optsize using masked wide loads
Under Opt for Size, the vectorizer does not vectorize interleave-groups that
have gaps at the end of the group (such as a loop that reads only the even
elements: a[2*i]) because that implies that we'll require a scalar epilogue
(which is not allowed under Opt for Size). This patch extends the support for
masked-interleave-groups (introduced by D53011 for conditional accesses) to
also cover the case of gaps in a group of loads; Targets that enable the
masked-interleave-group feature don't have to invalidate interleave-groups of
loads with gaps; they could now use masked wide-loads and shuffles (if that's
what the cost model selects).
Reviewers: Ayal, hsaito, dcaballe, fhahn
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D53668
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Correct costings of SK_ExtractSubvector requires the SubTy argument to indicate the type/size of the extracted subvector.
Unlike the rest of the shuffle kinds this means that the main Ty argument represents the source vector type not the destination!
I've done my best to fix a number of vectorizer uses:
SLP - the reduction epilogue costs should be using a SK_PermuteSingleSrc shuffle as these all occur at the hardware vector width - we're not extracting (illegal) subvector types. This is causing the cost model diffs as SK_ExtractSubvector costs are poorly handled and tend to just return 1 at the moment.
LV - I'm not clear on what the SK_ExtractSubvector should represents for recurrences - I've used a <1 x ?> subvector extraction as that seems to match the VF delta.
Differential Revision: https://reviews.llvm.org/D53573
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This commit is a combination of two patches:
* "Fix in getScalarizationOverhead()"
If target returns false in TTI.prefersVectorizedAddressing(), it means the
address registers will not need to be extracted. Therefore, there should
be no operands scalarization overhead for a load instruction.
* "Don't pass the instruction pointer from getMemInstScalarizationCost."
Since VF is always > 1, this is a cost query for an instruction in the
vectorized loop and it should not be evaluated within the scalar
context of the instruction.
Review: Ulrich Weigand, Hal Finkel
https://reviews.llvm.org/D52351https://reviews.llvm.org/D52417
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masked-interleaving is enabled
Enable interleave-groups under fold-tail scenario for Opt for size compilation;
D50480 added support for vectorizing loops of arbitrary trip-count without a
remiander, which in turn makes everything in the loop conditional, including
interleave-groups if any. It therefore invalidated all interleave-groups
because we didn't have support for vectorizing predicated interleaved-groups
at the time. In the meantime, D53011 introduced this support, so we don't
have to invalidate interleave-groups when masked-interleaved support is enabled.
Reviewers: Ayal, hsaito, dcaballe, fhahn
Reviewed By: hsaito
Differential Revision: https://reviews.llvm.org/D53559
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optimizing for size
LV is careful to respect -Os and not to create a scalar epilog in all cases
(runtime tests, trip-counts that require a remainder loop) except for peeling
due to gaps in interleave-groups. This patch fixes that; -Os will now have us
invalidate such interleave-groups and vectorize without an epilog.
The patch also removes a related FIXME comment that is now obsolete, and was
also inaccurate:
"FIXME: return None if loop requiresScalarEpilog(<MaxVF>), or look for a smaller
MaxVF that does not require a scalar epilog."
(requiresScalarEpilog() has nothing to do with VF).
Reviewers: Ayal, hsaito, dcaballe, fhahn
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D53420
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When optimizing for size, a loop is vectorized only if the resulting vector loop
completely replaces the original scalar loop. This holds if no runtime guards
are needed, if the original trip-count TC does not overflow, and if TC is a
known constant that is a multiple of the VF. The last two TC-related conditions
can be overcome by
1. rounding the trip-count of the vector loop up from TC to a multiple of VF;
2. masking the vector body under a newly introduced "if (i <= TC-1)" condition.
The patch allows loops with arbitrary trip counts to be vectorized under -Os,
subject to the existing cost model considerations. It also applies to loops with
small trip counts (under -O2) which are currently handled as if under -Os.
The patch does not handle loops with reductions, live-outs, or w/o a primary
induction variable, and disallows interleave groups.
(Third, final and main part of -)
Differential Revision: https://reviews.llvm.org/D50480
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Summary:
Teach vectorizer about vectorizing variant value stores to uniform
address. Similar to rL343028, we do not allow vectorization if we have
multiple stores to the same uniform address.
Cost model already has the change for considering the extract
instruction cost for a variant value store. See added test cases for how
vectorization is done.
The patch also contains changes to the ORE messages.
