Commit Graph

375203 Commits

Author SHA1 Message Date
Cullen Rhodes 1fd3a04775 [LV] Disable epilogue vectorization for scalable VFs
Epilogue vectorization doesn't support scalable vectorization factors
yet, disable it for now.

Reviewed By: sdesmalen, bmahjour

Differential Revision: https://reviews.llvm.org/D93063
2020-12-17 12:14:03 +00:00
Simon Pilgrim 2d6b1e9b5f [DebugInfo] Fix MSVC build by adding back necessary reverse_iterator != operator
Put back the std::reverse_iterator<DWARFDie::iterator> != operator that was removed in D78938 to fix VS2019 builds
2020-12-17 12:06:44 +00:00
Sam McCall 894c4761c6 [clangd] Add llvm:: qualifier to work around GCC bug. NFC
Some old GCC versions seem to miss the default template parameter when
using the clang/Basic/LLVM.h forward declarations of SmallVector.

See D92788
2020-12-17 12:51:12 +01:00
Kerry McLaughlin 7c504b6dd0 [AArch64] Renamed sve-masked-scatter-legalise.ll. NFC. 2020-12-17 11:40:09 +00:00
Martin Storsjö 08a00c6f43 [libcxx] Remove ifdefs in the message to static_assert. NFC.
Differential Revision: https://reviews.llvm.org/D93283
2020-12-17 13:37:52 +02:00
Alex Zinenko ccdd8c7759 [mlir] Move LLVM Dialect Op documentation to ODS
This was long overdue. The initial documentation for the LLVM dialect was
introduced before ODS had support for long descriptions. This is now possible,
so the documentation is moved to ODS, which can serve as a single source of
truth. The high-level description of the dialect structure is updated to
reflect that.

Depends On: D93315

Reviewed By: rriddle, mehdi_amini

Differential Revision: https://reviews.llvm.org/D93425
2020-12-17 12:32:35 +01:00
Alex Zinenko c2751250f3 [mlir] partially update LLVM dialect documentation
Rewrite the parts of the documentation that became stale: context/module
handling and type system. Expand the type system description.

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D93315
2020-12-17 12:32:34 +01:00
Kerry McLaughlin 6d2a78996b [SVE][CodeGen] Add bfloat16 support to scalable masked gather
Reviewed By: david-arm

Differential Revision: https://reviews.llvm.org/D93307
2020-12-17 11:08:15 +00:00
dfukalov 9ed8e0caab [NFC] Reduce include files dependency and AA header cleanup (part 2).
Continuing work started in https://reviews.llvm.org/D92489:

Removed a bunch of includes from "AliasAnalysis.h" and "LoopPassManager.h".

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D92852
2020-12-17 14:04:48 +03:00
Simon Pilgrim 931e66bd89 [X86] Remove extract_subvector(subv_broadcast_load()) fold.
This was needed in an earlier version of D92645, but isn't now - and I've just noticed that it was potentially flawed depending on the relevant widths of the broadcasted and extracted subvectors.
2020-12-17 11:02:49 +00:00
Krasimir Georgiev e71a4cc207 fix a -Wunused-variable warning in release build 2020-12-17 11:52:00 +01:00
Raphael Isemann b8338983e6 [lldb] Add std::array to the supported template list of the CxxModuleHandler
Identical to the other patches that add STL containers to the supported
templated list.
2020-12-17 11:47:58 +01:00
Barry Revzin 92310454bf Make LLVM build in C++20 mode
Part of the <=> changes in C++20 make certain patterns of writing equality
operators ambiguous with themselves (sorry!).
This patch goes through and adjusts all the comparison operators such that
they should work in both C++17 and C++20 modes. It also makes two other small
C++20-specific changes (adding a constructor to a type that cases to be an
aggregate, and adding casts from u8 literals which no longer have type
const char*).

