Commit Graph

196 Commits

Author SHA1 Message Date
Florian Hahn 89c4dda076
[VPlan] Add GraphTraits impl to traverse through VPRegionBlock.
This patch adds a new iterator to traverse through VPRegionBlocks and a
GraphTraits specialization using the iterator to traverse through
VPRegionBlocks.

Because there is already a GraphTraits specialization for VPBlockBase *
and co, a new VPBlockRecursiveTraversalWrapper helper is introduced.
This allows us to provide a new GraphTraits specialization for that
type. Users can use the new recursive traversal by using this wrapper.

The graph trait visits both the entry block of a region, as well as all
its successors. Exit blocks of a region implicitly have their parent
region's successors. This ensures all blocks in a region are visited
before any blocks in a successor region when doing a reverse post-order
traversal of the graph.

Reviewed By: a.elovikov

Differential Revision: https://reviews.llvm.org/D100175
2021-04-23 17:26:47 +01:00
Sander de Smalen 86729538bd [LV] Let selectVectorizationFactor reason directly on VectorizationFactor.
Rather than maintaining two separate values, a `float` for the per-lane
cost and a Width for the VF, maintain a single VectorizationFactor which
comprises the two and also removes the need for converting an integer value
to float.

This simplifies the query when asking if one VF is more profitable than
another when we want to extend this for scalable vectors (which may
require additional options to determine if e.g. a scalable VF of the
some cost, is more profitable than a fixed VF of the same cost).

The patch isn't entirely NFC because it also fixes an issue in
selectEpilogueVectorizationFactor, where the cost passed to ProfitableVFs
no longer truncates the floating-point cost from `float` to `unsigned` to
then perform the calculation on the truncated cost. It now does
a cost comparison with the correct precision.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D100121
2021-04-20 09:54:45 +01:00
Florian Hahn 6adebe3fd2 [VPlan] Add VPRecipeBase::mayHaveSideEffects.
Add an initial version of a helper to determine whether a recipe may
have side-effects.

Reviewed By: a.elovikov

Differential Revision: https://reviews.llvm.org/D100259
2021-04-15 11:49:40 +01:00
Huihui Zhang d857a81437 [VPlan] Use SetVector for VPExternalDefs to prevent non-determinism.
Use SetVector instead of SmallPtrSet for external definitions created for VPlan.
Doing this can help avoid non-determinism caused by iterating over unordered containers.

This bug was found with reverse iteration turning on,
 --extra-llvm-cmake-variables="-DLLVM_REVERSE_ITERATION=ON".
Failing LLVM-Unit test VPRecipeTest.dump.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99544
2021-03-30 12:10:56 -07:00
Andrei Elovikov 92205cb27f [NFC][VPlan] Guard print routines with "#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)"
Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D98897
2021-03-19 10:50:12 -07:00
Andrei Elovikov 93a9d2de8f [VPlan] Add plain text (not DOT's digraph) dumps
I foresee two uses for this:
1) It's easier to use those in debugger.
2) Once we start implementing more VPlan-to-VPlan transformations (especially
   inner loop massaging stuff), using the vectorized LLVM IR as CHECK targets in
   LIT test would become too obscure. I can imagine that we'd want to CHECK
   against VPlan dumps after multiple transformations instead. That would be
   easier with plain text dumps than with DOT format.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D96628
2021-03-19 10:50:12 -07:00
Mehdi Amini 3614df3537 Revert "[VPlan] Add plain text (not DOT's digraph) dumps"
This reverts commit 6b053c9867.
The build is broken:

ld.lld: error: undefined symbol: llvm::VPlan::printDOT(llvm::raw_ostream&) const
>>> referenced by LoopVectorize.cpp
>>>               LoopVectorize.cpp.o:(llvm::LoopVectorizationPlanner::printPlans(llvm::raw_ostream&)) in archive lib/libLLVMVectorize.a
2021-03-18 19:20:39 +00:00
Andrei Elovikov 6b053c9867 [VPlan] Add plain text (not DOT's digraph) dumps
I foresee two uses for this:
1) It's easier to use those in debugger.
2) Once we start implementing more VPlan-to-VPlan transformations (especially
   inner loop massaging stuff), using the vectorized LLVM IR as CHECK targets in
   LIT test would become too obscure. I can imagine that we'd want to CHECK
   against VPlan dumps after multiple transformations instead. That would be
   easier with plain text dumps than with DOT format.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D96628
2021-03-18 11:33:39 -07:00
Florian Hahn f586de8459
[VPlan] Remove PredInst2Recipe, use VP operands instead. (NFC)
Instead of maintaining a separate map from predicated instructions to
recipes, we can instead directly look at the VP operands. If the operand
comes from a predicated instruction, the operand will be a
VPPredInstPHIRecipe with a VPReplicateRecipe as its operand.
2021-03-16 17:40:35 +00:00
David Sherwood fec0a0adac [SVE][LoopVectorize] Add support for extracting the last lane of a scalable vector
There are certain loops like this below:

  for (int i = 0; i < n; i++) {
    a[i] = b[i] + 1;
    *inv = a[i];
  }

that can only be vectorised if we are able to extract the last lane of the
vectorised form of 'a[i]'. For fixed width vectors this already works since
we know at compile time what the final lane is, however for scalable vectors
this is a different story. This patch adds support for extracting the last
lane from a scalable vector using a runtime determined lane value. I have
added support to VPIteration for runtime-determined lanes that still permit
the caching of values. I did this by introducing a new class called VPLane,
which describes the lane we're dealing with and provides interfaces to get
both the compile-time known lane and the runtime determined value. Whilst
doing this work I couldn't find any explicit tests for extracting the last
lane values of fixed width vectors so I added tests for both scalable and
fixed width vectors.