Reviewers: Ayal, mkuper, anemet, hsaito
Subscribers: rkruppe, llvm-commits
Differential Revision: https://reviews.llvm.org/D52656
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interleave-group
The vectorizer currently does not attempt to create interleave-groups that
contain predicated loads/stores; predicated strided accesses can currently be
vectorized only using masked gather/scatter or scalarization. This patch makes
predicated loads/stores candidates for forming interleave-groups during the
Loop-Vectorizer's analysis, and adds the proper support for masked-interleave-
groups to the Loop-Vectorizer's planning and transformation stages. The patch
also extends the TTI API to allow querying the cost of masked interleave groups
(which each target can control); Targets that support masked vector loads/
stores may choose to enable this feature and allow vectorizing predicated
strided loads/stores using masked wide loads/stores and shuffles.
Reviewers: Ayal, hsaito, dcaballe, fhahn, javed.absar
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D53011
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We assign indices sequentially for seen instructions, so we can just use
a vector and push back the seen instructions. No need for using a
DenseMap.
Reviewers: hsaito, rengolin, nadav, dcaballe
Reviewed By: rengolin
Differential Revision: https://reviews.llvm.org/D53089
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We can avoid doing some unnecessary work by skipping debug instructions
in a few loops. It also helps to ensure debug instructions do not
prevent vectorization, although I do not have any concrete test cases
for that.
Reviewers: rengolin, hsaito, dcaballe, aprantl, vsk
Reviewed By: rengolin, dcaballe
Differential Revision: https://reviews.llvm.org/D53091
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At the point when we perform `emitTransformedIndex`, we have a broken IR (in
particular, we have Phis for which not every incoming value is properly set). On
such IR, it is illegal to create SCEV expressions, because their internal
simplification process may try to prove some predicates and break when it
stumbles across some broken IR.
The only purpose of using SCEV in this particular place is attempt to simplify
the generated code slightly. It seems that the result isn't worth it, because
some trivial cases (like addition of zero and multiplication by 1) can be
handled separately if needed, but more generally InstCombine is able to achieve
the goals we want to achieve by using SCEV.
This patch fixes a functional crash described in PR39160, and as side-effect it
also generates a bit smarter code in some simple cases. It also may cause some
optimality loss (i.e. we will now generate `mul` by power of `2` instead of
shift etc), but there is nothing what InstCombine could not handle later. In
case of dire need, we can support more trivial cases just in place.
Note that this patch only fixes one particular case of the general problem that
LV misuses SCEV, attempting to create SCEVs or prove predicates on invalid IR.
The general solution, however, seems complex enough.
Differential Revision: https://reviews.llvm.org/D52881
Reviewed By: fhahn, hsaito
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343954 91177308-0d34-0410-b5e6-96231b3b80d8
Call getOperandInfo() instead of using (near) duplicated code in
LoopVectorizationCostModel::getInstructionCost().
This gets the OperandValueKind and OperandValueProperties values for a Value
passed as operand to an arithmetic instruction.
getOperandInfo() used to be a static method in TargetTransformInfo.cpp, but
is now instead a public member.
Review: Florian Hahn
https://reviews.llvm.org/D52883
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Summary:
We are overly conservative in loop vectorizer with respect to stores to loop
invariant addresses.
More details in https://bugs.llvm.org/show_bug.cgi?id=38546
This is the first part of the fix where we start with vectorizing loop invariant
values to loop invariant addresses.
This also includes changes to ORE for stores to invariant address.
Reviewers: anemet, Ayal, mkuper, mssimpso
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50665
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Support for vectorizing loops with secondary floating-point induction
variables was added in r276554. A primary integer IV is still required
for vectorization to be done. If an FP IV was found, but no integer IV
was found at all (primary or secondary), the attempt to vectorize still
went forward, causing a compiler-crash. This change abandons that
attempt when no integer IV is found. (Vectorizing FP-only cases like
this, rather than bailing out, is discussed as possible future work
in D52327.)
See PR38800 for more information.
Differential Revision: https://reviews.llvm.org/D52327
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Summary:
[VPlan] Implement vector code generation support for simple outer loops.
Context: Patch Series #1 for outer loop vectorization support in LV using VPlan. (RFC: http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html).
