Class InstrBuilder wrongly assumed that llvm targets were always able to return
a non-null pointer when createMCInstrAnalysis() was called on them.
This was causing crashes when simulating executions for targets that don't
provide an MCInstrAnalysis object.
This patch fixes the issue by making MCInstrAnalysis optional.
llvm-svn: 349352
Refactor the scheduling predicates based on `MCInstPredicate`. In this
case, for the Exynos processors.
Differential revision: https://reviews.llvm.org/D55345
llvm-svn: 348774
It was failing as below. Adding a triple seems to help.
--
: 'RUN: at line 2'; /work/llvm.combined/build.release/bin/llvm-mca -march=aarch64 -mcpu=exynos-m1 -resource-pressure=false < /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s | /work/llvm.combined/build.release/bin/FileCheck /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s -check-prefixes=ALL,M1
: 'RUN: at line 3'; /work/llvm.combined/build.release/bin/llvm-mca -march=aarch64 -mcpu=exynos-m3 -resource-pressure=false < /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s | /work/llvm.combined/build.release/bin/FileCheck /work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s -check-prefixes=ALL,M3
--
Exit Code: 1
Command Output (stderr):
--
/work/llvm.combined/llvm/test/tools/llvm-mca/AArch64/Exynos/direct-branch.s:36:12: error: M1-NEXT: expected string not found in input
^
<stdin>:21:2: note: scanning from here
1 0 0.25 b Ltmp0
^
--
llvm-svn: 348577
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
This change is in preparation for a patch that fixes PR36666.
llvm-mca currently doesn't know if a buffered processor resource describes a
load or store queue. So, any dynamic dispatch stall caused by the lack of
load/store queue entries is normally reported as a generic SCHEDULER stall. See for
example the -dispatch-stats output from the two tests modified by this patch.
In future, processor models will be able to tag processor resources that are
used to describe load/store queues. That information would then be used by
llvm-mca to correctly classify dynamic dispatch stalls caused by the lack of
tokens in the LS.
llvm-svn: 347662
Refactor the scheduling predicates based on `MCInstPredicate`. In this
case, `AArch64InstrInfo::hasShiftedReg()`.
Differential revision: https://reviews.llvm.org/D54820
llvm-svn: 347598
Refactor the scheduling predicates based on `MCInstPredicate`. In this
case, `AArch64InstrInfo::isScaledAddr()`
Differential revision: https://reviews.llvm.org/D54777
llvm-svn: 347597
By default, llvm-mca conservatively assumes that a register operand from the
variadic sequence is both a register read and a register write. That is because
MCInstrDesc doesn't describe extra variadic operands; we don't have enough
dataflow information to tell which register operands from the variadic sequence
is a definition, and which is a use instead.
However, if a variadic instruction is flagged 'mayStore' (but not 'mayLoad'),
and it has no 'unmodeledSideEffects', then llvm-mca (very) optimistically
assumes that any register operand in the variadic sequence is a register read
only. Conversely, if a variadic instruction is marked as 'mayLoad' (but not
'mayStore'), and it has no 'unmodeledSideEffects', then llvm-mca optimistically
assumes that any extra register operand is a register definition only.
These assumptions work quite well for variadic load/store multiple instructions
defined by the ARM backend.
llvm-svn: 347522
`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
With this change, InstrBuilder emits an error if the MCInst sequence contains an
instruction with a variadic opcode, and a non-zero number of variadic operands.
Currently we don't know how to correctly analyze variadic opcodes. The problem
with variadic operands is that there is no information for them in the opcode
descriptor (i.e. MCInstrDesc). That means, we don't know which variadic operands
are defs, and which are uses.
In future, we could try to conservatively assume that any extra register
operands is both a register use and a register definition.
This patch fixes a subtle bug in the evaluation of read/write operands for ARM
VLD1 with implicit index update. Added test vld1-index-update.s
llvm-svn: 347503
RetireControlUnitStatistics now reports extra information about the ROB and the
avg/maximum number of entries consumed over the entire simulation.
Example:
Retire Control Unit - number of cycles where we saw N instructions retired:
[# retired], [# cycles]
0, 109 (17.9%)
1, 102 (16.7%)
2, 399 (65.4%)
Total ROB Entries: 64
Max Used ROB Entries: 35 ( 54.7% )
Average Used ROB Entries per cy: 32 ( 50.0% )
Documentation in llvm/docs/CommandGuide/llvmn-mca.rst has been updated to
reflect this change.
llvm-svn: 347493
This patch fixes an invalid memory read introduced by r346487.
Before this patch, partial register write had to query the latency of the
dependent full register write by calling a method on the full write descriptor.
However, if the full write is from an already retired instruction, chances are
that the EntryStage already reclaimed its memory.
In some parial register write tests, valgrind was reporting an invalid
memory read.
This change fixes the invalid memory access problem. Writes are now responsible
for tracking dependent partial register writes, and notify them in the event of
instruction issued.
That means, partial register writes no longer need to query their associated
full write to check when they are ready to execute.
Added test X86/BtVer2/partial-reg-update-7.s
llvm-svn: 347459
When looking at the tests committed by Roman at r346587, I noticed that numbers
reported by the resource pressure for PdAGU01 were wrong.