Differential Revision: https://reviews.llvm.org/D95139
2021-03-05 09:57:56 +00:00
Florian Hahn a6c81d3366
[VPlan] Remove recipes from back to front.
Update the deletion order when destroying VPBasicBlocks. This ensures
recipes that depend on earlier ones in the block are removed first.
Otherwise this may cause issues when recipes have remaining users later
in the block.
2021-03-01 16:06:30 +00:00
Andrei Elovikov 3605b873f6 [NFC][VPlan] Use VPUser to store block's predicate
Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D96529
2021-02-23 11:08:27 -08:00
Florian Hahn 15a74b64df
[VPlan] Manage pairs of incoming (VPValue, VPBB) in VPWidenPHIRecipe.
This patch extends VPWidenPHIRecipe to manage pairs of incoming
(VPValue, VPBasicBlock) in the VPlan native path. This is made possible
because we now directly manage defined VPValues for recipes.

By keeping both the incoming value and block in the recipe directly,
code-generation in the VPlan native path becomes independent of the
predecessor ordering when fixing up non-induction phis, which currently
can cause crashes in the VPlan native path.

This fixes PR45958.

Reviewed By: sguggill

Differential Revision: https://reviews.llvm.org/D96773
2021-02-22 09:44:25 +00:00
Florian Hahn edc92a1c42
[LV] Remove VPCallback.
Now that all state for generated instructions is managed directly in
VPTransformState, VPCallBack is no longer needed. This patch updates the
last use of `getOrCreateScalarValue` to instead manage the value
directly in VPTransformState and removes VPCallback.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D95383
2021-02-19 12:50:41 +00:00
Florian Hahn f64c626069
[VPlan] Remove unused Phi member from VPWidenPHIRecipe (NFC).
The member is not needed any longer after recent changes.
2021-02-16 13:53:06 +00:00
Florian Hahn 54a14c264a
[VPlan] Manage scalarized values using VPValues.
This patch updates codegen to use VPValues to manage the generated
scalarized instructions.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D92285
2021-02-16 09:04:10 +00:00
Florian Hahn 85fe5c9345
[VPlan] Make VPRecipeBase inherit from VPUser directly (NFC).
The individual recipes have been updated to manage their operands using
VPUser a while back. Now that the transition is done, we can instead
make VPRecipeBase a VPUser and get rid of the toVPUser helper.
2021-02-12 13:06:58 +00:00
Florian Hahn fd8afa41eb
[VPlan] Use VPUser to manage CondBit
VP blocks keep track of a condition, which is a VPValue. This patch
updates VPBlockBase to manage the value using VPUser, so
replaceAllUsesWith properly updates the condition bit as well.

This is required to enable VP2VP transformations and it helps with
simplifying some of the code required to manage condition bits.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D95382
2021-02-09 21:53:50 +00:00
Florian Hahn 3bb6dc0b26
[LV] Replace some uses of VectorLoopValueMap with VPTransformState (NFC)
This patch updates some places where VectorLoopValueMap is accessed
directly to instead go through VPTransformState.

As we move towards managing created values exclusively in VPTransformState,
this ensures the use always can fetch the correct value.

This is in preparation for D92285, which switches to managing scalarized
values through VPValues.

In the future, the various fix* functions should be moved directly into
the VPlan codegen stage.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D95757
2021-02-07 18:28:21 +00:00
Florian Hahn daaa0e3501
[VPlan] Manage induction value creation using VPValues.
This patch updates the induction value creation to use VPValues of
recipes to map the created values. This should bring is one step closer
to being able to optimize induction recipes directly in VPlan.

Currently widenIntOrFpInduction also generates vector values for a cast
of the induction, if it exists. Make this explicit by adding the cast
instruction to the values defined by the recipe.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D92284
2021-02-03 17:45:03 +00:00
David Sherwood d4626eb0bd [VPlan][NFC] Introduce constructors for VPIteration
This patch adds constructors to VPIteration as a cleaner way of
initialising the struct and replaces existing constructions of
the form:

  {Part, Lane}

with

  VPIteration(Part, Lane)

I have also added a default constructor, which is used by VPlan.cpp
when deciding whether to replicate a block or not.

This refactoring will be required in a later patch that adds more
members and functions to VPIteration.

Differential Revision: https://reviews.llvm.org/D95676
2021-02-03 08:52:27 +00:00
Sanjay Patel ab93c18c12 [LoopVectorize] use IR fast-math-flags exclusively (not FP function attributes)
I am trying to untangle the fast-math-flags propagation logic
in the vectorizers (see a6f022127 for SLP).

The loop vectorizer has a mix of checking FP function attributes,
IR-level FMF, and just wrong assumptions.

I am trying to avoid regressions while fixing this, and I think
the IR-level logic is good enough for that, but it's hard to say
for sure. This would be the 1st step in the clean-up.

The existing test that I changed to include 'fast' actually shows
a miscompile: the function only had the equivalent of nnan, but we
created new instructions that had fast (all FMF set). This is
similar to the example in https://llvm.org/PR35538

Differential Revision: https://reviews.llvm.org/D95452
2021-01-27 14:17:11 -05:00
Florian Hahn 3201274dea
[VPlan] Handle scalarized values in VPTransformState.
This patch adds plumbing to handle scalarized values directly in
VPTransformState.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D92282
2021-01-25 14:21:56 +00:00
Kazu Hirata 8857202489 [llvm] Use llvm::find (NFC) 2021-01-19 20:19:14 -08:00
Florian Hahn eb0371e403 [VPlan] Unify value/recipe printing after VPDef transition.
This patch unifies the way recipes and VPValues are printed after the
transition to VPDef.

VPSlotTracker has been updated to iterate over all recipes and all
their defined values to number those. There is no need to number
values in Value2VPValue.

