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Commit Graph

97 Commits

Author SHA1 Message Date
Artem Belevich
f14e0f0a96 [NVPTX] Added NVVMIntrRange pass
NVVMIntrRange adds !range metadata to calls of NVVM intrinsics
that return values within known limited range.

This allows LLVM to generate optimal code for indexing arrays
based on tid/ctaid which is a frequently used pattern in CUDA code.

Differential Revision: http://reviews.llvm.org/D20644

llvm-svn: 270872
2016-05-26 17:02:56 +00:00
Rafael Espindola
22e87bbb08 Delete Reloc::Default.
Having an enum member named Default is quite confusing: Is it distinct
from the others?

This patch removes that member and instead uses Optional<Reloc> in
places where we have a user input that still hasn't been maped to the
default value, which is now clear has no be one of the remaining 3
options.

llvm-svn: 269988
2016-05-18 22:04:49 +00:00
Matthias Braun
556abb392a CodeGen: Move TargetPassConfig from Passes.h to an own header; NFC
Many files include Passes.h but only a fraction needs to know about the
TargetPassConfig class. Move it into an own header. Also rename
Passes.cpp to TargetPassConfig.cpp while we are at it.

llvm-svn: 269011
2016-05-10 03:21:59 +00:00
Justin Lebar
c5f2ca9cfc [NVPTX] Run NVVMReflect at the beginning of IR passes.
Summary:
Currently the NVVMReflect pass is run at the beginning of our backend
passes.  But really, it should be run as early as possible, as it's
simply resolving an "if" statement in code.  So copy it into
TargetMachine::addEarlyAsPossiblePasses.

We still run it at the beginning of the backend passes, since it's
needed for correctness when lowering to nvptx.

(Specifically, NVVMReflect changes each call to the __nvvm_reflect
function or llvm.nvvm.reflect intrinsic into an integer constant, based
on the pass's configuration.  Clearly we miss many optimization
opportunities if we perform this transformation at the beginning of
codegen.)

Reviewers: rnk

Subscribers: tra, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D18616

llvm-svn: 267765
2016-04-27 19:13:37 +00:00
Jingyue Wu
db7e23c040 [NVPTX] Fix some usages of CodeGenOpt::None.
NVPTXLowerKernelArgs is required for correctness, so it should not be guarded
by CodeGenOpt::None.

NVPTXPeephole is optimization only, so it should be skipped when
CodeGenOpt::None.

llvm-svn: 267619
2016-04-26 22:59:25 +00:00
Sanjoy Das
7e1b5ea5d3 Disable the PatchableFunction pass for NVPTX & Wasm
PatchableFunction requires AllVRegsAllocated that these targets don't
provide.

llvm-svn: 266720
2016-04-19 06:24:58 +00:00
Derek Schuff
9f833b6097 Introduce MachineFunctionProperties and the AllVRegsAllocated property
MachineFunctionProperties represents a set of properties that a MachineFunction
can have at particular points in time. Existing examples of this idea are
MachineRegisterInfo::isSSA() and MachineRegisterInfo::tracksLiveness() which
will eventually be switched to use this mechanism.
This change introduces the AllVRegsAllocated property; i.e. the property that
all virtual registers have been allocated and there are no VReg operands
left.

With this mechanism, passes can declare that they require a particular property
to be set, or that they set or clear properties by implementing e.g.
MachineFunctionPass::getRequiredProperties(). The MachineFunctionPass base class
verifies that the requirements are met, and handles the setting and clearing
based on the delcarations. Passes can also directly query and update the current
properties of the MF if they want to have conditional behavior.

This change annotates the target-independent post-regalloc passes; future
changes will also annotate target-specific ones.

Reviewers: qcolombet, hfinkel

Differential Revision: http://reviews.llvm.org/D18421

llvm-svn: 264593
2016-03-28 17:05:30 +00:00
Jingyue Wu
2526430a5c [NVPTX] Adds a new address space inference pass.
Summary:
The old address space inference pass (NVPTXFavorNonGenericAddrSpaces) is unable
to convert the address space of a pointer induction variable. This patch adds a
new pass called NVPTXInferAddressSpaces that overcomes that limitation using a
fixed-point data-flow analysis (see the file header comments for details).

The new pass is experimental and not enabled by default. Users can turn
it on by setting the -nvptx-use-infer-addrspace flag of llc.

