Commit Graph

219 Commits

Author SHA1 Message Date
Bevin Hansson c3f36acc92 [MC] Widen the functional unit type from 32 to 64 bits.
Summary:
The type used to represent functional units in MC is
'unsigned', which is 32 bits wide. This is currently
not a problem in any upstream target as no one seems
to have hit the limit on this yet, but in our
downstream one, we need to define more than 32
functional units.

Increasing the size does not seem to cause a huge
size increase in the binary (an llc debug build went
from 1366497672 to 1366523984, a difference of 26k),
so perhaps it would be acceptable to have this patch
applied upstream as well.

Subscribers: hiraditya, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71210
2020-02-24 09:37:00 +01:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
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.
2020-01-28 23:25:25 +01:00
QingShan Zhang bb8d540010 [TableGen] Fix a bug that MCSchedClassDesc is interfered between different SchedModel
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
2019-10-11 08:36:54 +00:00
James Molloy 88a5fbfcea [TableGen] Support encoding per-HwMode
Much like ValueTypeByHwMode/RegInfoByHwMode, this patch allows targets
to modify an instruction's encoding based on HwMode. When the
EncodingInfos field is non-empty the Inst and Size fields of the Instruction
are ignored and taken from EncodingInfos instead.

As part of this promote getHwMode() from TargetSubtargetInfo to MCSubtargetInfo.

This is NFC for all existing targets - new code is generated only if targets
use EncodingByHwMode.

llvm-svn: 372320
2019-09-19 13:39:54 +00:00
Bjorn Pettersson 6bd3a9eaa6 [TableGen] Correct comments for end of namespace. NFC
Summary:
Update end-of-namespace comments generated by
tablegen emitters to fulfill the rules setup by
clang-tidy's llvm-namespace-comment checker.

Fixed a few end-of-namespace comments in the
tablegen source code as well.

Reviewers: craig.topper

Reviewed By: craig.topper

Subscribers: craig.topper, stoklund, dschuff, sbc100, jgravelle-google, aheejin, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66396

llvm-svn: 369865
2019-08-25 10:47:30 +00:00
Thomas Lively 3f34e1b883 [WebAssembly] Merge used feature sets, update atomics linkage policy
Summary:
It does not currently make sense to use WebAssembly features in some functions
but not others, so this CL adds an IR pass that takes the union of all used
feature sets and applies it to each function in the module. This allows us to
prevent atomics from being lowered away if some function has opted in to using
them. When atomics is not enabled anywhere, we detect whether there exists any
atomic operations or thread local storage that would be stripped and disallow
linking with objects that contain atomics if and only if atomics or tls are
stripped. When atomics is enabled, mark it as used but do not require it of
other objects in the link. These changes allow libraries that do not use atomics
to be built once and linked into both single-threaded and multithreaded
binaries.

Reviewers: aheejin, sbc100, dschuff

Subscribers: jgravelle-google, hiraditya, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59625

llvm-svn: 357226
2019-03-29 00:14:01 +00:00
Craig Topper 2982b846e9 [Subtarget] Merge ProcSched and ProcDesc arrays in MCSubtargetInfo into a single array.
These arrays are both keyed by CPU name and go into the same tablegenerated file. Merge them so we only need to store keys once.

This also removes a weird space saving quirk where we used the ProcDesc.size() to create to build an ArrayRef for ProcSched.

Differential Revision: https://reviews.llvm.org/D58939

llvm-svn: 355431
2019-03-05 18:54:38 +00:00
Craig Topper ca26808da9 [Subtarget] Create a separate SubtargetSubtargetKV struct for ProcDesc to remove fields from the stack tables that aren't needed for CPUs
The description for CPUs was just the CPU name wrapped with "Select the " and " processor". We can just do that directly in the help printer instead of making a separate version in the binary for each CPU.

Also remove the Value field that isn't needed and was always 0.

Differential Revision: https://reviews.llvm.org/D58938

llvm-svn: 355429
2019-03-05 18:54:34 +00:00
Craig Topper 2729a91825 [Subtarget] Follow up to r355167, add another set of curly braces to FeatureBitArray initialization to satisfy older versions of clang.
Apparently older versions of clang like 3.6 require an extra set of curly braces around std::array initializations. I'm told the C++ language was changed regarding this by CWG 1270.

llvm-svn: 355327
2019-03-04 19:23:37 +00:00
Craig Topper 4f61308af2 [Subtarget] Remove static global constructor call from the tablegened subtarget feature tables
Subtarget features are stored in a std::bitset that has been subclassed. There is a special constructor to allow the tablegen files to provide a list of bits to initialize the std::bitset to. This constructor isn't constexpr and std::bitset doesn't support many constexpr operations either. This results in a static global constructor being used to initialize the feature bitsets in these files at startup.

