The current splitting algorithm works in three stages:
1) Identify cold blocks, then
2) Use forward/backward propagation to mark hot blocks, then
3) Grow a SESE region of blocks *outside* of the set of hot blocks and
start outlining.
While testing this pass on Apple internal frameworks I noticed that some
kinds of control flow (e.g. loops) are never outlined, even though they
unconditionally lead to / follow cold blocks. I noticed two other issues
related to how cold regions are identified:
- An inconsistency can arise in the internal state of the hotness
propagation stage, as a block may end up in both the ColdBlocks set
and the HotBlocks set. Further inconsistencies can arise as these sets
do not match what's in ProfileSummaryInfo.
- It isn't necessary to limit outlining to single-exit regions.
This patch teaches the splitting algorithm to identify maximal cold
regions and outline them. A maximal cold region is defined as the set of
blocks post-dominated by a cold sink block, or dominated by that sink
block. This approach can successfully outline loops in the cold path. As
a side benefit, it maintains less internal state than the current
approach.
Due to a limitation in CodeExtractor, blocks within the maximal cold
region which aren't dominated by a single entry point (a so-called "max
ancestor") are filtered out.
Results:
- X86 (LNT + -Os + externals): 134KB of TEXT were outlined compared to
47KB pre-patch, or a ~3x improvement. Did not see a performance impact
across two runs.
- AArch64 (LNT + -Os + externals + Apple-internal benchmarks): 149KB
of TEXT were outlined. Ditto re: performance impact.
- Outlining results improve marginally in the internal frameworks I
tested.
Follow-ups:
- Outline more than once per function, outline large single basic
blocks, & try to remove unconditional branches in outlined functions.
Differential Revision: https://reviews.llvm.org/D53627
llvm-svn: 345209
In this patch, I'm adding an extra check to the Latch's terminator in llvm::UnrollRuntimeLoopRemainder,
similar to how it is already done in the llvm::UnrollLoop.
The compiler would crash if this function is called with a malformed loop.
Patch by Rodrigo Caetano Rocha!
Differential Revision: https://reviews.llvm.org/D51486
llvm-svn: 342958
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@
The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.
Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
and access to them.
* PassInstrumentation class that handles instrumentation-point interfaces
that call into PassInstrumentationCallbacks.
* Callbacks accept StringRef which is just a name of the Pass right now.
There were some ideas to pass an opaque wrapper for the pointer to pass instance,
however it appears that pointer does not actually identify the instance
(adaptors and managers might have the same address with the pass they govern).
Hence it was decided to go simple for now and then later decide on what the proper
mental model of identifying a "pass in a phase of pipeline" is.
* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
on different IRUnits (e.g. Analyses).
* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
usual AnalysisManager::getResult. All pass managers were updated to run that
to get PassInstrumentation object for instrumentation calls.
* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
args out of a generic PassManager's extra args. This is the only way I was able to explicitly
run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
RepeatedPass::run.
TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
and then get rid of getAnalysisResult by improving RepeatedPass implementation.
* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
PassInstrumentationAnalysis. Callbacks registration should be performed directly
through PassInstrumentationCallbacks.
* new-pm tests updated to account for PassInstrumentationAnalysis being run
* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.
Made getName helper to return std::string (instead of StringRef initially) to fix
asan builtbot failures on CGSCC tests.
Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858
llvm-svn: 342664
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@
The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.
Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
and access to them.
* PassInstrumentation class that handles instrumentation-point interfaces
that call into PassInstrumentationCallbacks.
* Callbacks accept StringRef which is just a name of the Pass right now.
There were some ideas to pass an opaque wrapper for the pointer to pass instance,
however it appears that pointer does not actually identify the instance
(adaptors and managers might have the same address with the pass they govern).
Hence it was decided to go simple for now and then later decide on what the proper
mental model of identifying a "pass in a phase of pipeline" is.
* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
on different IRUnits (e.g. Analyses).
* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
usual AnalysisManager::getResult. All pass managers were updated to run that
to get PassInstrumentation object for instrumentation calls.
* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
args out of a generic PassManager's extra args. This is the only way I was able to explicitly
run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
RepeatedPass::run.
TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
and then get rid of getAnalysisResult by improving RepeatedPass implementation.
* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
PassInstrumentationAnalysis. Callbacks registration should be performed directly
through PassInstrumentationCallbacks.
* new-pm tests updated to account for PassInstrumentationAnalysis being run
* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.
Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858
llvm-svn: 342597
Summary:
Pass Execution Instrumentation interface enables customizable instrumentation
of pass execution, as per "RFC: Pass Execution Instrumentation interface"
posted 06/07/2018 on llvm-dev@
The intent is to provide a common machinery to implement all
the pass-execution-debugging features like print-before/after,
opt-bisect, time-passes etc.
Here we get a basic implementation consisting of:
* PassInstrumentationCallbacks class that handles registration of callbacks
and access to them.
* PassInstrumentation class that handles instrumentation-point interfaces
that call into PassInstrumentationCallbacks.
* Callbacks accept StringRef which is just a name of the Pass right now.
There were some ideas to pass an opaque wrapper for the pointer to pass instance,
however it appears that pointer does not actually identify the instance
(adaptors and managers might have the same address with the pass they govern).
Hence it was decided to go simple for now and then later decide on what the proper
mental model of identifying a "pass in a phase of pipeline" is.
* Callbacks accept llvm::Any serving as a wrapper for const IRUnit*, to remove direct dependencies
on different IRUnits (e.g. Analyses).
* PassInstrumentationAnalysis analysis is explicitly requested from PassManager through
usual AnalysisManager::getResult. All pass managers were updated to run that
to get PassInstrumentation object for instrumentation calls.
* Using tuples/index_sequence getAnalysisResult helper to extract generic AnalysisManager's extra
args out of a generic PassManager's extra args. This is the only way I was able to explicitly
run getResult for PassInstrumentationAnalysis out of a generic code like PassManager::run or
RepeatedPass::run.
TODO: Upon lengthy discussions we agreed to accept this as an initial implementation
and then get rid of getAnalysisResult by improving RepeatedPass implementation.
* PassBuilder takes PassInstrumentationCallbacks object to pass it further into
PassInstrumentationAnalysis. Callbacks registration should be performed directly
through PassInstrumentationCallbacks.
* new-pm tests updated to account for PassInstrumentationAnalysis being run
* Added PassInstrumentation tests to PassBuilderCallbacks unit tests.
Other unit tests updated with registration of the now-required PassInstrumentationAnalysis.
Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D47858
llvm-svn: 342544
These classes don't make any changes to IR and have no reason to be in
Transform/Utils. This patch moves them to Analysis folder. This will allow
us reusing these classes in some analyzes, like MustExecute.
llvm-svn: 341015
This is a bit awkward in a handful of places where we didn't even have
an instruction and now we have to see if we can build one. But on the
whole, this seems like a win and at worst a reasonable cost for removing
`TerminatorInst`.
All of this is part of the removal of `TerminatorInst` from the
`Instruction` type hierarchy.
llvm-svn: 340701
In the past, DbgInfoIntrinsic has a strong assumption that these
intrinsics all have variables and expressions attached to them.
However, it is too strong to derive the class for other debug entities.
Now, it has problems for debug labels.
In order to make DbgInfoIntrinsic as a base class for 'debug info', I
create a class for 'variable debug info', DbgVariableIntrinsic.
DbgDeclareInst, DbgAddrIntrinsic, and DbgValueInst will be derived from it.
Differential Revision: https://reviews.llvm.org/D50220
llvm-svn: 338984
Summary:
Previously, `removeUnreachableBlocks` still returns true (which indicates the CFG is changed) even when all the unreachable blocks found is awaiting deletion in the DDT class.
This makes code pattern like
```
// Code modified from lib/Transforms/Scalar/SimplifyCFGPass.cpp
bool EverChanged = removeUnreachableBlocks(F, nullptr, DDT);
...
do {
EverChanged = someMightHappenModifications();
EverChanged |= removeUnreachableBlocks(F, nullptr, DDT);
} while (EverChanged);
```
become a dead loop.
Fix this by detecting whether a BasicBlock is already awaiting deletion.
Reviewers: kuhar, brzycki, dmgreen, grosser, davide
Reviewed By: kuhar, brzycki
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49738
llvm-svn: 338882
Summary:
This patch is the second in a series of patches related to the [[ http://lists.llvm.org/pipermail/llvm-dev/2018-June/123883.html | RFC - A new dominator tree updater for LLVM ]].
It converts passes (e.g. adce/jump-threading) and various functions which currently accept DDT in local.cpp and BasicBlockUtils.cpp to use the new DomTreeUpdater class.