Reviewers: jholewinski, tra, jlebar

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D17965

llvm-svn: 263916
2016-03-20 20:59:20 +00:00
Chandler Carruth
d0ae36e8de [PM] Port GVN to the new pass manager, wire it up, and teach a couple of
tests to run GVN in both modes.

This is mostly the boring refactoring just like SROA and other complex
transformation passes. There is some trickiness in that GVN's
ValueNumber class requires hand holding to get to compile cleanly. I'm
open to suggestions about a better pattern there, but I tried several
before settling on this. I was trying to balance my desire to sink as
much implementation detail into the source file as possible without
introducing overly many layers of abstraction.

Much like with SROA, the design of this system is made somewhat more
cumbersome by the need to support both pass managers without duplicating
the significant state and logic of the pass. The same compromise is
struck here.

I've also left a FIXME in a doxygen comment as the GVN pass seems to
have pretty woeful documentation within it. I'd like to submit this with
the FIXME and let those more deeply familiar backfill the information
here now that we have a nice place in an interface to put that kind of
documentaiton.

Differential Revision: http://reviews.llvm.org/D18019

llvm-svn: 263208
2016-03-11 08:50:55 +00:00
Jingyue Wu
bb54579422 [NVPTX] Disable performance optimizations when OptLevel==None
Reviewers: jholewinski, tra, eliben

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D16874

llvm-svn: 259749
2016-02-04 04:15:36 +00:00
Eric Christopher
a096f8ec12 constify the Function parameter to the TTI creation callback and
propagate to all callers/users/etc.

llvm-svn: 247864
2015-09-16 23:38:13 +00:00
Artem Belevich
b49e9cf074 [NVPTX] Added run NVVMReflect pass to NVPTX back-end.
The pass is needed to remove __nvvm_reflect calls when we link in
libdevice bitcode that comes with CUDA.

Differential Revision: http://reviews.llvm.org/D11663

llvm-svn: 247072
2015-09-08 21:04:55 +00:00
Jingyue Wu
e5794c4c5a Roll forward r242871
r242871 missed one place that should be guarded with isPhysicalReg. This patch
fixes that.

llvm-svn: 243555
2015-07-29 18:59:09 +00:00
Jingyue Wu
96bbc40a55 Temporarily revert r242871
PR24299

llvm-svn: 243522
2015-07-29 15:26:11 +00:00
Jingyue Wu
a5bed5dde5 [NVPTX] run LSR before straight-line optimizations
Summary:
Straight-line optimizations can simplify the loop body and make LSR's
cost analysis more precise. This significantly improves several Eigen3
CUDA benchmarks.

With this change, EigenContractionKernel runs up to 40% faster
(753ceee5f2/unsupported/Eigen/CXX11/src/Tensor/TensorContractionCuda.h (cl-502)).
EigenConvolutionKernel2D runs up to 10% faster
(753ceee5f2/unsupported/Eigen/CXX11/src/Tensor/TensorConvolution.h (cl-605)).

I have some difficulties writing small tests that benefit from this
reordering due to a seemingly issue with LSR (being discussed at
http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-July/088244.html).

See the review thread for the compilation time impact of GVN. 

Reviewers: eliben, jholewinski

Subscribers: llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D11304

llvm-svn: 242982
2015-07-23 04:59:07 +00:00
Jingyue Wu
45a0757122 [BranchFolding] do not iterate the aliases of virtual registers
Summary:
MCRegAliasIterator only works for physical registers. So, do not run it
on virtual registers.

With this issue fixed, we can resurrect the BranchFolding pass in NVPTX
backend.

Reviewers: jholewinski, bkramer

Subscribers: henryhu, meheff, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D11174

llvm-svn: 242871
2015-07-22 04:16:52 +00:00
Jingyue Wu
e11ca7270f [NVPTX] enable SpeculativeExecution in NVPTX
Summary:
SpeculativeExecution enables a series straight line optimizations (such
as SLSR and NaryReassociate) on conditional code. For example,

  if (...)
    ... b * s ...
  if (...)
    ... (b + 1) * s ...

speculative execution can hoist b * s and (b + 1) * s from then-blocks,
so that we have

  ... b * s ...
  if (...)
    ...
  ... (b + 1) * s ...
  if (...)
    ...