To fix this I've introduced a new FeatureBitArray class that holds three 64-bit values representing the initial bit values and taught tablegen to emit hex constants for them based on the feature enum values. This makes the tablegen files less readable than they were before. I can add the list of features back as a comment if we think that's important.

I've added a method to convert from this class into the std::bitset subclass we had before. I considered making the new FeatureBitArray class just implement the std::bitset interface we need instead, but thought I'd see how others felts about that first.

I've simplified the interfaces to SetImpliedBits and ClearImpliedBits a little minimize the number of times we need to convert to the bitset.

This removes about 27K from my local release+asserts build of llc.

Differential Revision: https://reviews.llvm.org/D58520

llvm-svn: 355167
2019-03-01 02:19:26 +00:00
Craig Topper 4cf59aaf08 [MC] Make SubtargetFeatureKV only store one FeatureBitset and use an 'unsigned' to hold the value.
This class is used for two difference tablegen generated tables. For one of the tables the Value FeatureBitset only has one bit set. For the other usage the Implies field was unused.

This patch changes the Value field to just be an unsigned. For the usage that put a real vector in bitset, we now use the previously unused Implies field and leave the Value field unused instead.

This is good for a 16K reduction in the size of llc on my local build with all targets enabled.

llvm-svn: 354243
2019-02-18 06:46:17 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Andrea Di Biagio 373a4ccf6c [llvm-mca][MC] Add the ability to declare which processor resources model load/store queues (PR36666).
This patch adds the ability to specify via tablegen which processor resources
are load/store queue resources.

A new tablegen class named MemoryQueue can be optionally used to mark resources
that model load/store queues.  Information about the load/store queue is
collected at 'CodeGenSchedule' stage, and analyzed by the 'SubtargetEmitter' to
initialize two new fields in struct MCExtraProcessorInfo named `LoadQueueID` and
`StoreQueueID`.  Those two fields are identifiers for buffered resources used to
describe the load queue and the store queue.
Field `BufferSize` is interpreted as the number of entries in the queue, while
the number of units is a throughput indicator (i.e. number of available pickers
for loads/stores).

At construction time, LSUnit in llvm-mca checks for the presence of extra
processor information (i.e. MCExtraProcessorInfo) in the scheduling model.  If
that information is available, and fields LoadQueueID and StoreQueueID are set
to a value different than zero (i.e. the invalid processor resource index), then
LSUnit initializes its LoadQueue/StoreQueue based on the BufferSize value
declared by the two processor resources.

With this patch, we more accurately track dynamic dispatch stalls caused by the
lack of LS tokens (i.e. load/store queue full). This is also shown by the
differences in two BdVer2 tests. Stalls that were previously classified as
generic SCHEDULER FULL stalls, are not correctly classified either as "load
queue full" or "store queue full".

About the differences in the -scheduler-stats view: those differences are
expected, because entries in the load/store queue are not released at
instruction issue stage. Instead, those are released at instruction executed
stage.  This is the main reason why for the modified tests, the load/store
queues gets full before PdEx is full.

Differential Revision: https://reviews.llvm.org/D54957

llvm-svn: 347857
2018-11-29 12:15:56 +00:00
Evandro Menezes 079bf4b7b4 [TableGen] Emit more variant transitions
`llvm-mca` relies on the predicates to be based on `MCSchedPredicate` in order
to resolve the scheduling for variant instructions.  Otherwise, it aborts
the building of the instruction model early.

However, the scheduling model emitter in `TableGen` gives up too soon, unless
all processors use only such predicates.

In order to allow more processors to be used with `llvm-mca`, this patch
emits scheduling transitions if any processor uses these predicates.  The
transition emitted for the processors using legacy predicates is the one
specified with `NoSchedPred`, which is based on `MCSchedPredicate`.

Preferably, `llvm-mca` should instead assume a reasonable default when a
variant transition is not based on `MCSchedPredicate` for a given processor.
This issue should be revisited in the future.