These converted functions in utils can accept DomTreeUpdater with either UpdateStrategy and can deal with both DT and PDT held by the DomTreeUpdater.
Reviewers: brzycki, kuhar, dmgreen, grosser, davide
Reviewed By: brzycki
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48967
llvm-svn: 338814
The patch introduces loop analysis (VPLoopInfo/VPLoop) for VPBlockBases.
This analysis will be necessary to perform some H-CFG transformations and
detect and introduce regions representing a loop in the H-CFG.
Reviewers: fhahn, rengolin, mkuper, hfinkel, mssimpso
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D48816
llvm-svn: 338346
The patch introduces dominator analysis for VPBlockBases and extend
VPlan's GraphTraits specialization with the required interfaces. Dominator
analysis will be necessary to perform some H-CFG transformations and
to introduce VPLoopInfo (LoopInfo analysis on top of the VPlan representation).
Reviewers: fhahn, rengolin, mkuper, hfinkel, mssimpso
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D48815
llvm-svn: 338310
Memory leaks in tests.
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/6289/steps/check-llvm%20asan/logs/stdio
Direct leak of 192 byte(s) in 1 object(s) allocated from:
#0 0x554ea8 in operator new(unsigned long) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:106
#1 0x56cef1 in llvm::VPlanTestBase::doAnalysis(llvm::Function&) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h:53:14
#2 0x56bec4 in llvm::VPlanTestBase::buildHCFG(llvm::BasicBlock*) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h:57:3
#3 0x571f1e in llvm::(anonymous namespace)::VPlanHCFGTest_testVPInstructionToVPRecipesInner_Test::TestBody() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp:119:15
#4 0xed2291 in testing::Test::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
#5 0xed44c8 in testing::TestInfo::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2656:11
#6 0xed5890 in testing::TestCase::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2774:28
#7 0xef3634 in testing::internal::UnitTestImpl::RunAllTests() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:4649:43
#8 0xef27e0 in testing::UnitTest::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
#9 0xebbc23 in RUN_ALL_TESTS /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/include/gtest/gtest.h:2233:46
#10 0xebbc23 in main /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/UnitTestMain/TestMain.cpp:51
#11 0x7f65569592e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
and more.
llvm-svn: 336718
This patch introduces a VPValue in VPBlockBase to represent the condition
bit that is used as successor selector when a block has multiple successors.
This information wasn't necessary until now, when we are about to introduce
outer loop vectorization support in VPlan code gen.
Reviewers: fhahn, rengolin, mkuper, hfinkel, mssimpso
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D48814
llvm-svn: 336554
The replaceAllDbgUsesWith utility helps passes preserve debug info when
replacing one value with another.
This improves upon the existing insertReplacementDbgValues API by:
- Updating debug intrinsics in-place, while preventing use-before-def of
the replacement value.
- Falling back to salvageDebugInfo when a replacement can't be made.
- Moving the responsibiliy for rewriting llvm.dbg.* DIExpressions into
common utility code.
Along with the API change, this teaches replaceAllDbgUsesWith how to
create DIExpressions for three basic integer and pointer conversions:
- The no-op conversion. Applies when the values have the same width, or
have bit-for-bit compatible pointer representations.
- Truncation. Applies when the new value is wider than the old one.
- Zero/sign extension. Applies when the new value is narrower than the
old one.
Testing:
- check-llvm, check-clang, a stage2 `-g -O3` build of clang,
regression/unit testing.
- This resolves a number of mis-sized dbg.value diagnostics from
Debugify.
Differential Revision: https://reviews.llvm.org/D48676
llvm-svn: 336451
This reverts commit f976cf4cca0794267f28b54e468007fd476d37d9.
I am reverting this because it causes break in a few bots and its going
to take me sometime to look at this.
llvm-svn: 334993
Summary:
Simplify blockaddress usage before giving up in MergeBlockIntoPredecessor
This is a missing small optimization in MergeBlockIntoPredecessor.
This helps with one simplifycfg test which expects this case to be handled.
Reviewers: davide, spatel, brzycki, asbirlea
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48284
llvm-svn: 334992
This patch introduces a VPInstructionToVPRecipe transformation, which
allows us to generate code for a VPInstruction based VPlan re-using the
existing infrastructure.