Then, SLSR can rewrite (b + 1) * s to (b * s + s) because after
speculative execution b * s dominates (b + 1) * s.

The performance impact of this change is significant. It speeds up the
benchmarks running EigenFloatContractionKernelInternal16x16
(ba68f42fa6/unsupported/Eigen/CXX11/src/Tensor/TensorContractionCuda.h (cl-526))
by roughly 2%. Some internal benchmarks that have the above code pattern
are improved by up to 40%. No significant slowdowns are observed on
Eigen CUDA microbenchmarks.

Reviewers: jholewinski, broune, eliben

Subscribers: llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D11201

llvm-svn: 242437
2015-07-16 20:13:48 +00:00
Eli Bendersky
901c8f80fc Correct lowering of memmove in NVPTX
This fixes https://llvm.org/bugs/show_bug.cgi?id=24056

Also a bit of refactoring along the way.

Differential Revision: http://reviews.llvm.org/D11220

llvm-svn: 242413
2015-07-16 16:27:19 +00:00
Mehdi Amini
8fce925ea2 Make TargetTransformInfo keeping a reference to the Module DataLayout
DataLayout is no longer optional. It was initialized with or without
a DataLayout, and the DataLayout when supplied could have been the
one from the TargetMachine.

Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.

Reviewers: echristo

Subscribers: jholewinski, llvm-commits, rafael, yaron.keren

Differential Revision: http://reviews.llvm.org/D11021

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 241774
2015-07-09 02:08:42 +00:00
Jingyue Wu
bf15de754a [NVPTX] Move NVPTXPeephole after NVPTXPrologEpilogPass
Summary:
Offset of frame index is calculated by NVPTXPrologEpilogPass. Before
that the correct offset of stack objects cannot be obtained, which
leads to wrong offset if there are more than 2 frame objects. This patch
move NVPTXPeephole after NVPTXPrologEpilogPass. Because the frame index
is already replaced by %VRFrame in NVPTXPrologEpilogPass, we check
VRFrame register instead, and try to remove the VRFrame if there
is no usage after NVPTXPeephole pass.

Patched by Xuetian Weng. 

Test Plan:
Strengthened test/CodeGen/NVPTX/local-stack-frame.ll to check the
offset calculation based on SP and SPL.

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10853

llvm-svn: 241185
2015-07-01 20:08:06 +00:00
Jingyue Wu
7ff7eb51d2 Add NVPTXPeephole pass to reduce unnecessary address cast
Summary:
This patch first change the register that holds local address for stack
frame to %SPL. Then the new NVPTXPeephole pass will try to scan the
following pattern

   %vreg0<def> = LEA_ADDRi64 <fi#0>, 4
   %vreg1<def> = cvta_to_local %vreg0

and transform it into

   %vreg1<def> = LEA_ADDRi64 %VRFrameLocal, 4

Patched by Xuetian Weng

Test Plan: test/CodeGen/NVPTX/local-stack-frame.ll

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: eliben, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10549

llvm-svn: 240587
2015-06-24 20:20:16 +00:00
Jingyue Wu
34412b317e Add NVPTXLowerAlloca pass to convert alloca'ed memory to local address
Summary:
This is done by first adding two additional instructions to convert the
alloca returned address to local and convert it back to generic. Then
replace all uses of alloca instruction with the converted generic
address. Then we can rely NVPTXFavorNonGenericAddrSpace pass to combine
the generic addresscast and the corresponding Load, Store, Bitcast, GEP
Instruction together.

Patched by Xuetian Weng (xweng@google.com). 

Test Plan: test/CodeGen/NVPTX/lower-alloca.ll

Reviewers: jholewinski, jingyue

Reviewed By: jingyue

Subscribers: meheff, broune, eliben, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10483

llvm-svn: 239964
2015-06-17 22:31:02 +00:00
Daniel Sanders
ac381fec59 Replace string GNU Triples with llvm::Triple in TargetMachine. NFC.
Summary:
For the moment, TargetMachine::getTargetTriple() still returns a StringRef.