Differential revision: https://reviews.llvm.org/D54648

llvm-svn: 347504
2018-11-23 21:17:33 +00:00
Clement Courbet 41c8af3924 [MCSched] Bind PFM Counters to the CPUs instead of the SchedModel.
Summary:
The pfm counters are now in the ExegesisTarget rather than the
MCSchedModel (PR39165).

This also compresses the pfm counter tables (PR37068).

Reviewers: RKSimon, gchatelet

Subscribers: mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D52932

llvm-svn: 345243
2018-10-25 07:44:01 +00:00
Andrea Di Biagio 6eebbe0a97 [tblgen][llvm-mca] Add the ability to describe move elimination candidates via tablegen.
This patch adds the ability to identify instructions that are "move elimination
candidates". It also allows scheduling models to describe processor register
files that allow move elimination.

A move elimination candidate is an instruction that can be eliminated at
register renaming stage.
Each subtarget can specify which instructions are move elimination candidates
with the help of tablegen class "IsOptimizableRegisterMove" (see
llvm/Target/TargetInstrPredicate.td).

For example, on X86, BtVer2 allows both GPR and MMX/SSE moves to be eliminated.
The definition of 'IsOptimizableRegisterMove' for BtVer2 looks like this:

```
def : IsOptimizableRegisterMove<[
  InstructionEquivalenceClass<[
    // GPR variants.
    MOV32rr, MOV64rr,

    // MMX variants.
    MMX_MOVQ64rr,

    // SSE variants.
    MOVAPSrr, MOVUPSrr,
    MOVAPDrr, MOVUPDrr,
    MOVDQArr, MOVDQUrr,

    // AVX variants.
    VMOVAPSrr, VMOVUPSrr,
    VMOVAPDrr, VMOVUPDrr,
    VMOVDQArr, VMOVDQUrr
  ], CheckNot<CheckSameRegOperand<0, 1>> >
]>;
```

Definitions of IsOptimizableRegisterMove from processor models of a same
Target are processed by the SubtargetEmitter to auto-generate a target-specific
override for each of the following predicate methods:

```
bool TargetSubtargetInfo::isOptimizableRegisterMove(const MachineInstr *MI)
const;
bool MCInstrAnalysis::isOptimizableRegisterMove(const MCInst &MI, unsigned
CPUID) const;
```

By default, those methods return false (i.e. conservatively assume that there
are no move elimination candidates).

Tablegen class RegisterFile has been extended with the following information:
 - The set of register classes that allow move elimination.
 - Maxium number of moves that can be eliminated every cycle.
 - Whether move elimination is restricted to moves from registers that are
   known to be zero.

This patch is structured in three part:

A first part (which is mostly boilerplate) adds the new
'isOptimizableRegisterMove' target hooks, and extends existing register file
descriptors in MC by introducing new fields to describe properties related to
move elimination.

A second part, uses the new tablegen constructs to describe move elimination in
the BtVer2 scheduling model.

A third part, teaches llm-mca how to query the new 'isOptimizableRegisterMove'
hook to mark instructions that are candidates for move elimination. It also
teaches class RegisterFile how to describe constraints on move elimination at
PRF granularity.

llvm-mca tests for btver2 show differences before/after this patch.

Differential Revision: https://reviews.llvm.org/D53134

llvm-svn: 344334
2018-10-12 11:23:04 +00:00
Fangrui Song 0cac726a00 llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...)
Summary: The convenience wrapper in STLExtras is available since rL342102.

Reviewers: dblaikie, javed.absar, JDevlieghere, andreadb

Subscribers: MatzeB, sanjoy, arsenm, dschuff, mehdi_amini, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, eraman, aheejin, kbarton, JDevlieghere, javed.absar, gbedwell, jrtc27, mgrang, atanasyan, steven_wu, george.burgess.iv, dexonsmith, kristina, jsji, llvm-commits

Differential Revision: https://reviews.llvm.org/D52573

llvm-svn: 343163
2018-09-27 02:13:45 +00:00
Clement Courbet 596c56ff9c [llvm-exegesis] Add support for measuring NumMicroOps.
Summary:
Example output for vzeroall:

---
mode:            uops
key:
  instructions:
    - 'VZEROALL'
  config:          ''
  register_initial_values:
cpu_name:        haswell
llvm_triple:     x86_64-unknown-linux-gnu
num_repetitions: 10000
measurements:
  - { debug_string: HWPort0, value: 0.0006, per_snippet_value: 0.0006,
      key: '3' }
  - { debug_string: HWPort1, value: 0.0011, per_snippet_value: 0.0011,
      key: '4' }
  - { debug_string: HWPort2, value: 0.0004, per_snippet_value: 0.0004,
      key: '5' }
  - { debug_string: HWPort3, value: 0.0018, per_snippet_value: 0.0018,
      key: '6' }
  - { debug_string: HWPort4, value: 0.0002, per_snippet_value: 0.0002,
      key: '7' }
  - { debug_string: HWPort5, value: 1.0019, per_snippet_value: 1.0019,
      key: '8' }
  - { debug_string: HWPort6, value: 1.0033, per_snippet_value: 1.0033,
      key: '9' }
  - { debug_string: HWPort7, value: 0.0001, per_snippet_value: 0.0001,
      key: '10' }
  - { debug_string: NumMicroOps, value: 20.0069, per_snippet_value: 20.0069,
      key: NumMicroOps }
error:           ''
info:            ''
assembled_snippet: C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C3
...

Reviewers: gchatelet

Subscribers: tschuett, RKSimon, andreadb, llvm-commits

Differential Revision: https://reviews.llvm.org/D52539

llvm-svn: 343094
2018-09-26 11:22:56 +00:00
Andrea Di Biagio 8b6c314be1 [TableGen][SubtargetEmitter] Add the ability for processor models to describe dependency breaking instructions.
This patch adds the ability for processor models to describe dependency breaking
instructions.

Different processors may specify a different set of dependency-breaking
instructions.
That means, we cannot assume that all processors of the same target would use
the same rules to classify dependency breaking instructions.

The main goal of this patch is to provide the means to describe dependency
breaking instructions directly via tablegen, and have the following
TargetSubtargetInfo hooks redefined in overrides by tabegen'd
XXXGenSubtargetInfo classes (here, XXX is a Target name).

```
virtual bool isZeroIdiom(const MachineInstr *MI, APInt &Mask) const {
  return false;
}

virtual bool isDependencyBreaking(const MachineInstr *MI, APInt &Mask) const {
  return isZeroIdiom(MI);
}
```

An instruction MI is a dependency-breaking instruction if a call to method
isDependencyBreaking(MI) on the STI (TargetSubtargetInfo object) evaluates to
true. Similarly, an instruction MI is a special case of zero-idiom dependency
breaking instruction if a call to STI.isZeroIdiom(MI) returns true.
The extra APInt is used for those targets that may want to select which machine
operands have their dependency broken (see comments in code).
Note that by default, subtargets don't know about the existence of
dependency-breaking. In the absence of external information, those method calls
would always return false.

A new tablegen class named STIPredicate has been added by this patch to let
processor models classify instructions that have properties in common. The idea
is that, a MCInstrPredicate definition can be used to "generate" an instruction
equivalence class, with the idea that instructions of a same class all have a
property in common.

STIPredicate definitions are essentially a collection of instruction equivalence
classes.
Also, different processor models can specify a different variant of the same
STIPredicate with different rules (i.e. predicates) to classify instructions.
Tablegen backends (in this particular case, the SubtargetEmitter) will be able
to process STIPredicate definitions, and automatically generate functions in
XXXGenSubtargetInfo.

This patch introduces two special kind of STIPredicate classes named
IsZeroIdiomFunction and IsDepBreakingFunction in tablegen. It also adds a
definition for those in the BtVer2 scheduling model only.

This patch supersedes the one committed at r338372 (phabricator review: D49310).

The main advantages are:
 - We can describe subtarget predicates via tablegen using STIPredicates.
 - We can describe zero-idioms / dep-breaking instructions directly via
   tablegen in the scheduling models.

In future, the STIPredicates framework can be used for solving other problems.
Examples of future developments are:
 - Teach how to identify optimizable register-register moves
 - Teach how to identify slow LEA instructions (each subtarget defining its own
   concept of "slow" LEA).
 - Teach how to identify instructions that have undocumented false dependencies
   on the output registers on some processors only.

It is also (in my opinion) an elegant way to expose knowledge to both external
tools like llvm-mca, and codegen passes.
For example, machine schedulers in LLVM could reuse that information when
internally constructing the data dependency graph for a code region.

This new design feature is also an "opt-in" feature. Processor models don't have
to use the new STIPredicates. It has all been designed to be as unintrusive as
possible.

