The old method used by X86TTI to determine partial-unrolling thresholds was
messy (because it worked by testing target features), and also would not
correctly identify the target CPU if certain target features were disabled.
After some discussions on IRC with Chandler et al., it was decided that the
processor scheduling models were the right containers for this information
(because it is often tied to special uop dispatch-buffer sizes).
This does represent a small functionality change:
- For generic x86-64 (which uses the SB model and, thus, will get some
unrolling).
- For AMD cores (because they still currently use the SB scheduling model)
- For Haswell (based on benchmarking by Louis Gerbarg, it was decided to bump
the default threshold to 50; we're working on a test case for this).
Otherwise, nothing has changed for any other targets. The logic, however, has
been moved into BasicTTI, so other targets may now also opt-in to this
functionality simply by setting LoopMicroOpBufferSize in their processor
model definitions.
llvm-svn: 208289
Ideally, the machinel model is added at the time the instructions are
defined. But many instructions in X86InstrSSE.td still need a model.
Without this workaround the scheduler asserts because x86 already has
itinerary classes for these instructions, indicating they should be
modeled by the scheduler. Since we use the new machine model for other
instructions, it expects a new machine model for these too.
llvm-svn: 191391
Replace the ill-defined MinLatency and ILPWindow properties with
with straightforward buffer sizes:
MCSchedMode::MicroOpBufferSize
MCProcResourceDesc::BufferSize
These can be used to more precisely model instruction execution if desired.
Disabled some misched tests temporarily. They'll be reenabled in a few commits.
llvm-svn: 184032
Don't output data if we are supposed to ignore the record.
Reapply of 183255, I don't think this was causing the tablegen segfault on linux
testers.
llvm-svn: 183311
Super-resources and resource groups are two ways of expressing
overlapping sets of processor resources. Now we generate table entries
the same way for both so the scheduler never needs to explicitly check
for super-resources.
llvm-svn: 180162
We always supported a mixture of the old itinerary model and new
per-operand model, but it required a level of indirection to map
itinerary classes to SchedRW lists. This was done for ARM A9.
Now we want to define x86 SchedRW lists, with the goal of removing its
itinerary classes, but still support the itineraries in the mean
time. When I original developed the model, Atom did not have
itineraries, so there was no reason to expect this requirement.
llvm-svn: 177226
This allows abitrary groups of processor resources. Using something in
a subset automatically counts againts the superset. Currently, this
only works if the superset is also a ProcResGroup as opposed to a
SuperUnit.
This allows SandyBridge to be expressed naturally, which will be
checked in shortly.
def SBPort01 : ProcResGroup<[SBPort0, SBPort1]>;
def SBPort15 : ProcResGroup<[SBPort1, SBPort5]>;
def SBPort23 : ProcResGroup<[SBPort2, SBPort3]>;
def SBPort015 : ProcResGroup<[SBPort0, SBPort1, SBPort5]>;
llvm-svn: 177112
Fix the way resources are counted. I'm taking some time to cleanup the
way MachineScheduler handles in-order machine resources. Eventually
we'll need more PPC/Atom test cases in tree.
llvm-svn: 176390
This was an experimental option, but needs to be defined
per-target. e.g. PPC A2 needs to aggressively hide latency.
I converted some in-order scheduling tests to A2. Hal is working on
more test cases.
llvm-svn: 171946
"../llvm-git/utils/TableGen/CodeGenSchedule.cpp", line 1594.12: 1540-0218 (S) The call does not match any parameter list for "operator+".
"../llvm-git/include/llvm/ADT/STLExtras.h", line 130.1: 1540-1283 (I) "template <class _Iterator, class Func> llvm::operator+(mapped_iterator<_Iterator,Func>::difference_type, const mapped_iterator<_Iterator,Func> &)" is not a viable candidate.
Patch by Kai.
llvm-svn: 167311
Most places can use PrintFatalError as the unwinding mechanism was not
used for anything other than printing the error. The single exception
was CodeGenDAGPatterns.cpp, where intermediate errors during type
resolution were ignored to simplify incremental platform development.
This use is replaced by an error flag in TreePattern and bailout earlier
in various places if it is set.
llvm-svn: 166712
A processor can now arbitrarily alias one SchedWrite onto
another. Only the SchedAlias definition need be within the processor
model. The aliased SchedWrite may be a SchedVariant, WriteSequence, or
transitively refer to another alias.
llvm-svn: 165179
Now where we used to call ReInitMCSubtargetInfo, we actually recompute
the same information as InitMCSubtargetInfo instead of only setting
the feature bits.
llvm-svn: 164105
Map the CodeGenSchedule object model onto data tables. The structure
of the data tables is defined in MC, so for convenience we include
MCSchedule.h. The alternative is maintaining a redundant copy of the
table structure definitions. Mapping the object model onto data tables
is sufficiently complicated that it should not be interleaved with
emitting source code. This avoids major problem with the backend for
itinerary generation.
llvm-svn: 164059
subtarget CPU descriptions and support new features of
MachineScheduler.
MachineModel has three categories of data:
1) Basic properties for coarse grained instruction cost model.
2) Scheduler Read/Write resources for simple per-opcode and operand cost model (TBD).
3) Instruction itineraties for detailed per-cycle reservation tables.
These will all live side-by-side. Any subtarget can use any
combination of them. Instruction itineraries will not change in the
near term. In the long run, I expect them to only be relevant for
in-order VLIW machines that have complex contraints and require a
precise scheduling/bundling model. Once itineraries are only actively
used by VLIW-ish targets, they could be replaced by something more
appropriate for those targets.
This tablegen backend rewrite sets things up for introducing
MachineModel type #2: per opcode/operand cost model.
llvm-svn: 159891