It also updates a few places that only used slot numbers for
VPInstruction. All recipes now can produce numbered VPValues.
2021-01-11 14:42:46 +00:00
Florian Hahn 65f578fc0e [VPlan] Keep start value of VPWidenPHIRecipe as VPValue.
Similar to D92129, update VPWidenPHIRecipe  to manage the start value as
VPValue. This allows adjusting the start value as a VPlan transform,
which will be used in a follow-up patch to support reductions during
epilogue vectorization.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D93975
2021-01-09 16:34:15 +00:00
Florian Hahn c493e9216b [VPlan] Move reduction start value creation to widenPHIRecipe.
This was suggested to prepare for D93975.

By moving the start value creation to widenPHInstruction, we set the
stage to manage the start value directly in VPWidenPHIRecipe, which be
used subsequently to set the 'resume' value for reductions during
epilogue vectorization.

It also moves RdxDesc to the recipe, so we do not have to rely on Legal
to look it up later.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D94175
2021-01-08 17:49:43 +00:00
David Green 72fb5ba079 [LV] Don't sink into replication regions
The new test case here contains a first order recurrences and an
instruction that is replicated. The first order recurrence forces an
instruction to be sunk _into_, as opposed to after the replication
region. That causes several things to go wrong including registering
vector instructions multiple times and failing to create dominance
relations correctly.

Instead we should be sinking to after the replication region, which is
what this patch makes sure happens.

Differential Revision: https://reviews.llvm.org/D93629
2021-01-08 09:50:10 +00:00
Florian Hahn 816dba48af
[VPlan] Keep start value in VPWidenIntOrFpInductionRecipe (NFC).
This patch updates VPWidenIntOrFpInductionRecipe to hold the start value
for the induction variable. This makes the start value explicit and
allows for adjusting the start value for a VPlan.

The flexibility will be used in further patches.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D92129
2021-01-06 11:47:33 +00:00
Florian Hahn f73c09caa2
[VPlan] Use public VPValue constructor in VPPRedInstPHIRecipe (NFC).
VPPredInstPHIRecipe does not need access to VPValue via friendship. It
can just use the public constructor,

Discussed as part of D92281.
2021-01-06 10:47:09 +00:00
Kazu Hirata 789d250613 [CodeGen, Transforms] Use *Map::lookup (NFC) 2020-12-27 09:57:27 -08:00
Florian Hahn c0c0ae16c3
[VPlan] Make VPInstruction a VPDef
This patch turns updates VPInstruction to manage the value it defines
using VPDef. The VPValue is used  during VPlan construction and
codegeneration instead of the plain IR reference where possible.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90565
2020-12-22 09:53:47 +00:00
Florian Hahn f250892373
[VPlan] Make VPRecipeBase inherit from VPDef.
This patch makes VPRecipeBase a direct subclass of VPDef, moving the
SubclassID to VPDef.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90564
2020-12-21 13:34:00 +00:00
Florian Hahn cd608dc8d3
[VPlan] Use VPDef for VPInterleaveRecipe.
This patch turns updates VPInterleaveRecipe to manage the values it defines
using VPDef. The VPValue is used  during VPlan construction and
codegeneration instead of the plain IR reference where possible.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90562
2020-12-21 10:56:53 +00:00
Florian Hahn 7186a3965a
[VPlan] Use VPDef for VPWidenSelectRecipe.
This patch turns updates VPWidenSelectRecipe to manage the value
it defines using VPDef.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90560
2020-12-15 14:15:01 +00:00
Florian Hahn 318f5798d8
[VPlan] Use VPDef for VPWidenGEPRecipe.
This patch turns updates VPWidenGEPRecipe to manage the value it defines
using VPDef. The VPValue is used  during VPlan construction and
codegeneration instead of the plain IR reference where possible.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90561
2020-12-15 09:30:14 +00:00
Florian Hahn ad1161f9b5
[VPlan] Use VPdef for VPWidenCall.
This patch turns updates VPWidenREcipe to manage the value it defines
using VPDef.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90559
2020-12-15 09:20:07 +00:00
Florian Hahn e42e5263bd
[VPlan] Make VPWidenMemoryInstructionRecipe a VPDef.
This patch updates VPWidenMemoryInstructionRecipe to use VPDef
to manage the value it produces instead of inheriting from VPValue.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D90563
2020-12-14 14:13:59 +00:00
Sander de Smalen d568cff696 [LoopVectorizer][SVE] Vectorize a simple loop with with a scalable VF.
* Steps are scaled by `vscale`, a runtime value.
* Changes to circumvent the cost-model for now (temporary)
  so that the cost-model can be implemented separately.

This can vectorize the following loop [1]:

   void loop(int N, double *a, double *b) {
     #pragma clang loop vectorize_width(4, scalable)
     for (int i = 0; i < N; i++) {
       a[i] = b[i] + 1.0;
     }
   }

[1] This source-level example is based on the pragma proposed
separately in D89031. This patch only implements the LLVM part.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D91077
2020-12-09 11:25:21 +00:00
Florian Hahn fe83adb05a
[VPlan] Use VPUser to manage VPPredInstPHIRecipe operand (NFC).
VPPredInstPHIRecipe is one of the recipes that was missed during the
initial conversion. This patch adjusts the recipe to also manage its
operand using VPUser.
2020-11-30 13:09:58 +00:00
Florian Hahn a813090072
[VPlan] Manage stored values of interleave groups using VPUser (NFC)
Interleave groups also depend on the values they store. Manage the
stored values as VPUser operands. This is currently a NFC, but is
required to allow VPlan transforms and to manage generated vector values
exclusively in VPTransformState.
2020-11-29 17:24:36 +00:00
Florian Hahn bd0b1311db
[VPlan] Turn VPReplicateRecipe into a VPValue.
Update VPReplicateRecipe to inherit from VPValue. This still does not
update scalarizeInstruction to set the result for the VPValue of
VPReplicateRecipe, because this first requires tracking scalar values in
VPTransformState.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D91500
2020-11-26 13:50:24 +00:00
Florian Hahn ad5b83ddcf
[VPlan] Add VPReductionSC to VPUser::classof, unify VPValue IDs.
This is a follow-up to 00a6601136 to make
isa<VPReductionRecipe> work and unifies the VPValue ID names, by making
sure they all consistently start with VPV*.
2020-11-25 11:08:25 +00:00
David Green e0c479cd0e [VPlan] Switch VPWidenRecipe to be a VPValue
Similar to other patches, this makes VPWidenRecipe a VPValue. Because of
the way it interacts with the reduction code it also slightly alters the
way that VPValues are registered, removing the up front NeedDef and
using getOrAddVPValue to create them on-demand if needed instead.