Differential Revision: https://reviews.llvm.org/D52174

llvm-svn: 342555
2018-09-19 15:57:45 +00:00
Jinsong Ji 0594162f32 [NFC] Update comments regarding BufferSize for ProcResources
llvm-svn: 342491
2018-09-18 15:38:56 +00:00
Andrea Di Biagio 9eaf5aa006 [Tablegen][MCInstPredicate] Removed redundant template argument from class TIIPredicate, and implemented verification rules for TIIPredicates.
This patch removes redundant template argument `TargetName` from TIIPredicate.
Tablegen can always infer the target name from the context. So we don't need to
force users of TIIPredicate to always specify it.

This allows us to better modularize the tablegen class hierarchy for the
so-called "function predicates". class FunctionPredicateBase has been added; it
is currently used as a building block for TIIPredicates. However, I plan to
reuse that class to model other function predicate classes too (i.e. not just
TIIPredicates). For example, this can be a first step towards implementing
proper support for dependency breaking instructions in tablegen.

This patch also adds a verification step on TIIPredicates in tablegen.
We cannot have multiple TIIPredicates with the same name. Otherwise, this will
cause build errors later on, when tablegen'd .inc files are included by cpp
files and then compiled.

Differential Revision: https://reviews.llvm.org/D50708

llvm-svn: 339706
2018-08-14 18:36:54 +00:00
Andrea Di Biagio 2c6cbc8bb2 [Tablegen] Replace uses of formatted_raw_ostream with raw_ostream in the predicate expander. NFCI
This is a follow-up of r339552.

As pointed out by Craig in D50566, we don't need a formatted_raw_ostream to
indent strings. We can use instead raw_ostream::indent().

Internally, class PredicateExpander already keeps track of the current
indentation level. Also, the grammar for predicates is well parenthesized, and
therefore we don't need to use a formatted_raw_ostream to continuously track the
column number. Instead we can safely replace all the uses of
formatted_raw_ostream::PadToColumn() with uses of raw_ostream::indent().

By replacing formatted_raw_ostream with a simpler raw_ostream, we also avoid the
implicit check on the newline character on every print to stream.

No functional change intended.

llvm-svn: 339577
2018-08-13 15:13:35 +00:00
Andrea Di Biagio 24d86d8513 [Tablegen][SubtargetEmitter] Improve expansion of predicates of a variant scheduling class.
This patch refactors the logic that expands predicates of a variant scheduling
class.

The idea is to improve the readability of the auto-generated code by removing
redundant parentheses around predicate expressions, and by removing redundant
if(true) statements.

This patch replaces the definition of NoSchedPred in TargetSchedule.td with an
instance of MCSchedPredicate. The new definition is sematically equivalent to
the previous one. The main difference is that now SubtargetEmitter knows that it
represents predicate "true".

Before this patch, we always generated an if (true) for the default transition
of a variant scheduling class.

Example (taken from AArch64GenSubtargetInfo.inc) :

```
if (SchedModel->getProcessorID() == 3) { // CycloneModel
  if ((TII->isScaledAddr(*MI)))
    return 927; // (WriteIS_WriteLD)_ReadBaseRS
  if ((true))
    return 928; // WriteLD_ReadDefault
}
```

Extra parentheses were also generated around the predicate expressions.

With this patch, we get the following auto-generated checks:

```
if (SchedModel->getProcessorID() == 3) { // CycloneModel
  if (TII->isScaledAddr(*MI))
    return 927; // (WriteIS_WriteLD)_ReadBaseRS
  return 928; // WriteLD_ReadDefault
}
```

The new auto-generated code behaves exactly the same as before. So, technically
this is a non functional change.

Differential revision: https://reviews.llvm.org/D50566

llvm-svn: 339552
2018-08-13 11:09:04 +00:00
Andrea Di Biagio 8bdfd52ba7 [Tablegen][SubtargetEmitter] refactor method `emitSchedModelHelpersImpl()`. NFCI
Part of the logic has been moved to helper functions to (hopefully) improve
readability.
Added a few code comments to better describe how the algorithm works.

No functional change intended.

llvm-svn: 339421
2018-08-10 10:43:43 +00:00
Clement Courbet 5eeed77f87 [TableGen] Emit a fatal error on inconsistencies in resource units vs cycles.
Summary:
For targets I'm not familiar with, I've automatically made the "default to 1 for each resource" behaviour explicit in the td files.
For more obvious cases, I've ventured a fix.

