Before this change, the *InstPrinter.cpp files of each target where some
of the slowest objects to compile in all of LLVM. See this snippet produced by
ClangBuildAnalyzer:
https://reviews.llvm.org/P8171$96
Search for "InstPrinter", and see that it shows up in a few places.
Tablegen was emitting a large switch containing a sequence of operand checks,
each of which created many conditions and many BBs. Register allocation and
jump threading both did not scale well with such a large repetitive sequence of
basic blocks.
So, this change essentially turns those control flow structures into
data. The previous structure looked like:
switch (Opc) {
case TGT::ADD:
// check alias 1
if (MI->getOperandCount() == N && // check num opnds
MI->getOperand(0).isReg() && // check opnd 0
...
MI->getOperand(1).isImm() && // check opnd 1
AsmString = "foo";
break;
}
// check alias 2
if (...)
...
return false;
The new structure looks like:
OpToPatterns: Sorted table of opcodes mapping to pattern indices.
\->
Patterns: List of patterns. Previous table points to subrange of
patterns to match.
\->
Conds: The if conditions above encoded as a kind and 32-bit value.
See MCInstPrinter.cpp for the details of how the new data structures are
interpreted.
Here are some before and after metrics.
Time to compile AArch64InstPrinter.cpp:
0m29.062s vs. 0m2.203s
size of the obj:
3.9M vs. 676K
size of clang.exe:
97M vs. 96M
I have not benchmarked disassembly performance, but typically
disassemblers are bottlenecked on IO and string processing, not alias
matching, so I'm not sure it's interesting enough to be worth doing.
Reviewers: RKSimon, andreadb, xbolva00, craig.topper
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D70650
This reverts commit 3f76260dc0674cc0acb25f550a0f0c594cf537ea.
Breaks at least these tests on Windows:
Clang :: Driver/clang-offload-bundler.c
Clang :: Driver/clang-offload-wrapper.c
For lldb and dsymutil, the command guide is essentially a copy of its
help output generated by libOption. Making sure the two stay in sync is
tedious and error prone. Given that we already generate the help from a
tablegen file, we might as well generate the RST as well.
This adds a tablegen backend for generating Sphinx/RST command guides
from the tablegen file.
Differential revision: https://reviews.llvm.org/D70610
* Implements scalable size queries for MVTs, split out from D53137.
* Contains a fix for FindMemType to avoid using scalable vector type
to contain non-scalable types.
* Explicit casts for several places where implicit integer sign
changes or promotion from 32 to 64 bits caused problems.
* CodeGenDAGPatterns will treat scalable and non-scalable vector types
as different.
Reviewers: greened, cameron.mcinally, sdesmalen, rovka
Reviewed By: rovka
Differential Revision: https://reviews.llvm.org/D66871
AMDGPU has some atomic instructions that do not return the previous
result, and can only be selected if there are no uses. The source
pattern will only match if the use is empty, so it should be safe to
discard the result.
Summary:
To drive the automaton we used a uint64_t as an action type. This
contained the transition's resource requirements as a conjunction:
(a OR b) AND (b OR c)
We encoded this conjunction as a sequence of four 16-bit bitmasks.
This limited the number of addressable functional units to 16, which
is quite low and has bitten many people in the past.
Instead, the DFAEmitter now generates a lookup table from InstrItinerary
class (index of the ItinData inside the ProcItineraries) to an internal
action index which is essentially a dense embedding of the conjunctive
form. Because we never materialize the conjunctive form, we no longer
have the 16 FU restriction.
In this patch we limit to 64 functional units due to using a uint64_t
bitmask in the DFAEmitter. Now that we've decoupled these representations
we can increase this in future.
Reviewers: ThomasRaoux, kparzysz, majnemer
Reviewed By: ThomasRaoux
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69110
Summary:
Found by PVS Studio
Not familiar with this code; no testcase.
Reviewers: craig.topper, RKSimon
Reviewed By: RKSimon
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69741
If there is a dag node with a variable number of operands that has at
least N operands (for some non-negative N), and multiple patterns with
that node with different number of operands, we would drop the number of
operands check in patterns with N operands, presumably because it's
guaranteed in such case that none of the per-operand checks will access
the operand list out-of-bounds.