There were four categories of errors that this review fixes.
Here are canonical examples of them, ordered from most to least common:

// 1) Missing const
namespace missing_const {
    struct A {
    #ifndef FIXED
        bool operator==(A const&);
    #else
        bool operator==(A const&) const;
    #endif
    };

    bool a = A{} == A{}; // error
}

// 2) Type mismatch on CRTP
namespace crtp_mismatch {
    template <typename Derived>
    struct Base {
    #ifndef FIXED
        bool operator==(Derived const&) const;
    #else
        // in one case changed to taking Base const&
        friend bool operator==(Derived const&, Derived const&);
    #endif
    };

    struct D : Base<D> { };

    bool b = D{} == D{}; // error
}

// 3) iterator/const_iterator with only mixed comparison
namespace iter_const_iter {
    template <bool Const>
    struct iterator {
        using const_iterator = iterator<true>;

        iterator();

        template <bool B, std::enable_if_t<(Const && !B), int> = 0>
        iterator(iterator<B> const&);

    #ifndef FIXED
        bool operator==(const_iterator const&) const;
    #else
        friend bool operator==(iterator const&, iterator const&);
    #endif
    };

    bool c = iterator<false>{} == iterator<false>{} // error
          || iterator<false>{} == iterator<true>{}
          || iterator<true>{} == iterator<false>{}
          || iterator<true>{} == iterator<true>{};
}

// 4) Same-type comparison but only have mixed-type operator
namespace ambiguous_choice {
    enum Color { Red };

    struct C {
        C();
        C(Color);
        operator Color() const;
        bool operator==(Color) const;
        friend bool operator==(C, C);
    };

    bool c = C{} == C{}; // error
    bool d = C{} == Red;
}

Differential revision: https://reviews.llvm.org/D78938
2020-12-17 10:44:10 +00:00
Simon Pilgrim cdb692ee0c [X86] Add X86ISD::SUBV_BROADCAST_LOAD and begin removing X86ISD::SUBV_BROADCAST (PR38969)
Subvector broadcasts are only load instructions, yet X86ISD::SUBV_BROADCAST treats them more generally, requiring a lot of fallback tablegen patterns.

This initial patch replaces constant vector lowering inside lowerBuildVectorAsBroadcast with direct X86ISD::SUBV_BROADCAST_LOAD loads which helps us merge a number of equivalent loads/broadcasts.

As well as general plumbing/analysis additions for SUBV_BROADCAST_LOAD, I needed to wrap SelectionDAG::makeEquivalentMemoryOrdering so it can handle result chains from non generic LoadSDNode nodes.

Later patches will continue to replace X86ISD::SUBV_BROADCAST usage.

Differential Revision: https://reviews.llvm.org/D92645
2020-12-17 10:25:25 +00:00
Krasimir Georgiev 352cba2441 [libc] add back math.h #include utils/FPUtil/ManipulationFunctions.h
This partially reverts cee1e7d14f4628d6174b33640d502bff3b54ae45:
  [libc][NFC][Obvious] Remove few unnecessary #include directives in tests.

That commit causes a test failure in our configuration:
[ RUN      ] ILogbTest.SpecialNumbers_ilogb
third_party/llvm/llvm-project/libc/test/src/math/ILogbTest.h:28: FAILURE
      Expected: FP_ILOGBNAN
      Which is: 2147483647
To be equal to: func(__llvm_libc::fputil::FPBits<T>::buildNaN(1))
      Which is: -2147483648
2020-12-17 11:16:08 +01:00
Raphael Isemann 722247c812 [lldb] Unify the two CreateTypedef implementations in TypeSystemClang
To get LLDB one step closer to fulfil the software redundancy requirements of
modern aircrafts, we apparently decided to have two separately maintained
implementations of `CreateTypedef` in TypeSystemClang. Let's pass on the idea of
an LLDB-powered jetliner and deleted one implementation.

On a more serious note: This function got duplicated a long time ago when the
idea of CompilerType with a backing TypeSystemClang subclass happened
(56939cb310). One implementation was supposed to
be called from CompilerType::CreateTypedef and the other has just always been
around to create typedefs. By accident one of the implementations is only used
by the PDB parser while the CompilerType::CreateTypedef backend is used by the
rest of LLDB.

We also had some patches over the year that only fixed one of the two functions
(D18099 for example only fixed up the CompilerType::CreateTypedef
implementation). D51162 and D86140 both fixed the same missing `addDecl` call
for one of the two implementations.

This patch:
* deletes the `CreateTypedefType` function as its only used by the PDB parser
  and the `CreateTypedef` implementation is anyway needed as it's the backend
  implementation of CompilerType.
* replaces the calls in the PDB parser by just calling the CompilerType wrapper.
* moves the documentation to the remaining function.
* moves the check for empty typedef names that was only in the deleted
  implementation to the other (I don't think this fixes anything as I believe
  all callers are already doing the same check).