Differential Revision: https://reviews.llvm.org/D88447
2020-11-25 08:25:06 +00:00
David Green 00a6601136 [VPlan] Turn VPReductionRecipe into a VPValue
This converts the VPReductionRecipe into a VPValue, like other
VPRecipe's in preparation for traversing def-use chains. It also makes
it a VPUser, now storing the used VPValues as operands.

It doesn't yet change how the VPReductionRecipes are created. It will
need to call replaceAllUsesWith from the original recipe they replace,
but that is not done yet as VPWidenRecipe need to be created first.

Differential Revision: https://reviews.llvm.org/D88382
2020-11-25 08:25:05 +00:00
Florian Hahn 0c119ba8a8 [VPlan] Use VPValue def for VPWidenGEPRecipe.
This patch turns VPWidenGEPRecipe into a VPValue and uses it
during VPlan construction and codegeneration instead of the plain IR
reference where possible.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D84683
2020-11-15 15:12:47 +00:00
Florian Hahn a70b511e78 Recommit "[VPlan] Use VPValue def for VPWidenSelectRecipe."
This reverts the revert commit c8d73d939f.

It includes a fix for cases where we missed inserting VPValues
for some selects, which should fix PR48142.
2020-11-14 20:00:25 +00:00
Florian Hahn c8d73d939f Revert "[VPlan] Use VPValue def for VPWidenSelectRecipe."
This reverts commit a8e50f1c6e.

This reportedly breaks building the Linux kernel.
  https://bugs.llvm.org/show_bug.cgi?id=48142
2020-11-10 22:50:46 +00:00
Florian Hahn a8e50f1c6e
[VPlan] Use VPValue def for VPWidenSelectRecipe.
This patch turns VPWidenSelectRecipe into a VPValue and uses it
during VPlan construction and codegeneration instead of the plain IR
reference where possible.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D84682
2020-11-10 19:39:37 +00:00
Florian Hahn 537829f2a7
[VPlan] Add isStore helper to VPWidenMemoryInstructionRecipe (NFC).
Move logic to check if the recipe is a store to a helper for easier
reuse.
2020-11-09 14:01:29 +00:00
Florian Hahn fec64de261
[VPlan] Use VPValue def for VPWidenCall.
This patch turns VPWidenCall into a VPValue and uses it
during VPlan construction and codegeneration instead of the plain IR
reference where possible.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D84681
2020-11-09 13:29:41 +00:00
Sander de Smalen 4a3bb9ea6c [VPlan] NFC: Change VFRange to take ElementCount
This patch changes the type of Start, End in VFRange to be an ElementCount
instead of `unsigned`. This is done as preparation to make VPlans for
scalable vectors, but is otherwise NFC.

Reviewed By: dmgreen, fhahn, vkmr

Differential Revision: https://reviews.llvm.org/D90715
2020-11-06 09:50:20 +00:00
Florian Hahn 93f6c6b79c Recommit "[VPlan] Use VPValue def for VPMemoryInstructionRecipe."
This reverts the revert commit 710aceb645
and includes a fix for a memsan failure.

Original message:

    This patch turns VPMemoryInstructionRecipe into a VPValue and uses it
    during VPlan construction and codegeneration instead of the plain IR
    reference where possible.
2020-10-14 17:41:23 +01:00
Vitaly Buka 710aceb645 Revert "[VPlan] Use VPValue def for VPMemoryInstructionRecipe."
It introduced a memory leak.

This reverts commit 525b085a65.
2020-10-13 03:14:08 -07:00
Florian Hahn 525b085a65 [VPlan] Use VPValue def for VPMemoryInstructionRecipe.
This patch turns VPMemoryInstructionRecipe into a VPValue and uses it
during VPlan construction and codegeneration instead of the plain IR
reference where possible.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D84680
2020-10-12 18:02:33 +01:00
Florian Hahn ea058d289c [VPlan] Use operands for printing of VPWidenMemoryInstructionRecipe.
Now that operands of the recipe are managed through VPUser, we can
simplify the printing by just using the operands.
2020-10-12 16:51:54 +01:00
David Green be6e8e50f4 [LV] Tail folded inloop reductions.
This expands upon the inloop reductions added in e9761688e41cb9e976,
allowing them to be inserted into tail folded loops. Reductions are
generates with the form:

  x = select(mask, vecop, zero)
  v = vecreduce.add(x)
  c = add chain, v

Where zero here is chosen as the identity value for add reductions. The
backend is then expected to fold the select and the vecreduce into a
single predicated instruction.

Most of the code is fairly straight forward, except for the creation of
blockmasks which need to ensure they are created in dominance order. The
order they are added is altered to be after any phis, keeping the
requirements for the underlying IR.

Differential Revision: https://reviews.llvm.org/D84451
2020-10-11 16:58:34 +01:00
Florian Hahn 348d85a6c7 [VPlan] Clean up uses/operands on VPBB deletion.
Update the code responsible for deleting VPBBs and recipes to properly
update users and release operands.