Some notes:
 - Exynos is especially fishy.
 - AArch64SchedThunderX2T99.td had some truncated entries. If I understand correctly, the person who wrote that interpreted the ResourceCycle as a range. I made the decision to use the upper/lower bound for consistency with the 'Latency' value. I'm sure there is a better choice.
 - The change to X86ScheduleBtVer2.td is an NFC, it just makes values more explicit.

Also see PR37310.

Reviewers: RKSimon, craig.topper, javed.absar

Subscribers: kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D46356

llvm-svn: 334586
2018-06-13 09:41:49 +00:00
Andrea Di Biagio be8616f5f2 [MCSchedule] Add the ability to compute the latency and throughput information for MCInst.
This patch extends the MCSchedModel API with new methods that can be used to
obtain the latency and reciprocal througput information for an MCInst.

Scheduling models have recently gained the ability to resolve variant scheduling
classes associated with MCInst objects. Before, models were only able to resolve
a variant scheduling class from a MachineInstr object.

This patch is mainly required by D47374 to avoid regressing a pair of x86
specific -print-schedule tests for btver2. Patch D47374 introduces a new variant
class to teach the btver scheduling model (x86 target) how to correctly compute
the latency profile for some zero-idioms using the new scheduling predicates.

The new methods added by this patch would be mainly used by llc when flag
-print-schedule is specified. In particular, tests that contain inline assembly
require that code is parsed at code emission stage into a sequence of MCInst.
That forces the print-schedule functionality to query the latency/rthroughput
information for MCInst instructions too. If we don't expose this new API, then
we lose "-print-schedule" test coverage as soon as variant scheduling classes
are added to the x86 models.

The tablegen SubtargetEmitter changes teaches how to query latency profile
information using a object that derives from TargetSubtargetInfo. Note that this
should really have been part of r333286. To avoid code duplication, the logic
that "resolves" variant scheduling classes for MCInst, has been moved to a
common place in MC. That logic is used by the "resolveVariantSchedClass" methods
redefined in override by the tablegen'd GenSubtargetInfo classes.

Differential Revision: https://reviews.llvm.org/D47536

llvm-svn: 333650
2018-05-31 13:30:42 +00:00
Andrea Di Biagio df8e919957 [Tablegen] Avoid generating empty switch statements. NFC
This fixes an MSVC warning (warning C4065: switch statement contains 'default'
but no 'case' labels) introduced with revision 333293.

llvm-svn: 333363
2018-05-27 19:08:12 +00:00
Andrea Di Biagio 6c40057bd0 [Tablegen][SubtargetEmitter] Add a default case to the auto-generated switch in MCSubtargetInfo::resolveVariantSchedClass(). NFC
llvm-svn: 333293
2018-05-25 18:25:54 +00:00
Andrea Di Biagio 8f66adecd0 [RFC][Patch 2/3] Add a MCSubtargetInfo hook to resolve variant scheduling classes.
This patch is the second of a sequence of three patches related to LLVM-dev RFC
"MC support for varinat scheduling classes".
https://lists.llvm.org/pipermail/llvm-dev/2018-May/123181.html

The goal of this patch is to enable the resolution of variant classes in MC with
the help of a new method named `MCSubtargetInfo::resolveVariantSchedClass()`.

This patch also teaches the SubtargetEmitter how to automatically generate the
definition of method resolveVariantSchedClass().  That definition is emitted
within a sub-class of MCSubtargetInfo named XXXGenMCSubtargetInfo (where XXX is
the name of the Target).

Differential Revision: https://reviews.llvm.org/D47077

llvm-svn: 333286
2018-05-25 16:02:43 +00:00
Andrea Di Biagio 95140023b5 [RFC][Patch 1/3] Add a new class of predicates for variant scheduling classes.
This patch is the first of a sequence of three patches described by the LLVM-dev
RFC "MC support for variant scheduling classes".
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123181.html

The goal of this patch is to introduce a new class of scheduling predicates for
SchedReadVariant and SchedWriteVariant.

An MCSchedPredicate can be used instead of a normal SchedPredicate to model
checks on the instruction (either a MachineInstr or a MCInst).
Internally, an MCSchedPredicate encapsulates an MCInstPredicate definition.
MCInstPredicate allows the definition of expressions with a well-known semantic,
that can be used to generate code for both MachineInstr and MCInst.

This is the first step toward teaching to tools like lllvm-mca how to resolve
variant scheduling classes.