I'll fix up the usual stuff (not using StringRef, not doing early exit) in a NFC
follow-up.

This patch is not NFC as the PDB parser now calls the function that has the fix
from D18099.

Reviewed By: labath, JDevlieghere

Differential Revision: https://reviews.llvm.org/D93382
2020-12-17 10:49:26 +01:00
sameeran joshi a4e47cd185 [Flang][openmp]Fix crash in OpenMP semantic check( bug 48308)
Fixes the bug reported in https://bugs.llvm.org/show_bug.cgi?id=48308

Reviewed By: kiranchandramohan, clementval

Differential Revision: https://reviews.llvm.org/D92638
2020-12-17 15:17:13 +05:30
mydeveloperday db41c0b357 [clang-format] PR35514 brace-init member initializers in function-try-blocks are not formatted correctly
https://bugs.llvm.org/show_bug.cgi?id=35514

Initializer lists with a try-block are incorrectly formatted.

e.g.

```
Foo(int abc, int def) try : _abc(abc), _def{def}, _ghi{1} {
  callA();
  callB();
} catch (std::exception&) {
}
```

is formatted as:

```
Foo(int abc, int def) try : _abc(abc), _def { def }
, _ghi{1} {
  callA();
  callB();
}
catch (std::exception&) {
}
```

This revision adds support in the parseTryCatch for braced initializers in the initializer list

Reviewed By: curdeius, HazardyKnusperkeks

Differential Revision: https://reviews.llvm.org/D93296
2020-12-17 09:39:37 +00:00
David Spickett 7f8779e4e6 [llvm][AArch64] Actually check expected FPU for CPUs
We were passing this as an argument but never using
it. ARM has always checked this.

Note that the FPU list is shared between ARM and AArch64
so there is no AArch64::getFPUName, just ARM::getFPUName.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D93387
2020-12-17 09:15:51 +00:00
Florian Hahn eba09a2db9
[InstCombine] Preserve !annotation for newly created instructions.
When replacing an instruction with !annotation with a newly created
replacement, add the !annotation metadata to the replacement.

This mostly covers cases where the new instructions are created using
the ::Create helpers. Instructions created by IRBuilder will be handled
by D91444.

Reviewed By: thegameg

Differential Revision: https://reviews.llvm.org/D93399
2020-12-17 09:06:51 +00:00
Andrzej Warzynski 7f19712a6a [clang][nfc] Update comment to match the opening `{` 2020-12-17 09:04:41 +00:00
Michał Górny dbfdb139f7 [lldb] [POSIX-DYLD] Update the cached exe path after attach
Fix the POSIX-DYLD plugin to update the cached executable path after
attaching.  Previously, the path was cached in DYLDRendezvous
constructor and not updated afterwards.  This meant that if LLDB was
attaching to a process (e.g. via connecting to lldb-server), the code
stored the empty path before DidAttach() resolved it.  The fix updates
the cached path in DidAttach().

This fixes a new instance of https://llvm.org/pr17880

Differential Revision: https://reviews.llvm.org/D92264
2020-12-17 09:31:22 +01:00
Michał Górny 8666b9057f [lldb] [POSIX-DYLD] Add libraries from initial rendezvous brkpt hit
Explicitly consider the libraries reported on the initial rendezvous
breakpoint hit added.  This is necessary on FreeBSD since the dynamic
loader issues only a single 'consistent' state rendezvous breakpoint hit
for all the libraries present in DT_NEEDED.  It is also helpful on Linux
where it ensures that ld-linux is considered loaded as well
as the shared system libraries reported afterwards.

Reenable memory maps on FreeBSD since this fixed the issue triggered
by them.

Differential Revision: https://reviews.llvm.org/D92187
2020-12-17 09:31:10 +01:00
Alex Zinenko 96076a2edb [mlir] Support index and memref types in llvm.mlir.cast
This operation is designed to support partial conversion, more specifically the
IR state in which some operations expect or produce built-in types and some
operations produce and expect LLVM dialect types. It is reasonable for it to
support cast between built-in types and any equivalent that could be produced
by the type conversion. (At the same time, we don't want the dialect to depend
on the type conversion as it could lead to a dependency cycle). Introduce
support for casting from index to any integer type and back, and from memref to
bare pointer or memref descriptor type and back.