This patch introduces vector code generation support for simple outer loops that are currently supported in the VPlanNativePath. Changes here essentially do the following:
- force vector code generation using explicit vectorize_width
- add conservative early returns in cost model and other places for VPlanNativePath
- add code for setting up outer loop inductions
- support for widening non-induction PHIs that can result from inner loops and uniform conditional branches
- support for generating uniform inner branches
We plan to add a handful C outer loop executable tests once the initial code generation support is committed. This patch is expected to be NFC for the inner loop vectorizer path. Since we are moving in the direction of supporting outer loop vectorization in LV, it may also be time to rename classes such as InnerLoopVectorizer.
Reviewers: fhahn, rengolin, hsaito, dcaballe, mkuper, hfinkel, Ayal
Reviewed By: fhahn, hsaito
Subscribers: dmgreen, bollu, tschuett, rkruppe, rogfer01, llvm-commits
Differential Revision: https://reviews.llvm.org/D50820
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342197 91177308-0d34-0410-b5e6-96231b3b80d8
Move the 2 classes out of LoopVectorize.cpp to make it easier to re-use
them for VPlan outside LoopVectorize.cpp
Reviewers: Ayal, mssimpso, rengolin, dcaballe, mkuper, hsaito, hfinkel, xbolva00
Reviewed By: rengolin, xbolva00
Differential Revision: https://reviews.llvm.org/D49488
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Summary:
Move InductionDescriptor::transform() routine from LoopUtils to its only uses in LoopVectorize.cpp.
Specifically, the function is renamed as InnerLoopVectorizer::emitTransformedIndex().
This is a child to D51153.
Reviewers: dmgreen, llvm-commits
Reviewed By: dmgreen
Differential Revision: https://reviews.llvm.org/D51837
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Fix a latent bug in loop vectorizer which generates incorrect code for
memory accesses that are executed conditionally. As pointed in review,
this bug definitely affects uniform loads and may affect conditional
stores that should have turned into scatters as well).
The code gen for conditionally executed uniform loads on architectures
that support masked gather instructions is broken.
Without this patch, we were unconditionally executing the *conditional*
load in the vectorized version.
This patch does the following:
1. Uniform conditional loads on architectures with gather support will
have correct code generated. In particular, the cost model
(setCostBasedWideningDecision) is fixed.
2. For the recipes which are handled after the widening decision is set,
we use the isScalarWithPredication(I, VF) form which is added in the
patch.
3. Fix the vectorization cost model for scalarization
(getMemInstScalarizationCost): implement and use isPredicatedInst to
identify *all* predicated instructions, not just scalar+predicated. So,
now the cost for scalarization will be increased for maskedloads/stores
and gather/scatter operations. In short, we should be choosing the
gather/scatter in place of scalarization on archs where it is
profitable.
4. We needed to weaken the assert in useEmulatedMaskMemRefHack.
Reviewers: Ayal, hsaito, mkuper
Differential Revision: https://reviews.llvm.org/D51313
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This is fix for PR38786.
First order recurrence phis were incorrectly treated as uniform,
which caused them to be vectorized as uniform instructions.
Patch by Ayal Zaks and Orivej Desh!
Reviewed by: Anna
Differential Revision: https://reviews.llvm.org/D51639
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Summary:
Avoid "count" if possible -> use "find" to check for the existence of keys.
Passed llvm test suite.
Reviewers: fhahn, dcaballe, mkuper, rengolin
Reviewed By: fhahn
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D51054
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Summary:
Follow up change to rL339703, where we now vectorize loops with non-phi
instructions used outside the loop. Note that the cyclic dependency
identification occurs when identifying reduction/induction vars.
We also need to identify that we do not allow users where the PSCEV information
within and outside the loop are different. This was the fix added in rL307837
for PR33706.
Reviewers: Ayal, mkuper, fhahn
Subscribers: javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D50778
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Summary:
This patch teaches the loop vectorizer to vectorize loops with non
header phis that have have outside uses. This is because the iteration
dependence distance for these phis can be widened upto VF (similar to
how we do for induction/reduction) if they do not have a cyclic
dependence with header phis. When identifying reduction/induction/first
order recurrence header phis, we already identify if there are any cyclic
dependencies that prevents vectorization.
The vectorizer is taught to extract the last element from the vectorized
phi and update the scalar loop exit block phi to contain this extracted
element from the vector loop.
This patch can be extended to vectorize loops where instructions other
than phis have outside uses.
Reviewers: Ayal, mkuper, mssimpso, efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50579
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339703 91177308-0d34-0410-b5e6-96231b3b80d8
The patch introduces dominator analysis for VPBlockBases and extend
VPlan's GraphTraits specialization with the required interfaces. Dominator
analysis will be necessary to perform some H-CFG transformations and
to introduce VPLoopInfo (LoopInfo analysis on top of the VPlan representation).