Reviewers: dcaballe, hsaito, mssimpso, hfinkel, rengolin, mkuper, javed.absar, sguggill
Reviewed By: dcaballe
Differential Revision: https://reviews.llvm.org/D46827
llvm-svn: 334969
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)
llvm-svn: 333954
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
Reapply the patches with a fix. Thanks Ilya and Hans for the reproducer!
This reverts commit r330416.
The issue was that removing predecessors invalidated uses that we stored
for rewrite. The fix is to finish manipulating with CFG before we select
uses for rewrite.
llvm-svn: 330431
Revert r330413: "[SSAUpdaterBulk] Use SmallVector instead of DenseMap for storing rewrites."
Revert r330403 "Reapply "[PR16756] Use SSAUpdaterBulk in JumpThreading." one more time."
r330403 commit seems to crash clang during our integrate while doing PGO build with the following stacktrace:
#2 llvm::SSAUpdaterBulk::RewriteAllUses(llvm::DominatorTree*, llvm::SmallVectorImpl<llvm::PHINode*>*)
#3 llvm::JumpThreadingPass::ThreadEdge(llvm::BasicBlock*, llvm::SmallVectorImpl<llvm::BasicBlock*> const&, llvm::BasicBlock*)
#4 llvm::JumpThreadingPass::ProcessThreadableEdges(llvm::Value*, llvm::BasicBlock*, llvm::jumpthreading::ConstantPreference, llvm::Instruction*)
#5 llvm::JumpThreadingPass::ProcessBlock(llvm::BasicBlock*)
The crash happens while compiling 'lib/Analysis/CallGraph.cpp'.
r3340413 is reverted due to conflicting changes.
llvm-svn: 330416
Summary:
SSAUpdater is a bottleneck in a number of passes, and one of the reasons
is that it performs a lot of unnecessary computations (DT/IDF) over and
over again. This patch adds a new SSAUpdaterBulk that uses existing DT
and avoids recomputing IDF when possible.
Reviewers: dberlin, davide, MatzeB
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D44282
llvm-svn: 329643
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
In case PredBB == BB and StopAt == BB's terminator, StopAt != &*BI will
fail, because BB's terminator instruction gets replaced.
By using BB.getTerminator() we get the current terminator which we can use
to compare.
Reviewers: sanjoy, anna, reames
Reviewed By: anna
Differential Revision: https://reviews.llvm.org/D43822
llvm-svn: 326779
In stage2 -O3 builds of llc, this results in small but measurable
increases in the number of variables with locations, and in the number
of unique source variables overall.
(According to llvm-dwarfdump --statistics, there are 123 additional
variables with locations, which is just a 0.006% improvement).
The size of the .debug_loc section of the llc dsym increases by 0.004%.
llvm-svn: 326629
In stage2 -O3 builds of llc, this results in a 0.3% increase in the
number of variables with locations, and a 0.2% increase in the number of
unique source variables overall.
The size of the .debug_loc section of the llc dsym increases by 0.5%.
llvm-svn: 326621
Removes verifyDomTree, using assert(verify()) everywhere instead, and
changes verify a little to always run IsSameAsFreshTree first in order
to print good output when we find errors. Also adds verifyAnalysis for
PostDomTrees, which will allow checking of PostDomTrees it the same way
we check DomTrees and MachineDomTrees.
Differential Revision: https://reviews.llvm.org/D41298
llvm-svn: 326315
With my bad luck I separately implemented the DomTree preservation
for ConstantFoldTerminator before r322401 was committed. Commit the
tests which I think still provide some value.
llvm-svn: 322683
We were not doing that for large shadow granularity. Also add more
stack frame layout tests for large shadow granularity.
Differential Revision: https://reviews.llvm.org/D39475
llvm-svn: 318581
Summary: For some irreducible CFG the domtree nodes might be dead, do not update domtree for dead nodes.
Reviewers: kuhar, dberlin, hfinkel
Reviewed By: kuhar
Subscribers: llvm-commits, mcrosier
Differential Revision: https://reviews.llvm.org/D38960
llvm-svn: 316582
Summary:
If the extracted region has multiple exported data flows toward the same BB which is not included in the region, correct resotre instructions and PHI nodes won't be generated inside the exitStub. The solution is simply put the restore instructions right after the definition of output values instead of putting in exitStub.
Unittest for this bug is included.
Author: myhsu
Reviewers: chandlerc, davide, lattner, silvas, davidxl, wmi, kuhar
Subscribers: dberlin, kuhar, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D37902
llvm-svn: 315041
Vedant Kumar