This is another preparation for D84680 & following patches towards
enabling modeling def-use chains in VPlan.
2020-10-05 14:43:52 +01:00
Florian Hahn 357bbaab66 [VPlan] Add VPRecipeBase::toVPUser helper (NFC).
This adds a helper to convert a VPRecipeBase pointer to a VPUser, for
recipes that inherit from VPUser. Once VPRecipeBase directly inherits
from VPUser this helper can be removed.
2020-10-04 19:43:27 +01:00
Florian Hahn d856365470 [VPlan] Change recipes to inherit from VPUser instead of a member var.
Now that VPUser is not inheriting from VPValue, we can take the next
step and turn the recipes that already manage their operands via VPUser
into VPUsers directly. This is another small step towards traversing
def-use chains in VPlan.

This is NFC with respect to the generated code, but makes the interface
more powerful.
2020-09-30 14:39:00 +01:00
Florian Hahn 31923f6b36 [VPlan] Disconnect VPValue and VPUser.
This refactors VPuser to not inherit from VPValue to facilitate
introducing operations that introduce multiple VPValues (e.g.
VPInterleaveRecipe).

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D84679
2020-09-23 14:44:31 +01:00
Florian Hahn c671e34bf2 [VPlan] Add dump() helper to VPValue & VPRecipeBase.
This provides a convenient way to print VPValues and recipes in a
debugger. In particular it saves the user from instantiating
VPSlotTracker to print recipes or values.
2020-09-22 15:55:16 +01:00
Simon Pilgrim 5ea9e655ef VPlan.h - remove unnecessary forward declarations. NFCI.
Already defined in includes.
2020-09-07 18:35:06 +01:00
David Sherwood f4257c5832 [SVE] Make ElementCount members private
This patch changes ElementCount so that the Min and Scalable
members are now private and can only be accessed via the get
functions getKnownMinValue() and isScalable(). In addition I've
added some other member functions for more commonly used operations.
Hopefully this makes the class more useful and will reduce the
need for calling getKnownMinValue().

Differential Revision: https://reviews.llvm.org/D86065
2020-08-28 14:43:53 +01:00
Francesco Petrogalli 5a34b3ab95 [llvm][LV] Replace `unsigned VF` with `ElementCount VF` [NFCI]
Changes:

* Change `ToVectorTy` to deal directly with `ElementCount` instances.
* `VF == 1` replaced with `VF.isScalar()`.
* `VF > 1` and `VF >=2` replaced with `VF.isVector()`.
* `VF <=1` is replaced with `VF.isZero() || VF.isScalar()`.
* Replaced the uses of `llvm::SmallSet<ElementCount, ...>` with
   `llvm::SmallSetVector<ElementCount, ...>`. This avoids the need of an
   ordering function for the `ElementCount` class.
* Bits and pieces around printing the `ElementCount` to string streams.

To guarantee that this change is a NFC, `VF.Min` and asserts are used
in the following places:

1. When it doesn't make sense to deal with the scalable property, for
example:
   a. When computing unrolling factors.
   b. When shuffle masks are built for fixed width vector types
In this cases, an
assert(!VF.Scalable && "<mgs>") has been added to make sure we don't
enter coepaths that don't make sense for scalable vectors.
2. When there is a conscious decision to use `FixedVectorType`. These
uses of `FixedVectorType` will likely be removed in favour of
`VectorType` once the vectorizer is generic enough to deal with both
fixed vector types and scalable vector types.
3. When dealing with building constants out of the value of VF, for
example when computing the vectorization `step`, or building vectors
of indices. These operation _make sense_ for scalable vectors too,
but changing the code in these places to be generic and make it work
for scalable vectors is to be submitted in a separate patch, as it is
a functional change.
4. When building the potential VFs in VPlan. Making the VPlan generic
enough to handle scalable vectorization factors is a functional change
that needs a separate patch. See for example `void
LoopVectorizationPlanner::buildVPlans(unsigned MinVF, unsigned
MaxVF)`.
5. The class `IntrinsicCostAttribute`: this class still uses `unsigned
VF` as updating the field to use `ElementCount` woudl require changes
that could result in changing the behavior of the compiler. Will be done
in a separate patch.
7. When dealing with user input for forcing the vectorization
factor. In this case, adding support for scalable vectorization is a
functional change that migh require changes at command line.

Note that in some places the idiom

```
unsigned VF = ...
auto VTy = FixedVectorType::get(ScalarTy, VF)
```

has been replaced with

```
ElementCount VF = ...
assert(!VF.Scalable && ...);
auto VTy = VectorType::get(ScalarTy, VF)
```

The assertion guarantees that the new code is (at least in debug mode)
functionally equivalent to the old version. Notice that this change had been
possible because none of the methods that are specific to `FixedVectorType`
were used after the instantiation of `VTy`.

Reviewed By: rengolin, ctetreau

Differential Revision: https://reviews.llvm.org/D85794
2020-08-24 13:54:03 +00:00
Francesco Petrogalli bad7d6b373 Revert "[llvm][LV] Replace `unsigned VF` with `ElementCount VF` [NFCI]"
Reverting because the commit message doesn't reflect the one agreed on
phabricator at https://reviews.llvm.org/D85794.

This reverts commit c8d2b065b9.
2020-08-24 13:50:55 +00:00
Francesco Petrogalli c8d2b065b9 [llvm][LV] Replace `unsigned VF` with `ElementCount VF` [NFCI]
Changes:

* Change `ToVectorTy` to deal directly with `ElementCount` instances.
* `VF == 1` replaced with `VF.isScalar()`.
* `VF > 1` and `VF >=2` replaced with `VF.isVector()`.
* `VF <=1` is replaced with `VF.isZero() || VF.isScalar()`.
* Add `<` operator to `ElementCount` to be able to use
`llvm::SmallSetVector<ElementCount, ...>`.
* Bits and pieces around printing the ElementCount to string streams.
* Added a static method to `ElementCount` to represent a scalar.