Contrary to what the TODO in the code stated, there are no particular
precautions necessary to handle the bare pointer conversion for memerfs. This
conversion applies exclusively to statically-shaped memrefs, so we can always
recover the full descriptor contents from the type.

This patch simultaneously tightens the verification for other types to only
accept matching pairs of types, e.g., i64 and !llvm.i64, as opposed to the
previous implementation that only checked if the types were generally allowed
byt not for matching, e.g. i64 could be "casted" to !llvm.bfloat, which is not
the intended semantics.

Move the relevant test under test/Dialect/LLVMIR because it is not specific to
the conversion pass, but rather exercises an op in the dialect. If we decide
this op does not belong to the LLVM dialect, both the dialect and the op should
move together.

Reviewed By: silvas, ezhulenev

Differential Revision: https://reviews.llvm.org/D93405
2020-12-17 09:21:42 +01:00
QingShan Zhang ebdd20f430 Expand the fp_to_int/int_to_fp/fp_round/fp_extend as libcall for fp128
X86 and AArch64 expand it as libcall inside the target. And PowerPC also
want to expand them as libcall for P8. So, propose an implement in the
legalizer to common the logic and remove the code for X86/AArch64 to
avoid the duplicate code.

Reviewed By: Craig Topper

Differential Revision: https://reviews.llvm.org/D91331
2020-12-17 07:59:30 +00:00
Fangrui Song c70f36865e Use basic_string::find(char) instead of basic_string::find(const char *s, size_type pos=0)
Many (StringRef) cannot be detected by clang-tidy performance-faster-string-find.
2020-12-16 23:28:32 -08:00
Wei Mi a906e3eccd [NFC][SampleFDO] Preparation to support multiple sections with the same type
in ExtBinary format.

Currently ExtBinary format doesn't support multiple sections with the same type
in the profile. We add the support in this patch. Previously we use the section
type to identify a section uniquely. Now we introduces a LayoutIndex in the
SecHdrTableEntry and use the LayoutIndex to locate the target section. The
allocations of NameTable and FuncOffsetTable are adjusted accordingly.

Currently it works as a NFC because it won't change anything for current layout.
The test for multiple sections support will be included in another patch where a
new type of profile containing multiple sections with the same type is
introduced.

Differential Revision: https://reviews.llvm.org/D93254
2020-12-16 22:28:45 -08:00
Xiang1 Zhang 39584ae5b5 [Debugify] Support checking Machine IR debug info
Add mir-check-debug pass to check MIR-level debug info.

For IR-level, currently, LLVM have debugify + check-debugify to generate
and check debug IR. Much like the IR-level pass debugify, mir-debugify
inserts sequentially increasing line locations to each MachineInstr in a
Module, But there is no equivalent MIR-level check-debugify pass, So now
we support it at "mir-check-debug".

Reviewed By: djtodoro

Differential Revision: https://reviews.llvm.org/D91595
2020-12-16 22:17:25 -08:00
Kazu Hirata 4ad5b634f6 [GCN] Remove unused function handleNewInstruction (NFC)
The function was added without a user on Dec 22, 2016 in commit
7e274e02ae.  It seems to be unused since
then.
2020-12-16 21:57:48 -08:00
Kazu Hirata 5501b92957 [IR, CodeGen] Use llvm::is_contained (NFC) 2020-12-16 21:30:44 -08:00
Mircea Trofin ed1e565aaf [NFC] factor update test function test builder as a class
This allows us to have shared logic over multiple test runs, e.g. do we
have unused prefixes, or which function bodies have conflicting outputs
for a prefix appearing in different RUN lines.

This patch is just wrapping existing functionality, and replacing its uses.
A subsequent patch would then fold the current functionality into the newly
introduced class.

Differential Revision: https://reviews.llvm.org/D93413
2020-12-16 21:12:06 -08:00
Craig Topper 541e476fc0 [RISCV] Infer mask type from data type for vector vle and vse intrinsics.
The mask type should have the same number of elements as the data
type.