Differential Revision: https://reviews.llvm.org/D46695

llvm-svn: 333282
2018-05-25 15:55:37 +00:00
Nicola Zaghen d34e60ca85 Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
2018-05-14 12:53:11 +00:00
Andrea Di Biagio b31f918979 [Tablegen] SubtargetEmitter: move the logic that prints predicates for variant scheduling classes to helper functions. NFC
llvm-svn: 330968
2018-04-26 18:03:24 +00:00
Simon Pilgrim b04cd1b9f3 [llvm-exegesis] Fix PfmIssueCountersTable creation
This patch ensures that the pfm issue counter tables are the correct size, accounting for the invalid resource entry at the beginning of the resource tables.

It also fixes an issue with pfm failing to match event counters due to a trailing comma added to all the event names.

I've also added a counter comment to each entry as it helps locate problems with the tables.

Note: I don't have access to a SandyBridge test machine, which is the only model to make use of multiple event counters being mapped to a single resource. I don't know if pfm accepts a comma-seperated list or not, but that is what it was doing.

Differential Revision: https://reviews.llvm.org/D45787

llvm-svn: 330317
2018-04-19 10:59:49 +00:00
Clement Courbet bfa20dddcb [MC][TableGen] Fix r329675.
Caught by bots with -Wmissing-braces.

llvm-svn: 329676
2018-04-10 08:43:46 +00:00
Clement Courbet b449379eae [MC][TableGen] Add optional libpfm counter names for ProcResUnits.
Summary:
Subtargets can define the libpfm counter names that can be used to
measure cycles and uops issued on ProcResUnits.
This allows making llvm-exegesis available on more targets.
Fixes PR36984.

Reviewers: gchatelet, RKSimon, andreadb, craig.topper

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45360

llvm-svn: 329675
2018-04-10 08:16:37 +00:00
Mandeep Singh Grang 1b0e2f2a20 [TableGen] Change std::sort to llvm::sort in response to r327219
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.

Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.

Reviewers: stoklund, kparzysz, dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45144

llvm-svn: 329451
2018-04-06 20:18:05 +00:00
Andrea Di Biagio 9730bb8dd8 Fix the buildbots after r329304.
llvm-svn: 329306
2018-04-05 15:53:31 +00:00
Andrea Di Biagio c74ad502ce [MC][Tablegen] Allow models to describe the retire control unit for llvm-mca.
This patch adds the ability to describe properties of the hardware retire
control unit.

Tablegen class RetireControlUnit has been added for this purpose (see
TargetSchedule.td).

A RetireControlUnit specifies the size of the reorder buffer, as well as the
maximum number of opcodes that can be retired every cycle.

A zero (or negative) value for the reorder buffer size means: "the size is
unknown". If the size is unknown, then llvm-mca defaults it to the value of
field SchedMachineModel::MicroOpBufferSize.  A zero or negative number of
opcodes retired per cycle means: "there is no restriction on the number of
instructions that can be retired every cycle".

Models can optionally specify an instance of RetireControlUnit. There can only
be up-to one RetireControlUnit definition per scheduling model.

Information related to the RCU (RetireControlUnit) is stored in (two new fields
of) MCExtraProcessorInfo.  llvm-mca loads that information when it initializes
the DispatchUnit / RetireControlUnit (see Dispatch.h/Dispatch.cpp).

This patch fixes PR36661.

Differential Revision: https://reviews.llvm.org/D45259

llvm-svn: 329304
2018-04-05 15:41:41 +00:00
Andrea Di Biagio 8fd4be3ecc [MC] Fix spaces between values printed by EmitRegisterFileInfo.
llvm-svn: 329284
2018-04-05 13:59:52 +00:00
Andrea Di Biagio 378d75ac17 [Tablegen] Slightly refactor method SubtargetEmitter::EmitExtraProcessorInfo.
This patch moves most of the logic from EmitExtraProcessorInfo to a couple of
helper functions. No functional change intended.

llvm-svn: 329173
2018-04-04 11:53:13 +00:00
Andrea Di Biagio 9da4d6db33 [MC][Tablegen] Allow the definition of processor register files in the scheduling model for llvm-mca
This patch allows the description of register files in processor scheduling
models. This addresses PR36662.

A new tablegen class named 'RegisterFile' has been added to TargetSchedule.td.
Targets can optionally describe register files for their processors using that
class. In particular, class RegisterFile allows to specify:
 - The total number of physical registers.
 - Which target registers are accessible through the register file.
 - The cost of allocating a register at register renaming stage.