This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: ted, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10362

llvm-svn: 239554
2015-06-11 19:41:26 +00:00
Daniel Sanders
e37ebd59c5 Replace string GNU Triples with llvm::Triple in MCSubtargetInfo and create*MCSubtargetInfo(). NFC.
Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rafael

Reviewed By: rafael

Subscribers: rafael, ted, jfb, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10311

llvm-svn: 239467
2015-06-10 12:11:26 +00:00
Jingyue Wu
c74965ca17 [NVPTX] run SROA after NVPTXFavorNonGenericAddrSpaces
Summary:
This cleans up most allocas NVPTXLowerKernelArgs emits for byval
parameters.

Test Plan: makes bug21465.ll more stronger to verify no redundant local load/store.

Reviewers: eliben, jholewinski

Reviewed By: eliben, jholewinski

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10322

llvm-svn: 239368
2015-06-09 00:05:56 +00:00
Jingyue Wu
efaa872a9c [NVPTX] roll forward r239082
NVPTXISelDAGToDAG translates "addrspacecast to param" to
NVPTX::nvvm_ptr_gen_to_param

Added an llc test in bug21465.

llvm-svn: 239100
2015-06-04 21:28:26 +00:00
Jingyue Wu
aaaab32848 Revert r239082
llc crashed for NVPTX backend

llvm-svn: 239094
2015-06-04 21:07:08 +00:00
Jingyue Wu
98b56fca22 [NVPTX] kernel pointer arguments point to the global address space
Summary:
With this patch, NVPTXLowerKernelArgs converts a kernel pointer argument to a
pointer in the global address space. This change, along with
NVPTXFavorNonGenericAddrSpaces, allows the NVPTX backend to emit ld.global.*
and st.global.* for accessing kernel pointer arguments.

Minor changes:
1. refactor: extract function convertToPointerInAddrSpace
2. fix a bug in the test case in bug21465.ll

Test Plan: lower-kernel-ptr-arg.ll

Reviewers: eliben, meheff, jholewinski

Reviewed By: jholewinski

Subscribers: wengxt, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D10154

llvm-svn: 239082
2015-06-04 20:19:38 +00:00
Jingyue Wu
6c391c6619 [NaryReassociate] Run EarlyCSE after NaryReassociate
Summary:
This patch made two improvements to NaryReassociate and the NVPTX pipeline

1. Run EarlyCSE/GVN after NaryReassociate to get rid of redundant common
expressions.

2. When adding an instruction to SeenExprs, maps both the SCEV before and after
reassociation to that instruction.

Test Plan: updated @reassociate_gep_nsw in nary-gep.ll

Reviewers: meheff, broune

Reviewed By: broune

Subscribers: dberlin, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D9947

llvm-svn: 238396
2015-05-28 04:56:52 +00:00
Jingyue Wu
f2297fbf03 Resurrect r235688
We should skip vector types which are not SCEVable.

test/CodeGen/NVPTX/sched2.ll passes

llvm-svn: 235695
2015-04-24 04:22:39 +00:00
Jingyue Wu
3bc256d7df Revert r235688
Seems breaking builds

llvm-svn: 235690
2015-04-24 03:26:11 +00:00
Jingyue Wu
6e67398da9 [NVPTX] enable NaryReassociate in NVPTX
Summary:
We run NaryReassociate right after SLSR because SLSR enables many
opportunities for NaryReassociate. For example, in nary-slsr.ll

  foo((a + b) + c);
  foo((a + b * 2) + c);
  foo((a + b * 3) + c);   // 2 muls and 6 adds

after SLSR:

  ab = a + b;
  foo(ab + c);
  ab2 = ab + b;
  foo(ab2 + c);
  ab3 = ab2 + b;
  foo(ab3 + c);           // 6 adds

after NaryReassociate:

  abc = (a + b) + c;
  foo(abc);
  ab2c = abc + b;
  foo(ab2c);
  ab3c = ab2c + b;
  foo(ab3c);              // 4 adds

Test Plan: nary-slsr.ll

Reviewers: jholewinski, eliben

Reviewed By: eliben

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D9066

llvm-svn: 235688
2015-04-24 02:54:06 +00:00
Jingyue Wu
dfd39687b2 [NVPTX] run SeparateConstOffsetFromGEP before SLSR
Summary:
We pick this order because SeparateConstOffsetFromGEP may create more
opportunities for SLSR.