Except semantically the check is about having exactly N operands, not at
least N operands, and a backend might rely on it to disambiguate
different patterns.
In this patch we change the condition on emitting the number of operands
check from "the instruction is not guaranteed to have at least as many
operands as are checked by the pattern being matched" to "the
instruction is not guaranteed to have a specific number of operands".
We're relying (still) on the rest of the CodeGenPatterns mechanics to
validate that the pattern itself doesn't try to access more operands
than there is in the instruction in cases when the instruction does have
fixed number of operands, and on the machine verifier to validate at
runtime that particular MIs like that satisfy the constraint as well.
Reviewers: dsanders, qcolombet
Reviewed By: qcolombet
Subscribers: arsenm, rovka, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69653
D68992 / rL375086 refactored the packetizer and removed a bunch of logic. Unfortunately it creates an Automaton object whenever a DFAPacketizer is required. These objects have no longevity, and in particular on a debug build the population of the Automaton's transition map from the underlying table is very slow (because it is called ~10 times per MachineFunction, in the testcase I'm looking at).
This patch changes Automaton to wrap its underlying constant data in std::shared_ptr, which allows trivial copy construction. The DFAPacketizer creation function now creates a static archetypical Automaton and copies that whenever a new DFAPacketizer is required.
This takes a testcase down from ~20s to ~0.5s in debug mode.
llvm-svn: 375240
Summary:
This is a NFC change that removes the NFA->DFA construction and emission logic from DFAPacketizerEmitter and instead uses the generic DFAEmitter logic. This allows DFAPacketizer to use the Automaton class from Support and remove a bunch of logic there too.
After this patch, DFAPacketizer is mostly logic for grepping Itineraries and collecting functional units, with no state machine logic. This will allow us to modernize by removing the 16-functional-unit limit and supporting non-itinerary functional units. This is all for followup patches.
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68992
llvm-svn: 375086
Summary:
Each generated helper can be configured to generate an option that disables
rules in that helper. This can be used to bisect rulesets.
The disable bits are stored in a SparseVector as this is very cheap for the
common case where nothing is disabled. It gets more expensive the more rules
are disabled but you're generally doing that for debug purposes where
performance is less of a concern.
Depends on D68426
Reviewers: volkan, bogner
Reviewed By: volkan
Subscribers: hiraditya, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68438
llvm-svn: 375067
Summary:
This is just moving the existing C++ code around and will be NFC w.r.t
AArch64. Renamed 'CombineBr' to something more descriptive
('ElideByByInvertingCond') at the same time.
The remaining combines in AArch64PreLegalizeCombiner require features that
aren't implemented at this point and will be hoisted as they are added.
Depends on D68424
Reviewers: bogner, volkan
Subscribers: kristof.beyls, hiraditya, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68426
llvm-svn: 375057
Assume that, ModelA has scheduling resource for InstA and ModelB has scheduling resource for InstB. This is what the llvm::MCSchedClassDesc looks like:
llvm::MCSchedClassDesc ModelASchedClasses[] = {
...
InstA, 0, ...
InstB, -1,...
};
llvm::MCSchedClassDesc ModelBSchedClasses[] = {
...
InstA, -1,...
InstB, 0,...
};
The -1 means invalid num of macro ops, while it is valid if it is >=0. This is what we look like now:
llvm::MCSchedClassDesc ModelASchedClasses[] = {
...
InstA, 0, ...
InstB, 0,...
};
llvm::MCSchedClassDesc ModelBSchedClasses[] = {
...
InstA, 0,...
InstB, 0,...
};
And compiler hit the assertion here because the SCDesc is valid now for both InstA and InstB.
Differential Revision: https://reviews.llvm.org/D67950
llvm-svn: 374524
When an instruction has an encoding definition for only a subset of
the available HwModes, ensure we just avoid generating an encoding
rather than crash.
llvm-svn: 374150
Summary:
While working with DagInit's, it's often the case that you expect the
operator to be a reference to a def. This patch adds a wrapper for this
common case to reduce the amount of boilerplate callers need to duplicate
repeatedly.
getOperatorAsDef() returns the record if the DagInit has an operator that is
a DefInit. Otherwise, it prints a fatal error.