Similar to D93409 which did this for arithmetic intrinsics.
2020-12-16 20:56:14 -08:00
River Riddle fce9dd6b25 [mlir][NFC] Remove StandardTypes.h now that all usages point to BuiltinTypes.h
Differential Revision: https://reviews.llvm.org/D93430
2020-12-16 20:41:42 -08:00
Craig Topper 0d7dd026c8 [RISCV] Infer mask type for vector intrinsics from the data type
We can use LLVMScalarOrSameVectorWidth<0, llvm_i1_ty> to infer the mask type from the anyvector_ty. This will save us from needing to pass it to getDeclaration when creating these intrinsics from clang.

No tests updates are needed because our declarations are exploiting a behavior in the IR parser where the declaration of an intrinsic doesn't need to mention all the types as long as there isn't a name conflict in the file.

Reviewed By: khchen

Differential Revision: https://reviews.llvm.org/D93409
2020-12-16 20:18:30 -08:00
Xiang1 Zhang 1e42ad9d62 Revert "[Debugify] Support checking Machine IR debug info"
This reverts commit 50aaa8c274.
2020-12-16 20:12:33 -08:00
Hsiangkai Wang a5e4a513b0 [RISCV] Define vector widening mul intrinsics.
Define vector widening mul intrinsics and lower them to V instructions.

We work with @rogfer01 from BSC to come out this patch.

Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Hsiangkai Wang <kai.wang@sifive.com>

Differential Revision: https://reviews.llvm.org/D93381
2020-12-17 11:50:33 +08:00
Hsiangkai Wang dd5281e7cc [RISCV] Define vector mul/div/rem intrinsics.
Define vector mul/div/rem intrinsics and lower them to V instructions.

We work with @rogfer01 from BSC to come out this patch.

Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Hsiangkai Wang <kai.wang@sifive.com>

Differential Revision: https://reviews.llvm.org/D93380
2020-12-17 11:50:17 +08:00
Hsiangkai Wang f03609b5c7 [RISCV] V does not imply F.
If users want to use vector floating point instructions, they need to
specify 'F' extension additionally.

Differential Revision: https://reviews.llvm.org/D93282
2020-12-17 10:57:36 +08:00
Matt Arsenault f333736757 AMDGPU: Remove SGPRSpillVGPRDefinedSet hack
These VGPRs should be reserved and therefore do not need "correct"
liveness. They should not have undef uses, which can still cause
issues.
2020-12-16 21:33:35 -05:00
Zakk Chen c1d6d461aa [RISCV] Define vle/vse intrinsics.
Define vle/vse intrinsics and lower to V instructions.

We work with @rogfer01 from BSC to come out this patch.

Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Zakk Chen <zakk.chen@sifive.com>

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D93359
2020-12-16 18:08:15 -08:00
Xiang1 Zhang 50aaa8c274 [Debugify] Support checking Machine IR debug info
Add mir-check-debug pass to check MIR-level debug info.

For IR-level, currently, LLVM have debugify + check-debugify to generate
and check debug IR. Much like the IR-level pass debugify, mir-debugify
inserts sequentially increasing line locations to each MachineInstr in a
Module, But there is no equivalent MIR-level check-debugify pass, So now
we support it at "mir-check-debug".

Reviewed By: djtodoro

Differential Revision: https://reviews.llvm.org/D91595
2020-12-16 18:04:05 -08:00
Johannes Doerfert 2e6e4e6aee [OpenMP] Add initial support for `omp [begin/end] assumes`
The `assumes` directive is an OpenMP 5.1 feature that allows the user to
provide assumptions to the optimizer. Assumptions can refer to
directives (`absent` and `contains` clauses), expressions (`holds`
clause), or generic properties (`no_openmp_routines`, `ext_ABCD`, ...).

The `assumes` spelling is used for assumptions in the global scope while
`assume` is used for executable contexts with an associated structured
block.