To guarantee that this change is a NFC, `VF.Min` and asserts are used
in the following places:

1. When it doesn't make sense to deal with the scalable property, for
example:
   a. When computing unrolling factors.
   b. When shuffle masks are built for fixed width vector types
In this cases, an
assert(!VF.Scalable && "<mgs>") has been added to make sure we don't
enter coepaths that don't make sense for scalable vectors.
2. When there is a conscious decision to use `FixedVectorType`. These
uses of `FixedVectorType` will likely be removed in favour of
`VectorType` once the vectorizer is generic enough to deal with both
fixed vector types and scalable vector types.
3. When dealing with building constants out of the value of VF, for
example when computing the vectorization `step`, or building vectors
of indices. These operation _make sense_ for scalable vectors too,
but changing the code in these places to be generic and make it work
for scalable vectors is to be submitted in a separate patch, as it is
a functional change.
4. When building the potential VFs in VPlan. Making the VPlan generic
enough to handle scalable vectorization factors is a functional change
that needs a separate patch. See for example `void
LoopVectorizationPlanner::buildVPlans(unsigned MinVF, unsigned
MaxVF)`.
5. The class `IntrinsicCostAttribute`: this class still uses `unsigned
VF` as updating the field to use `ElementCount` woudl require changes
that could result in changing the behavior of the compiler. Will be done
in a separate patch.
7. When dealing with user input for forcing the vectorization
factor. In this case, adding support for scalable vectorization is a
functional change that migh require changes at command line.

Differential Revision: https://reviews.llvm.org/D85794
2020-08-24 13:39:42 +00:00
David Green 745bf6cf44 [LoopVectorizer] Inloop vector reductions
Arm MVE has multiple instructions such as VMLAVA.s8, which (in this
case) can take two 128bit vectors, sign extend the inputs to i32,
multiplying them together and sum the result into a 32bit general
purpose register. So taking 16 i8's as inputs, they can multiply and
accumulate the result into a single i32 without any rounding/truncating
along the way. There are also reduction instructions for plain integer
add and min/max, and operations that sum into a pair of 32bit registers
together treated as a 64bit integer (even though MVE does not have a
plain 64bit addition instruction). So giving the vectorizer the ability
to use these instructions both enables us to vectorize at higher
bitwidths, and to vectorize things we previously could not.

In order to do that we need a way to represent that the reduction
operation, specified with a llvm.experimental.vector.reduce when
vectorizing for Arm, occurs inside the loop not after it like most
reductions. This patch attempts to do that, teaching the vectorizer
about in-loop reductions. It does this through a vplan recipe
representing the reductions that the original chain of reduction
operations is replaced by. Cost modelling is currently just done through
a prefersInloopReduction TTI hook (which follows in a later patch).

Differential Revision: https://reviews.llvm.org/D75069
2020-08-06 10:10:50 +01:00
Jordan Rupprecht 3c39db0c44 Revert "[LoopVectorizer] Inloop vector reductions"
This reverts commit e9761688e4. It breaks the build:

```
~/src/llvm-project/llvm/lib/Analysis/IVDescriptors.cpp:868:10: error: no viable conversion from returned value of type 'SmallVector<[...], 8>' to function return type 'SmallVector<[...], 4>'
  return ReductionOperations;
```
2020-08-05 10:24:15 -07:00
David Green e9761688e4 [LoopVectorizer] Inloop vector reductions
Arm MVE has multiple instructions such as VMLAVA.s8, which (in this
case) can take two 128bit vectors, sign extend the inputs to i32,
multiplying them together and sum the result into a 32bit general
purpose register. So taking 16 i8's as inputs, they can multiply and
accumulate the result into a single i32 without any rounding/truncating
along the way. There are also reduction instructions for plain integer
add and min/max, and operations that sum into a pair of 32bit registers
together treated as a 64bit integer (even though MVE does not have a
plain 64bit addition instruction). So giving the vectorizer the ability
to use these instructions both enables us to vectorize at higher
bitwidths, and to vectorize things we previously could not.

In order to do that we need a way to represent that the reduction
operation, specified with a llvm.experimental.vector.reduce when
vectorizing for Arm, occurs inside the loop not after it like most
reductions. This patch attempts to do that, teaching the vectorizer
about in-loop reductions. It does this through a vplan recipe
representing the reductions that the original chain of reduction
operations is replaced by. Cost modelling is currently just done through
a prefersInloopReduction TTI hook (which follows in a later patch).

Differential Revision: https://reviews.llvm.org/D75069
2020-08-05 18:14:05 +01:00
Florian Hahn c0cdba727a [VPlan] Add & use VPValue for VPWidenGEPRecipe operands (NFC).
This patch adds VPValue version of the GEP's operands to
VPWidenGEPRecipe and uses them during code-generation.

Reviewers: Ayal, gilr, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D80220
2020-06-26 20:59:17 +01:00
Sjoerd Meijer e345d547a0 Recommit "[LV] Emit @llvm.get.active.lane.mask for tail-folded loops"
Fixed ARM regression test.

Please see the original commit message rG47650451738c for details.
2020-06-17 13:12:15 +01:00
Sjoerd Meijer d4e183f686 Revert "[LV] Emit @llvm.get.active.mask for tail-folded loops"
This reverts commit 4765045173
while I investigate the build bot failures.
2020-06-17 10:09:54 +01:00
Sjoerd Meijer 4765045173 [LV] Emit @llvm.get.active.mask for tail-folded loops
This emits new IR intrinsic @llvm.get.active.mask for tail-folded vectorised
loops if the intrinsic is supported by the backend, which is checked by
querying TargetTransform hook emitGetActiveLaneMask.