Test Plan:
reassociate-geps-and-slsr.ll
no performance regression on internal benchmarks

Reviewers: meheff

Subscribers: llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D9230

llvm-svn: 235632
2015-04-23 20:00:04 +00:00
Jingyue Wu
fa4f8d3923 [NVPTX] do not run DCE after SLSR and SeparateConstOffsetFromGEP
Summary:
With D9096 and D9101, there's no need to run DCE after SLSR and
SeparateConstOffsetFromGEP.

Test Plan: no regression

Reviewers: jholewinski, meheff

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D9172

llvm-svn: 235415
2015-04-21 20:47:15 +00:00
Eric Christopher
310e3fc262 Simplify the query for a subtarget in the NVPTX pass manager.
llvm-svn: 232876
2015-03-21 03:13:03 +00:00
Mehdi Amini
94c8770ed5 Move the DataLayout to the generic TargetMachine, making it mandatory.
Summary:
I don't know why every singled backend had to redeclare its own DataLayout.
There was a virtual getDataLayout() on the common base TargetMachine, the
default implementation returned nullptr. It was not clear from this that
we could assume at call site that a DataLayout will be available with
each Target.

Now getDataLayout() is no longer virtual and return a pointer to the
DataLayout member of the common base TargetMachine. I plan to turn it into
a reference in a future patch.

The only backend that didn't have a DataLayout previsouly was the CPPBackend.
It now initializes the default DataLayout. This commit is NFC for all the
other backends.

Test Plan: clang+llvm ninja check-all

Reviewers: echristo

Subscribers: jfb, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D8243

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231987
2015-03-12 00:07:24 +00:00
Benjamin Kramer
5b70e6e9c6 NVPTX: move NVPTXAllocaHoisting into the cpp file
Also initialize without using static initialization.

llvm-svn: 231822
2015-03-10 19:20:52 +00:00
Eric Christopher
0d42545048 Remove all use of is64bit off of NVPTXSubtarget and clean up code
accordingly. This changes the constructors of a number of classes
that don't need to know the subtarget's 64-bitness.

llvm-svn: 229787
2015-02-19 00:08:27 +00:00
Eric Christopher
182992e6cc Migrate the NVPTX backend asm printer to a per function subtarget.
This involved moving two non-subtarget dependent features (64-bitness
and the driver interface) to the NVPTX target machine and updating
the uses (or migrating around the subtarget use for ease of review).
Otherwise use the cached subtarget or create a default subtarget
based on the TargetMachine cpu and feature string for the module
level assembler emission.

llvm-svn: 229785
2015-02-19 00:08:14 +00:00
Chandler Carruth
18e8c62883 [PM] Remove the old 'PassManager.h' header file at the top level of
LLVM's include tree and the use of using declarations to hide the
'legacy' namespace for the old pass manager.

This undoes the primary modules-hostile change I made to keep
out-of-tree targets building. I sent an email inquiring about whether
this would be reasonable to do at this phase and people seemed fine with
it, so making it a reality. This should allow us to start bootstrapping
with modules to a certain extent along with making it easier to mix and
match headers in general.

The updates to any code for users of LLVM are very mechanical. Switch
from including "llvm/PassManager.h" to "llvm/IR/LegacyPassManager.h".
Qualify the types which now produce compile errors with "legacy::". The
most common ones are "PassManager", "PassManagerBase", and
"FunctionPassManager".

llvm-svn: 229094
2015-02-13 10:01:29 +00:00
Jingyue Wu
4e99b65428 Add straight-line strength reduction to LLVM
Summary:
Straight-line strength reduction (SLSR) is implemented in GCC but not yet in
LLVM. It has proven to effectively simplify statements derived from an unrolled
loop, and can potentially benefit many other cases too. For example,

LLVM unrolls

  #pragma unroll
  foo (int i = 0; i < 3; ++i) {
    sum += foo((b + i) * s);
  }

into

  sum += foo(b * s);
  sum += foo((b + 1) * s);
  sum += foo((b + 2) * s);

However, no optimizations yet reduce the internal redundancy of the three
expressions:

  b * s
  (b + 1) * s
  (b + 2) * s

With SLSR, LLVM can optimize these three expressions into:

  t1 = b * s
  t2 = t1 + s
  t3 = t2 + s

This commit is only an initial step towards implementing a series of such
optimizations. I will implement more (see TODO in the file commentary) in the
near future. This optimization is enabled for the NVPTX backend for now.
However, I am more than happy to push it to the standard optimization pipeline
after more thorough performance tests.

