nodes consisting of a and b
can be merged if:
1. the only edge from a is a def-use edge to b and
2. the only edge to b is a def-use edge from a and
3. there is no cyclic edge from b to a and
4. all instructions in a and b belong to the same basic block and
5. both a and b are simple (single or multi instruction) nodes.
These criteria allow us to fold many uninteresting def-use edges that
commonly exist in the graph while avoiding the risk of introducing
dependencies that didn't exist before.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto, ppc-slack
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72350
isKnownNonNaN() could not recognize a zero splat because that is a
ConstantAggregateZero which is-a ConstantData but not a ConstantDataVector.
Patch makes a ConstantAggregateZero return true.
Review: Thomas Lively
Differential Revision: https://reviews.llvm.org/D74263
After having committed https://reviews.llvm.org/D72226, 2 buildbots
running GCC 5.4.0 began failing. The cause was the order in which those
compilers evaluated the left- and right-hand sides of the expression
`RC.SCCIndices[C] = RC.SCCIndices.size();`. This commit splits the
expression into multiple statements to avoid ambiguity, and adds a test
case that exercises the code that caused the test failures on those
older compilers (which was originally included in the reviewed patch,
https://reviews.llvm.org/D72226).
Essentially, fold OrderedBasicBlock into BasicBlock, and make it
auto-invalidate the instruction ordering when new instructions are
added. Notably, we don't need to invalidate it when removing
instructions, which is helpful when a pass mostly delete dead
instructions rather than transforming them.
The downside is that Instruction grows from 56 bytes to 64 bytes. The
resulting LLVM code is substantially simpler and automatically handles
invalidation, which makes me think that this is the right speed and size
tradeoff.
The important change is in SymbolTableTraitsImpl.h, where the numbering
is invalidated. Everything else should be straightforward.
We probably want to implement a fancier re-numbering scheme so that
local updates don't invalidate the ordering, but I plan for that to be
future work, maybe for someone else.
Reviewed By: lattner, vsk, fhahn, dexonsmith
Differential Revision: https://reviews.llvm.org/D51664
Relative to the original commit, this fixes some warnings,
and is based on the deletion of the IRBuilder copy constructor
in D74693. The automatic copy constructor would no longer be
safe.
-----
Related llvm-dev thread:
http://lists.llvm.org/pipermail/llvm-dev/2020-February/138951.html
This patch moves the IRBuilder from templating over the constant
folder and inserter towards making both of these virtual.
There are a couple of motivations for this:
1. It's not possible to share code between use-sites that use
different IRBuilder folders/inserters (short of templating the code
and moving it into headers).
2. Methods currently defined on IRBuilderBase (which is not templated)
do not use the custom inserter, resulting in subtle bugs (e.g.
incorrect InstCombine worklist management). It would be possible to
move those into the templated IRBuilder, but...
3. The vast majority of the IRBuilder implementation has to live
in the header, because it depends on the template arguments.
4. We have many unnecessary dependencies on IRBuilder.h,
because it is not easy to forward-declare. (Significant parts of
the backend depend on it via TargetLowering.h, for example.)
This patch addresses the issue by making the following changes:
* IRBuilderDefaultInserter::InsertHelper becomes virtual.
IRBuilderBase accepts a reference to it.
* IRBuilderFolder is introduced as a virtual base class. It is
implemented by ConstantFolder (default), NoFolder and TargetFolder.
IRBuilderBase has a reference to this as well.
* All the logic is moved from IRBuilder to IRBuilderBase. This means
that methods can in the future replace their IRBuilder<> & uses
(or other specific IRBuilder types) with IRBuilderBase & and thus
be usable with different IRBuilders.
* The IRBuilder class is now a thin wrapper around IRBuilderBase.
Essentially it only stores the folder and inserter and takes care
of constructing the base builder.
What this patch doesn't do, but should be simple followups after this change:
* Fixing use of the inserter for creation methods originally defined
on IRBuilderBase.
* Replacing IRBuilder<> uses in arguments with IRBuilderBase, where useful.
* Moving code from the IRBuilder header to the source file.
From the user perspective, these changes should be mostly transparent:
The only thing that consumers using a custom inserted may need to do is
inherit from IRBuilderDefaultInserter publicly and mark their InsertHelper
as public.
Differential Revision: https://reviews.llvm.org/D73835
Summary:
Depends on https://reviews.llvm.org/D70927.
`LazyCallGraph::addNewFunctionIntoSCC` allows users to insert a new
function node into a call graph, into a specific, existing SCC.
Extend this interface such that functions can be added even when they do
not belong in any existing SCC, but instead in a new SCC within an
existing RefSCC.