This intrinsic creates a mask representing active and inactive vector lanes,
which is used by the masked load/store instructions that are created for
tail-folded loops. The semantics of @llvm.get.active.mask are described here in
LangRef:

https://llvm.org/docs/LangRef.html#llvm-get-active-lane-mask-intrinsics

This intrinsic is also used to provide a hint to the backend. That is, the
second argument of the intrinsic represents the back-edge taken count of the
loop. For MVE, for example, we use that to set up tail-predication, which is a
new form of predication in MVE for vector loops that implicitely predicates the
last vector loop iteration by implicitely setting active/inactive lanes, i.e.
the tail loop is predicated. In order to set up a tail-predicated vector loop,
we need to know the number of data elements processed by the vector loop, which
corresponds the the tripcount of the scalar loop, which we can now reconstruct
using @llvm.get.active.mask.

Differential Revision: https://reviews.llvm.org/D79100
2020-06-17 09:53:58 +01:00
Florian Hahn 211596c94e [VPlan] Support extracting lanes for defs managed in VPTransformState.
Currently extracting a lane for a VPValue def is not supported, if it is
managed directly by VPTransformState (e.g. because it is created by a
VPInstruction or an external VPValue def).

For now, simply extract the requested lane. In the future, we should
also cache the extracted scalar values, similar to LV.

Reviewers: Ayal, rengolin, gilr, SjoerdMeijer

Reviewed By: SjoerdMeijer

Differential Revision: https://reviews.llvm.org/D80787
2020-06-03 12:14:16 +01:00
Florian Hahn 15224408f0 [VPlan] Use VPUser for VPWidenSelectRecipe operands (NFC).
VPWidenSelectRecipe already contains a VPUser, but it is not used. This
patch updates the code related to VPWidenSelectRecipe to use VPUser for
its operands.

Reviewers: Ayal, gilr, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D80219
2020-05-24 13:58:08 +01:00
Florian Hahn cff9399f6b [VPlan] Fix comment for User in VPWidenSelectRecipe (NFC).
The comment was referring the arguments of the call, but the recipe
widens a select.
2020-05-19 15:31:39 +01:00
Florian Hahn f828d75b46 [VPlan] Add & use VPValue operands for VPReplicateRecipe (NFC).
This patch adds VPValue version of the instruction operands to
VPReplicateRecipe and uses them during code-generation.

Reviewers: Ayal, gilr, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D80114
2020-05-19 15:12:17 +01:00
Florian Hahn 66ad107452 [VPlan] Remove unique_ptr from VPBranchOnRecipeMask (NFC).
We can remove a dynamic memory allocation, by checking the number of
operands: no operands = all true, 1 operand = mask.

Reviewers: Ayal, gilr, rengolin

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D80110
2020-05-19 15:01:37 +01:00
Florian Hahn bbdfcf8f69 [VPlan] Remove unused & undefined print method (NFC). 2020-05-03 18:36:20 +01:00
Florian Hahn e89379856a Recommit "[VPlan] Add & use VPValue operands for VPWidenRecipe (NFC)."
The crash that caused the original revert has been fixed in
a3c964a278. I also added a reduced version of the crash reproducer.

This reverts the revert commit 2107af9ccf.
2020-04-29 11:40:39 +01:00
Ayal Zaks a3c964a278 [LV] Fix recording of BranchTakenCount for FoldTail
When folding tail, branch taken count is computed during initial VPlan execution
and recorded to be used by the compare computing the loop's mask. This recording
should directly set the State, instead of reusing Value2VPValue mapping which
serves original Values present prior to vectorization.
The branch taken count may be a constant Value, which may be used elsewhere in
the loop; trying to employ Value2VPValue for both leads to the issue reported in
https://reviews.llvm.org/D76992#inline-721028

Differential Revision: https://reviews.llvm.org/D78847
2020-04-26 20:13:10 +03:00
Mehdi Amini 2107af9ccf Revert "[VPlan] Add & use VPValue operands for VPWidenRecipe (NFC)."
This reverts commit 9245c7ac13.

This is triggering a segfault in XLA downstream, we'll follow-up with
a reproducer, it is likely influenced by TTI/TLI settings or other
options as a simple `opt -loop-vectorize` invocation on the IR
before the crash does not reproduce immediately.
2020-04-24 05:07:32 +00:00
Simon Pilgrim b108a457e1 [VPlan] Remove unused forward declarations. NFC.
Move VPlan.h include from VPlanVerifier.h down to VPlanVerifier.cpp
2020-04-23 12:34:20 +01:00
Florian Hahn 9245c7ac13 [VPlan] Add & use VPValue operands for VPWidenRecipe (NFC).
This patch adds VPValue version of the instruction operands to
VPWidenRecipe and uses them during code-generation.

Similar to D76373 this reduces ingredient def-use usage by ILV as
a step towards full VPlan-based def-use relations.

Reviewers: rengolin, Ayal, gilr

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D76992
2020-04-23 12:16:46 +01:00
Gil Rapaport b747d72c19 [LV] Fix PR45525: Incorrect assert in blend recipe
Fix an assert introduced in 41ed5d856c1: a phi with a single predecessor and a
mask is a valid case which is already supported by the code.

Differential Revision: https://reviews.llvm.org/D78115
2020-04-15 10:39:07 +03:00
Florian Hahn 18138e0252 [VPlan] Introduce VPWidenSelectRecipe (NFC).
Widening a selects depends on whether the condition is loop invariant or
not. Rather than checking during codegen-time, the information can be
recorded at the VPlan construction time.

This was suggested as part of D76992, to reduce the reliance on
accessing the original underlying IR values.

Reviewers: gilr, rengolin, Ayal, hsaito

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D77869
2020-04-13 08:35:28 +01:00
Florian Hahn 719846c469 [VPlan] Drop redundant private: at beginning of class defs (NFC).
Default visibility for classes is private, so the private: at the top of
various class definitions is redundant.