In particular, according to the aut-generated CHECK lines in tests
memcpy-like-test.s and store-throughput.s, resource pressure for PdAGU01
was not uniformly distributed among the two AGEN pipes.
It turns out that the reason why pressure was not correctly distributed, was
because the "resource selection strategy" object associated with PdAGU01 was not
correctly updated on the event of AGEN pipe used.
As a result, llvm-mca was not simulating a round-robin pipeline allocation for
PdAGU01. Instead, PdAGU1 was always prioritized over PdAGU0.
This patch fixes the issue; now processor resource strategy objects for
resources declaring multiple units, are correctly notified in the event of
"resource used".
llvm-svn: 346650
There are two AGU units, and per 1cy, there can be either two loads,
or a load and a store; but not two stores, or two loads and a store.
Additionally, loads shouldn't affect the store scheduler and vice versa.
(but *should* affect the PdEX scheduler.)
Required rL346545.
Fixes https://bugs.llvm.org/show_bug.cgi?id=39465
llvm-svn: 346587
As noted by Andrea Di Biagio in https://bugs.llvm.org/show_bug.cgi?id=39465
both the loads and stores occupy both the store and load queues.
This is clearly wrong.
llvm-svn: 346425
During review it was noted that while it appears that
the Piledriver can do two [consecutive] loads per cycle,
it can only do one store per cycle. It was suggested
that the sched model incorrectly models that,
but it was opted to fix this afterwards.
These tests show that the two consecutive loads are
modelled correctly, and one consecutive stores is not
modelled incorrectly. Unless i'm missing the point.
https://bugs.llvm.org/show_bug.cgi?id=39465
llvm-svn: 346404
This patch teaches view RegisterFileStatistics how to report events for
optimizable register moves.
For each processor register file, view RegisterFileStatistics reports the
following extra information:
- Number of optimizable register moves
- Number of register moves eliminated
- Number of zero moves (i.e. register moves that propagate a zero)
- Max Number of moves eliminated per cycle.
Differential Revision: https://reviews.llvm.org/D53976
llvm-svn: 345865
Adding the baseline tests in a preparatory NFC commit,
so that the actual commit shows the *diff*.
Yes, i'm aware that a few of these codegen-based sched tests
are testing wrong instructions, i will fix that afterwards.
For https://reviews.llvm.org/D52779
llvm-svn: 345462
Summary:
This renames the IsParsingMSInlineAsm member variable of AsmLexer to
LexMasmIntegers and moves it up to MCAsmLexer. This is the only behavior
controlled by that variable. I added a public setter, so that it can be
set from outside or from the llvm-mc command line. We may need to
arrange things so that users can get this behavior from clang, but
that's future work.
I also put additional hex literal lexing functionality under this flag
to fix PR32973. It appears that this hex literal parsing wasn't intended
to be enabled in non-masm-style blocks.
Now, masm integers (0b1101 and 0ABCh) work in __asm blocks from clang,
but 0b label references work when using .intel_syntax in standalone .s
files.
However, 0b label references will *not* work from __asm blocks in clang.
They will work from GCC inline asm blocks, which it sounds like is
important for Crypto++ as mentioned in PR36144.
Essentially, we only lex masm literals for inline asm blobs that use
intel syntax. If the .intel_syntax directive is used inside a gnu-style
inline asm statement, masm literals will not be lexed, which is
compatible with gas and llvm-mc standalone .s assembly.
This fixes PR36144 and PR32973.
Reviewers: Gerolf, avt77
Subscribers: eraman, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D53535
llvm-svn: 345189
A new class named InstructionError has been added to Support.h in order to
improve the error reporting from class InstrBuilder.
The llvm-mca driver is responsible for handling InstructionError objects, and
printing them out to stderr.
The goal of this patch is to remove all the remaining error handling logic from
the library code.
In particular, this allows us to:
- Simplify the logic in InstrBuilder by removing a needless dependency from
MCInstrPrinter.
- Centralize all the error halding logic in a new function named 'runPipeline'
(see llvm-mca.cpp).
This is also a first step towards generalizing class InstrBuilder, so that in
future, we will be able to reuse its logic to also "lower" MachineInstr to
mca::Instruction objects.
Differential Revision: https://reviews.llvm.org/D53585
llvm-svn: 345129
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
These should test all the optimizable moves on Jaguar.
A follow-up patch will teach how to recognize these optimizable register moves.
llvm-svn: 344144
Currently we hardcode instructions with ReadAfterLd if the register operands don't need to be available until the folded load has completed. This doesn't take into account the different load latencies of different memory operands (PR36957).
This patch adds a ReadAfterFold def into X86FoldableSchedWrite to replace ReadAfterLd, allowing us to specify the load latency at a scheduler class level.
I've added ReadAfterVec*Ld classes that match the XMM/Scl, XMM and YMM/ZMM WriteVecLoad classes that we currently use, we can tweak these values in future patches once this infrastructure is in place.
Differential Revision: https://reviews.llvm.org/D52886
llvm-svn: 343868
Evandro Menezes