The ability to insert new functions as part of a RefSCC is necessary for
outlined functions that do not form a strongly connected cycle with the
function they are outlined from. An example of such a function would be the
coroutine funclets 'f.resume', etc., which are outlined from a coroutine 'f'.
Coroutine 'f' only references the funclets' addresses, it does not call
them directly.
Reviewers: jdoerfert, chandlerc, wenlei, hfinkel
Reviewed By: jdoerfert
Subscribers: hfinkel, JonChesterfield, mehdi_amini, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72226
Related llvm-dev thread:
http://lists.llvm.org/pipermail/llvm-dev/2020-February/138951.html
This patch moves the IRBuilder from templating over the constant
folder and inserter towards making both of these virtual.
There are a couple of motivations for this:
1. It's not possible to share code between use-sites that use
different IRBuilder folders/inserters (short of templating the code
and moving it into headers).
2. Methods currently defined on IRBuilderBase (which is not templated)
do not use the custom inserter, resulting in subtle bugs (e.g.
incorrect InstCombine worklist management). It would be possible to
move those into the templated IRBuilder, but...
3. The vast majority of the IRBuilder implementation has to live
in the header, because it depends on the template arguments.
4. We have many unnecessary dependencies on IRBuilder.h,
because it is not easy to forward-declare. (Significant parts of
the backend depend on it via TargetLowering.h, for example.)
This patch addresses the issue by making the following changes:
* IRBuilderDefaultInserter::InsertHelper becomes virtual.
IRBuilderBase accepts a reference to it.
* IRBuilderFolder is introduced as a virtual base class. It is
implemented by ConstantFolder (default), NoFolder and TargetFolder.
IRBuilderBase has a reference to this as well.
* All the logic is moved from IRBuilder to IRBuilderBase. This means
that methods can in the future replace their IRBuilder<> & uses
(or other specific IRBuilder types) with IRBuilderBase & and thus
be usable with different IRBuilders.
* The IRBuilder class is now a thin wrapper around IRBuilderBase.
Essentially it only stores the folder and inserter and takes care
of constructing the base builder.
What this patch doesn't do, but should be simple followups after this change:
* Fixing use of the inserter for creation methods originally defined
on IRBuilderBase.
* Replacing IRBuilder<> uses in arguments with IRBuilderBase, where useful.
* Moving code from the IRBuilder header to the source file.
From the user perspective, these changes should be mostly transparent:
The only thing that consumers using a custom inserted may need to do is
inherit from IRBuilderDefaultInserter publicly and mark their InsertHelper
as public.
Differential Revision: https://reviews.llvm.org/D73835
Summary:
This is second attempt to fix the problem with incorrect dependencies reported in presence of invariant load. Initial fix (https://reviews.llvm.org/D64405) was reverted due to a regression reported in https://reviews.llvm.org/D70516.
The original fix changed caching behavior for invariant loads. Namely such loads are not put into the second level cache (NonLocalDepInfo). The problem with that fix is the first level cache (CachedNonLocalPointerInfo) still works as if invariant loads were in the second level cache. The solution is in addition to not putting dependence results into the second level cache avoid putting info about invariant loads into the first level cache as well.
Reviewers: jdoerfert, reames, hfinkel, efriedma
Reviewed By: jdoerfert
Subscribers: DaniilSuchkov, hiraditya, bmahjour, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73027
MemorySSA is often taking up an unreasonable fraction of runtime in
assertion enabled builds. Turns out that there is one code-path that
runs verifyMemorySSA() even if VerifyMemorySSA is not enabled. This
patch makes it conditional as well.
Differential Revision: https://reviews.llvm.org/D74505
Summary:
This was a very odd API, where you had to pass a flag into a zext
function to say whether the extended bits really were zero or not. All
callers passed in a literal true or false.
I think it's much clearer to make the function name reflect the
operation being performed on the value we're tracking (rather than on
the KnownBits Zero and One fields), so zext means the value is being
zero extended and new function anyext means the value is being extended
with unknown bits.
NFC.
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74482
Summary:
Bail out early for scalable vectors. As global variables are not expected
to be scalable.
Use explicit call of getFixedSize() to assert on places where scalable size
doesn't make sense.
Reviewers: sdesmalen, efriedma, apazos, huntergr, willlovett
Reviewed By: sdesmalen
Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74424
Summary:
Passes ORE, BPI, BFI are not being preserved by Loop passes, hence it
is incorrect to retrieve these passes as cached.
This patch makes the loop passes in question compute a new instance.
In some of these cases, however, it may be beneficial to change the Loop pass to
a Function pass instead, similar to the change for LoopUnrollAndJam.