This patch only implements the global spellings. While clauses with
arguments are "accepted" by the parser, they will simply be ignored for
now. The implementation lowers the assumptions directly to the
`AssumptionAttr`.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D91980
2020-12-16 20:02:49 -06:00
Nico Weber f48dae3108 [gn build] (manually) port ddffcdf0a6 2020-12-16 20:49:56 -05:00
Arthur Eubanks 4c8c636871 [test] Cleanup some CGSCCPassManager tests
Don't iterate over SCC as we potentially modify it.
Verify module (and fix some broken ones).
Only run pass once and make sure that it's actually run.
Rename tests to just end in a number since I'm planning on adding a
bunch more which won't have good individual names. Instead, add comments
on the transformations that each test does.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D93427
2020-12-16 16:25:55 -08:00
Nathan James ddffcdf0a6
[clang-tidy] Add a diagnostic callback to parseConfiguration
Currently errors detected when parsing the YAML for .clang-tidy files are always printed to errs.
For clang-tidy binary workflows this usually isn't an issue, but using clang-tidy as a library for integrations may want to handle displaying those errors in their own specific way.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D92920
2020-12-17 00:24:58 +00:00
Tres Popp b17a181563 [mlir] Modify linalg loops test to have nested regions
Differential Revision: https://reviews.llvm.org/D93418
2020-12-17 01:19:46 +01:00
LLVM GN Syncbot 672cdc84d2 [gn build] Port ac068e014b 2020-12-17 00:07:28 +00:00
Atmn 907886cc5b [OpenMP][Libomptarget][NFC] Use CMake Variables
This patchs adds CMake variables to add subdirectories and include
directories for libomptarget and explicitly gives the location of source
files.

Differential Revision: https://reviews.llvm.org/D93290
2020-12-16 19:05:15 -05:00
Hongtao Yu ac068e014b [CSSPGO] Consume pseudo-probe-based AutoFDO profile
This change enables pseudo-probe-based sample counts to be consumed by the sample profile loader under the regular `-fprofile-sample-use` switch with minimal adjustments to the existing sample file formats. After the counts are imported, a probe helper, aka, a `PseudoProbeManager` object, is automatically launched to verify the CFG checksum of every function in the current compilation against the corresponding checksum from the profile. Mismatched checksums will cause a function profile to be slipped. A `SampleProfileProber` pass is scheduled before any of the `SampleProfileLoader` instances so that the CFG checksums as well as probe mappings are available during the profile loading time. The `PseudoProbeManager` object is set up right after the profile reading is done. In the future a CFG-based fuzzy matching could be done in `PseudoProbeManager`.

Samples will be applied only to pseudo probe instructions as well as probed callsites once the checksum verification goes through. Those instructions are processed in the same way that regular instructions would be processed in the line-number-based scenario. In other words, a function is processed in a regular way as if it was reduced to just containing pseudo probes (block probes and callsites).

**Adjustment to profile format **

A CFG checksum field is being added to the existing AutoFDO profile formats. So far only the text format and the extended binary format are supported. For the text format, a new line like
```
!CFGChecksum: 12345
```
is added to the end of the body sample lines. For the extended binary profile format, we introduce a metadata section to store the checksum map from function names to their CFG checksums.

Differential Revision: https://reviews.llvm.org/D92347
2020-12-16 15:57:18 -08:00
Guozhi Wei 687e80be7f [MBP] Add whole chain to BlockFilterSet instead of individual BB
Currently we add individual BB to BlockFilterSet if its frequency satisfies

  LoopFreq / Freq <= LoopToColdBlockRatio

LoopFreq is edge frequency from outside to loop header.
LoopToColdBlockRatio is a command line parameter.

It doesn't make sense since we always layout whole chain, not individual BBs.

It may also cause a tricky problem. Sometimes it is possible that the LoopFreq
of an inner loop is smaller than LoopFreq of outer loop. So a BB can be in
BlockFilterSet of inner loop, but not in BlockFilterSet of outer loop,
like .cold in the test case. So it is added to the chain of inner loop. When
work on the outer loop, .cold is not added to BlockFilterSet, so the edge to
successor .problem is not counted in UnscheduledPredecessors of .problem chain.
But other blocks in the inner loop are added BlockFilterSet, so the whole inner
loop chain can be layout, and markChainSuccessors is called to decrease
UnscheduledPredecessors of following chains. markChainSuccessors calls
markBlockSuccessors for every BB, even it is not in BlockFilterSet, like .cold,
so .problem chain's UnscheduledPredecessors is decreased, but this edge was not
counted on in fillWorkLists, so .problem chain's UnscheduledPredecessors
becomes 0 when it still has an unscheduled predecessor .pred! And it causes
problems in following various successor BB selection algorithms.

Differential Revision: https://reviews.llvm.org/D89088
2020-12-16 15:45:47 -08:00