Reviewers: gilr, rengolin, Ayal, hsaito

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D77810
2020-04-11 13:27:10 +01:00
Gil Rapaport e2a1867880 [LV] Add VPValue operands to VPBlendRecipe (NFCI)
InnerLoopVectorizer's code called during VPlan execution still relies on
original IR's def-use relations to decide which vector code to generate,
limiting VPlan transformations ability to modify def-use relations and still
have ILV generate the vector code.
This commit introduces VPValues for VPBlendRecipe to use as the values to
blend. The recipe is generated with VPValues wrapping the phi's incoming values
of the scalar phi. This reduces ingredient def-use usage by ILV as a step
towards full VPlan-based def-use relations.

Differential Revision: https://reviews.llvm.org/D77539
2020-04-09 18:48:33 +03:00
Ayal Zaks 1678489234 [LV] FoldTail w/o Primary Induction
Introduce a new VPWidenCanonicalIVRecipe to generate a canonical vector
induction for use in fold-tail-with-masking, if a primary induction is absent.

The canonical scalar IV having start = 0 and step = VF*UF, created during code
-gen to control the vector loop, is widened into a canonical vector IV having
start = {<Part*VF, Part*VF+1, ..., Part*VF+VF-1> for 0 <= Part < UF} and
step = <VF*UF, VF*UF, ..., VF*UF>.

Differential Revision: https://reviews.llvm.org/D77635
2020-04-09 17:45:23 +03:00
Florian Hahn 9997ee23ed [VPlan] Add & use VPValue operands for VPWidenCallRecipe (NFC).
This patch adds VPValue versions for the arguments of the call to
VPWidenCallRecipe and uses them during code-generation.

Similar to D76373 this reduces ingredient def-use usage by ILV as
a step towards full VPlan-based def-use relations.

Reviewers: Ayal, gilr, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D77655
2020-04-09 10:23:26 +01:00
Florian Hahn 90be3c24a7 [VPlan] Introduce new VPWidenCallRecipe (NFC).
This patch moves calls to their own recipe, to simplify the transition
to VPUser for operands of VPWidenRecipe, as discussed in D76992.

Subsequently additional information can be added to the recipe rather
than computing it during the execute step.

Reviewers: rengolin, Ayal, gilr, hsaito

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D77467
2020-04-06 16:07:37 +01:00
Florian Hahn 49d00824bb [VPlan] Use one VPWidenRecipe per original IR instruction. (NFC).
This patch changes VPWidenRecipe to only store a single original IR
instruction. This is the first required step towards modeling it's
operands as VPValues and also towards breaking it up into a
VPInstruction.

Discussed as part of D74695.

Reviewers: Ayal, gilr, rengolin

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D76988
2020-03-29 13:47:28 +01:00
Gil Rapaport 078c863305 [LV] Replace stored value with a VPValue (NFCI)
InnerLoopVectorizer's code called during VPlan execution still relies on
original IR's def-use relations to decide which vector code to generate,
limiting VPlan transformations ability to modify def-use relations and still
have ILV generate the vector code.
This commit introduces a VPValue for VPWidenMemoryInstructionRecipe to use as
the stored value. The recipe is generated with a VPValue wrapping the stored
value of the scalar store. This reduces ingredient def-use usage by ILV as a
step towards full VPlan-based def-use relations.

Differential Revision: https://reviews.llvm.org/D76373
2020-03-25 19:36:55 +02:00
Florian Hahn 00c1cd1934 [VPlan] Record underlying value for VPValues created by addVPValue (NFC).
Now that printing VPValues uses the underlying IR value name, if
available, recording the underlying value here improves printing.

Reviewers: rengolin, hsaito, Ayal, gilr

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D76374
2020-03-18 21:30:58 +00:00
Florian Hahn e6a74803d4 [VPlan] Use underlying value for printing, if available.
When the an underlying value is available, we can use its name for
printing, as discussed in D73078.

Reviewers: rengolin, hsaito, Ayal, gilr

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D76200
2020-03-18 17:46:57 +00:00
Florian Hahn 40e7bfc424 [VPlan] Use consecutive numbers to print VPValues instead of addresses.
Currently when printing VPValues we use the object address, which makes
it hard to distinguish VPValues as they usually are large numbers with
varying distance between them.

This patch adds a simple slot tracker, similar to the ModuleSlotTracker
used for IR values. In order to dump a VPValue or anything containing a
VPValue, a slot tracker for the enclosing VPlan needs to be created. The
existing VPlanPrinter can take care of that for the existing code. We
assign consecutive numbers to each VPValue we encounter in a reverse
post order traversal of the VPlan.

Reviewers: rengolin, hsaito, fhahn, Ayal, dorit, gilr

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D73078
2020-03-05 14:55:15 +00:00
Florian Hahn 05afa55521 [VPlan] Add getPlan() to VPBlockBase.
This patch adds a getPlan accessor to VPBlockBase, which finds the entry
block of the plan containing the block and returns the plan set for this
block.

VPBlockBase contains a VPlan pointer, but it should only be set for
the entry block of a plan. This allows moving blocks without updating
the pointer for each moved block and in the future we might introduce a
parent relationship between plans and blocks, similar to the one in LLVM IR.

Reviewers: rengolin, hsaito, fhahn, Ayal, dorit, gilr

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D74445
2020-03-03 13:20:13 +00:00
Gil Rapaport 8647a72c4a [LV] VPValues for memory operation pointers (NFCI)
Memory instruction widening recipes use the pointer operand of their load/store
ingredient for generating the needed GEPs, making it difficult to feed these
recipes with pointers based on other ingredients or none at all.
This patch modifies these recipes to use a VPValue for the pointer instead, in
order to reduce ingredient def-use usage by ILV as a step towards full
VPlan-based def-use relations. The recipes are constructed with VPValues bound
to these ingredients, maintaining current behavior.

Differential revision: https://reviews.llvm.org/D70865
2020-01-10 09:24:59 +02:00
Evgeniy Brevnov 948e745270 [LV][NFC] Keep dominator tree up to date during vectorization. 2019-12-30 18:38:41 +07:00