Reviewers: chandlerc, dmgreen, jdoerfert, reames
Subscribers: mehdi_amini, hiraditya, zzheng, steven_wu, dexonsmith, Whitney, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72891
With the fixed implementation of the "remainder" operation in
rG9d0956ebd471, we can now add support to folding calls to it.
Differential Revision: https://reviews.llvm.org/D69777
Summary:
Part of the changes in D44564 made BasicAA not CFG only due to it using
PhiAnalysisValues which may have values invalidated.
Subsequent patches (rL340613) appear to have addressed this limitation.
BasicAA should not be invalidated by non-CFG-altering passes.
A concrete example is MemCpyOpt which preserves CFG, but we are testing
it invalidates BasicAA.
llvm-dev RFC: https://groups.google.com/forum/#!topic/llvm-dev/eSPXuWnNfzM
Reviewers: john.brawn, sebpop, hfinkel, brzycki
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74353
LoopCacheAnalysis currently assumes the loop will be iterated over in
a forward direction. This patch addresses the issue by using the
absolute value of the stride when iterating backwards.
Note: this patch will treat negative and positive array access the
same, resulting in the same cost being calculated for single and
bi-directional access patterns. This should be improved in a
subsequent patch.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D73064
The CallGraphUpdater is a helper that simplifies the process of updating
the call graph, both old and new style, while running an CGSCC pass.
The uses are contained in different commits, e.g. D70767.
More functionality is added as we need it.
Reviewed By: modocache, hfinkel
Differential Revision: https://reviews.llvm.org/D70927
Bionic has had `__strlen_chk` for a while. Optimizing that into a
constant is quite profitable, when possible.
Differential Revision: https://reviews.llvm.org/D74079
If we know that a >= b (unsigned), usub.with.overflow(a, b) cannot
overflow. Similarly, if b > a, the same expression overflows.
Reviewers: nikic, RKSimon, lebedev.ri, spatel
Reviewed By: nikic, Gerolf
Differential Revision: https://reviews.llvm.org/D74066
This patch adds versions of isImpliedCondition and
isImpliedByDomCondition that take a predicate, LHS and RHS operands as
instead of a Value representing the condition.
This allows using those functions to check conditions without having a
concrete ICmp instruction.
Reviewers: nikic, RKSimon, lebedev.ri, spatel
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D74065
I was debug stepping through an x86 shuffle lowering and
noticed we were doing an N^2 search for splat index. I
didn't find the equivalent functionality anywhere else in
LLVM, so here's a helper that takes an array of int and
returns a splatted index while ignoring undefs (any
negative value).
This might also be used inside existing
ShuffleVectorInst/ShuffleVectorSDNode functions and/or
help with D72467.
Differential Revision: https://reviews.llvm.org/D74064
Summary:
It can be useful to tune the default inline threshold without overriding other inlining thresholds (e.g. in code compiled for size).
The existing `-inline-threshold` flag overrides other thresholds, so it is insufficient in codebases where there is a mix of code compiled for size and speed.
Patch by Michael Holman <michael.holman@microsoft.com>
Reviewers: eraman, tejohnson
Reviewed By: tejohnson
Subscribers: tejohnson, mtrofin, davidxl, hiraditya, haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73217
Summary:
Add a debug check for frequency queries for unknown blocks (typically blocks
that are created after BFI is computed but their frequencies are not
communicated to BFI.)
This is useful for detecting and debugging missed BFI updates.
This is debug build only and disabled behind a flag.
Reviewers: davidxl
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73920
ClangBuildAnalyzer results show that a lot of time is spent
instantiating AnalysisManager::getResultImpl across the code base:
**** Templates that took longest to instantiate:
50445 ms: llvm::AnalysisManager<llvm::Function>::getResultImpl (412 times, avg 122 ms)
47797 ms: llvm::AnalysisManager<llvm::Function>::getResult<llvm::TargetLibraryAnalysis> (389 times, avg 122 ms)
46894 ms: std::tie<const unsigned long long, const bool> (2452 times, avg 19 ms)
43851 ms: llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, 4096, 4096>::Allocate (3228 times, avg 13 ms)
33911 ms: std::tie<const unsigned int, const unsigned int, const unsigned int, const unsigned int> (897 times, avg 37 ms)
33854 ms: std::tie<const unsigned long long, const unsigned long long> (1897 times, avg 17 ms)
27886 ms: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string (11156 times, avg 2 ms)
I mentioned this result to @chandlerc, and he suggested this direction.