There's only a few pre-existing examples in LLVM at the moment and I've
left a few instances of the code this simplifies as they had more specific
error messages than the generic one this produces. I'm going to be using
this a fair bit in my subsequent patches.
Reviewers: bogner, volkan, nhaehnle
Reviewed By: nhaehnle
Subscribers: nhaehnle, hiraditya, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, lenary, s.egerton, pzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68424
llvm-svn: 374101
Allows targets to introduce regbankselectable
pseudo-instructions. Currently the closet feature to this is an
intrinsic. However this requires creating a public intrinsic
declaration. This litters the public intrinsic namespace with
operations we don't necessarily want to expose to IR producers, and
would rather leave as private to the backend.
Use a new instruction bit. A previous attempt tried to keep using enum
value ranges, but it turned into a mess.
llvm-svn: 373937
Summary:
This patch introduces -gen-automata, a backend for generating deterministic finite-state automata.
DFAs are already generated by the -gen-dfa-packetizer backend. This backend is more generic and will
hopefully be used to implement the DFA generation (and determinization) for the packetizer in the
future.
This backend allows not only generation of a DFA from an NFA (nondeterministic finite-state
automaton), it also emits sidetables that allow a path through the DFA under a sequence of inputs to
be analyzed, and the equivalent set of all possible NFA transitions extracted.
This allows a user to not just answer "can my problem be solved?" but also "what is the
solution?". Clearly this analysis is more expensive than just playing a DFA forwards so is
opt-in. The DFAPacketizer has this behaviour already but this is a more compact and generic
representation.
Examples are bundled in unittests/TableGen/Automata.td. Some are trivial, but the BinPacking example
is a stripped-down version of the original target problem I set out to solve, where we pack values
(actually immediates) into bins (an immediate pool in a VLIW bundle) subject to a set of esoteric
constraints.
Reviewers: t.p.northover
Subscribers: mgorny, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67968
llvm-svn: 373718
Summary:
This will handle expansion of C++ fragments in the declarative combiner
including custom predicates, and escapes into C++ to aid the migration
effort.
Fixed the -DLLVM_LINK_LLVM_DYLIB=ON using DISABLE_LLVM_LINK_LLVM_DYLIB when
creating the library. Apparently it automatically links to libLLVM.dylib
and we don't want that from tablegen.
Reviewers: bogner, volkan
Subscribers: mgorny, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68288
> llvm-svn: 373551
llvm-svn: 373651
Summary:
This will handle expansion of C++ fragments in the declarative combiner
including custom predicates, and escapes into C++ to aid the migration
effort.
Reviewers: bogner, volkan
Subscribers: mgorny, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68288
llvm-svn: 373551
Summary:
This is the first of a series of patches extracted from a much bigger WIP
patch. It merely establishes the tblgen pass and the way empty combiner
helpers are declared and integrated into a combiner info.
The tablegen pass takes a -combiners option to select the combiner helper
that will be generated. This can be given multiple values to generate
multiple combiner helpers at once. Doing so helps to minimize parsing
overhead.
The reason for creating a GlobalISel subdirectory in utils/TableGen is that
there will be quite a lot of non-pass files (~15) by the time the patch
series is done.
Reviewers: volkan
Subscribers: mgorny, hiraditya, simoncook, Petar.Avramovic, s.egerton, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68286
llvm-svn: 373527
Summary:
This allows intrinsics such as the following to be defined:
- declare <n x 4 x i32> @llvm.something.nxv4f32(<n x 4 x i32>, <n x 4 x i1>, <n x 4 x float>)
...where <n x 4 x i32> is derived from <n x 4 x float>, but
the element needs bitcasting to int.
Reviewers: c-rhodes, sdesmalen, rovka
Reviewed By: c-rhodes
Subscribers: tschuett, hiraditya, jdoerfert, llvm-commits, cfe-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68021
llvm-svn: 373437
Previously the match was ambiguous and VMAXPS/PD and VMAXCPS/PD
were mapped to the same VEX instruction. But we should keep
the commutableness when change the opcode.
llvm-svn: 373303