Test Plan: test/StraightLineStrengthReduce/slsr.ll

Reviewers: eliben, HaoLiu, meheff, hfinkel, jholewinski, atrick

Reviewed By: jholewinski, atrick

Subscribers: karthikthecool, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D7310

llvm-svn: 228016
2015-02-03 19:37:06 +00:00
Chandler Carruth
3ed152b528 [multiversion] Switch all of the targets over to use the
TargetIRAnalysis access path directly rather than implementing getTTI.

This even removes getTTI from the interface. It's more efficient for
each target to just register a precise callback that creates their
specific TTI.

As part of this, all of the targets which are building their subtargets
individually per-function now build their TTI instance with the function
and thus look up the correct subtarget and cache it. NVPTX, R600, and
XCore currently don't leverage this functionality, but its trivial for
them to add it now.

llvm-svn: 227735
2015-02-01 13:20:00 +00:00
Chandler Carruth
ad2d6dd7d3 [PM] Switch the TargetMachine interface from accepting a pass manager
base which it adds a single analysis pass to, to instead return the type
erased TargetTransformInfo object constructed for that TargetMachine.

This removes all of the pass variants for TTI. There is now a single TTI
*pass* in the Analysis layer. All of the Analysis <-> Target
communication is through the TTI's type erased interface itself. While
the diff is large here, it is nothing more that code motion to make
types available in a header file for use in a different source file
within each target.

I've tried to keep all the doxygen comments and file boilerplate in line
with this move, but let me know if I missed anything.

With this in place, the next step to making TTI work with the new pass
manager is to introduce a really simple new-style analysis that produces
a TTI object via a callback into this routine on the target machine.
Once we have that, we'll have the building blocks necessary to accept
a function argument as well.

llvm-svn: 227685
2015-01-31 11:17:59 +00:00
Chandler Carruth
b2d6052871 [PM] Change the core design of the TTI analysis to use a polymorphic
type erased interface and a single analysis pass rather than an
extremely complex analysis group.

The end result is that the TTI analysis can contain a type erased
implementation that supports the polymorphic TTI interface. We can build
one from a target-specific implementation or from a dummy one in the IR.

I've also factored all of the code into "mix-in"-able base classes,
including CRTP base classes to facilitate calling back up to the most
specialized form when delegating horizontally across the surface. These
aren't as clean as I would like and I'm planning to work on cleaning
some of this up, but I wanted to start by putting into the right form.

There are a number of reasons for this change, and this particular
design. The first and foremost reason is that an analysis group is
complete overkill, and the chaining delegation strategy was so opaque,
confusing, and high overhead that TTI was suffering greatly for it.
Several of the TTI functions had failed to be implemented in all places
because of the chaining-based delegation making there be no checking of
this. A few other functions were implemented with incorrect delegation.
The message to me was very clear working on this -- the delegation and
analysis group structure was too confusing to be useful here.

The other reason of course is that this is *much* more natural fit for
the new pass manager. This will lay the ground work for a type-erased
per-function info object that can look up the correct subtarget and even
cache it.

Yet another benefit is that this will significantly simplify the
interaction of the pass managers and the TargetMachine. See the future
work below.

The downside of this change is that it is very, very verbose. I'm going
to work to improve that, but it is somewhat an implementation necessity
in C++ to do type erasure. =/ I discussed this design really extensively
with Eric and Hal prior to going down this path, and afterward showed
them the result. No one was really thrilled with it, but there doesn't
seem to be a substantially better alternative. Using a base class and
virtual method dispatch would make the code much shorter, but as
discussed in the update to the programmer's manual and elsewhere,
a polymorphic interface feels like the more principled approach even if
this is perhaps the least compelling example of it. ;]

Ultimately, there is still a lot more to be done here, but this was the
huge chunk that I couldn't really split things out of because this was
the interface change to TTI. I've tried to minimize all the other parts
of this. The follow up work should include at least:

1) Improving the TargetMachine interface by having it directly return
   a TTI object. Because we have a non-pass object with value semantics
   and an internal type erasure mechanism, we can narrow the interface
   of the TargetMachine to *just* do what we need: build and return
   a TTI object that we can then insert into the pass pipeline.
2) Make the TTI object be fully specialized for a particular function.
   This will include splitting off a minimal form of it which is
   sufficient for the inliner and the old pass manager.
3) Add a new pass manager analysis which produces TTI objects from the
   target machine for each function. This may actually be done as part
   of #2 in order to use the new analysis to implement #2.
4) Work on narrowing the API between TTI and the targets so that it is
   easier to understand and less verbose to type erase.
5) Work on narrowing the API between TTI and its clients so that it is
   easier to understand and less verbose to forward.
6) Try to improve the CRTP-based delegation. I feel like this code is
   just a bit messy and exacerbating the complexity of implementing
   the TTI in each target.

Many thanks to Eric and Hal for their help here. I ended up blocked on
this somewhat more abruptly than I expected, and so I appreciate getting
it sorted out very quickly.

Differential Revision: http://reviews.llvm.org/D7293

llvm-svn: 227669
2015-01-31 03:43:40 +00:00
Eric Christopher
aacfef65cf Move DataLayout back to the TargetMachine from TargetSubtargetInfo
derived classes.

Since global data alignment, layout, and mangling is often based on the
DataLayout, move it to the TargetMachine. This ensures that global
data is going to be layed out and mangled consistently if the subtarget
changes on a per function basis. Prior to this all targets(*) have
had subtarget dependent code moved out and onto the TargetMachine.

*One target hasn't been migrated as part of this change: R600. The
R600 port has, as a subtarget feature, the size of pointers and
this affects global data layout. I've currently hacked in a FIXME
to enable progress, but the port needs to be updated to either pass
the 64-bitness to the TargetMachine, or fix the DataLayout to
avoid subtarget dependent features.

llvm-svn: 227113
2015-01-26 19:03:15 +00:00
Matthias Braun
aa888a6f1e [CodeGen] Add print and verify pass after each MachineFunctionPass by default
Previously print+verify passes were added in a very unsystematic way, which is
annoying when debugging as you miss intermediate steps and allows bugs to stay
unnotice when no verification is performed.

To make this change practical I added the possibility to explicitely disable
verification. I used this option on all places where no verification was
performed previously (because alot of places actually don't pass the
MachineVerifier).
In the long term these problems should be fixed properly and verification
enabled after each pass. I'll enable some more verification in subsequent
commits.

This is the 2nd attempt at this after realizing that PassManager::add() may
actually delete the pass.

llvm-svn: 224059
2014-12-11 21:26:47 +00:00
Rafael Espindola
aa48306a03 This reverts commit r224043 and r224042.
check-llvm was failing.

llvm-svn: 224045
2014-12-11 20:03:57 +00:00
Matthias Braun
42e36608f0 [CodeGen] Add print and verify pass after each MachineFunctionPass by default
Previously print+verify passes were added in a very unsystematic way, which is
annoying when debugging as you miss intermediate steps and allows bugs to stay
unnotice when no verification is performed.

To make this change practical I added the possibility to explicitely disable
verification. I used this option on all places where no verification was
performed previously (because alot of places actually don't pass the
MachineVerifier).
In the long term these problems should be fixed properly and verification
enabled after each pass. I'll enable some more verification in subsequent
commits.

llvm-svn: 224042
2014-12-11 19:42:05 +00:00
Reid Kleckner
6a21619ebc Add out of line virtual destructors to all LLVMTargetMachine subclasses
These recently all grew a unique_ptr<TargetLoweringObjectFile> member in
r221878.  When anyone calls a virtual method of a class, clang-cl
requires all virtual methods to be semantically valid. This includes the
implicit virtual destructor, which triggers instantiation of the
unique_ptr destructor, which fails because the type being deleted is
incomplete.

This is just part of the ongoing saga of PR20337, which is affecting
Blink as well. Because the MSVC ABI doesn't have key functions, we end
up referencing the vtable and implicit destructor on any virtual call
through a class. We don't actually end up emitting the dtor, so it'd be
good if we could avoid this unneeded type completion work.

llvm-svn: 222480
2014-11-20 23:37:18 +00:00
Aditya Nandakumar
b93fb292df This patch changes the ownership of TLOF from TargetLoweringBase to TargetMachine so that different subtargets could share the TLOF effectively
llvm-svn: 221878
2014-11-13 09:26:31 +00:00