AnalysisManager is already explicitly instantiated, and getResultImpl
doesn't need to be inlined. Move the definition to an Impl header, and
include that header in files that explicitly instantiate
AnalysisManager. There are only four (real) IR units:
- function
- module
- loop
- cgscc
Looking at a specific transform (ArgumentPromotion.cpp), here are three
compilations before & after this change:
BEFORE:
$ for i in $(seq 3) ; do ./ccit.bat ; done
peak memory: 258.15MB
real: 0m6.297s
peak memory: 257.54MB
real: 0m5.906s
peak memory: 257.47MB
real: 0m6.219s
AFTER:
$ for i in $(seq 3) ; do ./ccit.bat ; done
peak memory: 235.35MB
real: 0m5.454s
peak memory: 234.72MB
real: 0m5.235s
peak memory: 234.39MB
real: 0m5.469s
The 20MB of memory saved seems real, and the time improvement seems like
it is there.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D73817
Summary:
* Most of the simplifications in SimplifyShuffleVectorInst depend on the
concrete value of, or the length of the mask vector. For scalable
vectors, this cannot be known at compile time.
** for these tests, detect if the vector is scalable before attempting
the transformation
* The functions ShuffleVectorInst::getMaskValue and
ShuffleVectorInst::getShuffleMask access the value of the constant mask.
However, since the length of the mask is unknown at compile time, these
function do not work for scalable vectors. Add asserts to ensure that
the input mask is not scalable
Reviewers: efriedma, sdesmalen, apazos, chrisj, huihuiz
Reviewed By: efriedma
Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73555
With this patch new trivial edges can be added to an SCC in a CGSCC
pass via the updateCGAndAnalysisManagerForCGSCCPass method. It shares
almost all the code with the existing
updateCGAndAnalysisManagerForFunctionPass method but it implements the
first step towards the TODOs.
This was initially part of D70927.
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D72025
We want to allow splat value transforms to improve PR44588 and related bugs:
https://bugs.llvm.org/show_bug.cgi?id=44588
...but to do that, we need to know if values are splatted from the same,
specific index (lane) rather than splatted from an arbitrary index.
We can improve the undef handling with 1-liner follow-ups because the
Constant API optionally allow undefs now.
Differential Revision: https://reviews.llvm.org/D73549
This patch adds initial support for a DemandedElts mask to the internal computeKnownBits/ComputeNumSignBits methods, matching the SelectionDAG and GlobalISel equivalents.
So far only a couple of instructions have been setup to handle the DemandedElts, the remainder still using the existing 'all elements' default. The plan is to extend support as we have test coverage.
Differential Revision: https://reviews.llvm.org/D73435
Summary:
This patch makes sure that the field VFShape.VF is greater than zero
when demangling the vector function name of scalable vector functions
encoded in the "vector-function-abi-variant" attribute.
This change is required to be able to provide instances of VFShape
that can be used to query the VFDatabase for the vectorization passes,
as such passes always require a positive value for the Vectorization Factor (VF)
needed by the vectorization process.
It is not possible to extract the value of VFShape.VF from the mangled
name of scalable vector functions, because it is encoded as
`x`. Therefore, the VFABI demangling function has been modified to
extract such information from the IR declaration of the vector
function, under the assumption that _all_ vectors in the signature of
the vector function have the same number of lanes. Such assumption is
valid because it is also assumed by the Vector Function ABI
specifications supported by the demangling function (x86, AArch64, and
LLVM internal one).
The unit tests that demangle scalable names have been modified by
adding the IR module that carries the declaration of the vector
function name being demangled.
In particular, the demangling function fails in the following cases:
1. When the declaration of the scalable vector function is not
present in the module.
2. When the value of VFSHape.VF is not greater than 0.
Reviewers: jdoerfert, sdesmalen, andwar
Reviewed By: jdoerfert
Subscribers: mgorny, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73286
Summary:
It is called when instructions aren't simplified, and the implementation
is expected to account for a penalty. Renamed to
onCommonInstructionMissedSimplification.
Reviewers: davidxl, eraman
Reviewed By: davidxl
Subscribers: hiraditya, baloghadamsoftware, haicheng, a.sidorin, Szelethus, donat.nagy, dkrupp, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73662
Summary:
This will help with devirtualization (store forwarding with vtable pointers in
the presence of other stores into members in the constructor.) During inlining,
we don't have AA.
Reviewers: davidxl
Subscribers: mgorny, Prazek, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71307
Previously, the enums didn't account for all the possible cases, which
could cause misleading results (particularly for a "switch" on
FunctionModRefBehavior).
Fixes regression in polly from recent patch to add writeonly to memset.
While I'm here, also fix a few dubious uses of the FMRB_* enum values.
Differential Revision: https://reviews.llvm.org/D73154
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
Kirill Naumov