Example (from this patch - see file X86/X86ScheduleBtVer2.td)

  def FpuPRF : RegisterFile<72, [VR64, VR128, VR256], [1, 1, 2]>

Here, FpuPRF describes a register file for MMX/XMM/YMM registers. On Jaguar
(btver2), a YMM register definition consumes 2 physical registers, while MMX/XMM
register definitions only cost 1 physical register.

The syntax allows to specify an empty set of register classes.  An empty set of
register classes means: this register file models all the registers specified by
the Target.  For each register class, users can specify an optional register
cost. By default, register costs default to 1.  A value of 0 for the number of
physical registers means: "this register file has an unbounded number of
physical registers".

This patch is structured in two parts.

* Part 1 - MC/Tablegen *

A first part adds the tablegen definition of RegisterFile, and teaches the
SubtargetEmitter how to emit information related to register files.

Information about register files is accessible through an instance of
MCExtraProcessorInfo.
The idea behind this design is to logically partition the processor description
which is only used by external tools (like llvm-mca) from the processor
information used by the llvm machine schedulers.
I think that this design would make easier for targets to get rid of the extra
processor information if they don't want it.

* Part 2 - llvm-mca related *

The second part of this patch is related to changes to llvm-mca.

The main differences are:
 1) class RegisterFile now needs to take into account the "cost of a register"
when allocating physical registers at register renaming stage.
 2) Point 1. triggered a minor refactoring which lef to the removal of the
"maximum 32 register files" restriction.
 3) The BackendStatistics view has been updated so that we can print out extra
details related to each register file implemented by the processor.

The effect of point 3. is also visible in tests register-files-[1..5].s.

Differential Revision: https://reviews.llvm.org/D44980

llvm-svn: 329067
2018-04-03 13:36:24 +00:00
Craig Topper 37eeb32046 [TableGen] Don't capture returned std::vectors by const reference.
The full vector is being returned not a reference. So the reference was just a to a temporary.

llvm-svn: 328275
2018-03-23 00:02:45 +00:00
Sylvestre Ledru 543f15b028 Fix some user facing typos
llvm-svn: 327776
2018-03-17 17:30:08 +00:00
Andrea Di Biagio 30e94029d8 [MCSchedule] Always generate processor resource names.
With this patch, the tablegen 'SubtargetEmitter' always generates processor
resource names. 
The impact of this patch on the code size of other llvm tools is small.  I have
observed an average increase of 0.03% in code size when doing a release build of
LLVM (on windows, using MSVC) with all the default backends.

This change is done in preparation for the upcoming llvm-mca patch.

llvm-svn: 326993
2018-03-08 10:38:45 +00:00
Benjamin Kramer b941ababce Shrink various scheduling tables by using narrower types.
16 bits ought to be enough for everyone. This shrinks clang by ~1MB.

llvm-svn: 325941
2018-02-23 19:32:56 +00:00
Clement Courbet 873aa11dd9 [TargetSchedule] Fix r324582.
Increment was using the wrong NumUnits (the one from the ProcResGroup
and not the subunit).

llvm-svn: 324727
2018-02-09 10:28:46 +00:00
David Blaikie e6503d87da Fix missing field initializer warning in TableGen SubtargetEmitter
llvm-svn: 324643
2018-02-08 19:57:05 +00:00
Clement Courbet 39911e2ee6 [TargetSchedule] Expose sub-units of a ProcResGroup in MCProcResourceDesc.
Summary:
Right now using a ProcResource automatically counts as usage of all
super ProcResGroups. All this is done during codegen, so there is no
way for schedulers to get this information at runtime.

This adds the information of which individual ProcRes units are
contained in a ProcResGroup in MCProcResourceDesc.

Reviewers: gchatelet

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D43023

llvm-svn: 324582
2018-02-08 08:46:48 +00:00
Evandro Menezes 9dc54e25f0 [TableGen] Improve error reporting
When searching for a resource unit, use the reference location instead of
the definition location in case of an error.

Differential revision: https://reviews.llvm.org/D40263

llvm-svn: 318803
2017-11-21 21:33:52 +00:00
Craig Topper 01ebd9b7f7 [TableGen] Use Twine instead of std::string concatenation in two calls to PrintFatalError.
llvm-svn: 316697
2017-10-26 20:49:36 +00:00