Reviewers: fhahn, rengolin, mkuper, hfinkel, mssimpso
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D48815
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Summary: truncateToMinimalBitWidths() doesn't handle all Instructions and the worst case is compiler crash via llvm_unreachable(). Fix is to add a case to handle PHINode and changed the worst case to NO-OP (from compiler crash).
Reviewers: sbaranga, mssimpso, hsaito
Reviewed By: hsaito
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49461
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337861 91177308-0d34-0410-b5e6-96231b3b80d8
This patch introduces a VPValue in VPBlockBase to represent the condition
bit that is used as successor selector when a block has multiple successors.
This information wasn't necessary until now, when we are about to introduce
outer loop vectorization support in VPlan code gen.
Reviewers: fhahn, rengolin, mkuper, hfinkel, mssimpso
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D48814
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This is a minor fix for LV cost model, where the cost for VF=2 was
computed twice when the vectorization of the loop was forced without
specifying a VF.
Reviewers: xusx595, hsaito, fhahn, mkuper
Reviewed By: hsaito, xusx595
Differential Revision: https://reviews.llvm.org/D48048
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Currently SmallSet<PointerTy> inherits from SmallPtrSet<PointerTy>. This
patch replaces such types with SmallPtrSet, because IMO it is slightly
clearer and allows us to get rid of unnecessarily including SmallSet.h
Reviewers: dblaikie, craig.topper
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D47836
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SmallSet forwards to SmallPtrSet for pointer types. SmallPtrSet supports iteration, but a normal SmallSet doesn't. So if it wasn't for the forwarding, this wouldn't work.
These places were found by hiding the begin/end methods in the SmallSet forwarding
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334343 91177308-0d34-0410-b5e6-96231b3b80d8
This patch moves the recipe-creation functions out of
LoopVectorizationPlanner, which should do the high-level
orchestration of the transformations.
Reviewers: dcaballe, rengolin, hsaito, Ayal
Reviewed By: dcaballe
Differential Revision: https://reviews.llvm.org/D47595
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This first step separates VPInstruction-based and VPRecipe-based
VPlan creation, which should make it easier to migrate to VPInstruction
based code-gen step by step.
Reviewers: Ayal, rengolin, dcaballe, hsaito, mkuper, mzolotukhin
Reviewed By: dcaballe
Subscribers: bollu, tschuett, rkruppe, llvm-commits
Differential Revision: https://reviews.llvm.org/D47477
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334284 91177308-0d34-0410-b5e6-96231b3b80d8
Patch #3 from VPlan Outer Loop Vectorization Patch Series #1
(RFC: http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html).
Expected to be NFC for the current inner loop vectorization path. It
introduces the basic algorithm to build the VPlan plain CFG (single-level
CFG, no hierarchical CFG (H-CFG), yet) in the VPlan-native vectorization
path using VPInstructions. It includes:
- VPlanHCFGBuilder: Main class to build the VPlan H-CFG (plain CFG without nested regions, for now).
- VPlanVerifier: Main class with utilities to check the consistency of a H-CFG.
- VPlanBlockUtils: Main class with utilities to manipulate VPBlockBases in VPlan.
Reviewers: rengolin, fhahn, mkuper, mssimpso, a.elovikov, hfinkel, aprantl.
Differential Revision: https://reviews.llvm.org/D44338
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The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332240 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Broadcast code generation emitted instructions in pre-header, while the instruction they are dependent on in the vector loop body.
This resulted in an IL verification error ---- value used before defined.
Reviewers: rengolin, fhahn, hfinkel
Reviewed By: rengolin, fhahn
Subscribers: dcaballe, Ka-Ka, llvm-commits
Differential Revision: https://reviews.llvm.org/D46302
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331799 91177308-0d34-0410-b5e6-96231b3b80d8
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
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Summary:
This is a fix for PR23997.
The loop vectorizer is not preserving the inbounds property of GEPs that it creates.
This is inhibiting some optimizations. This patch preserves the inbounds property in
the case where a load/store is being fed by an inbounds GEP.
Reviewers: mkuper, javed.absar, hsaito
Reviewed By: hsaito
Subscribers: dcaballe, hsaito, llvm-commits
Differential Revision: https://reviews.llvm.org/D46191
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331269 91177308-0d34-0410-b5e6-96231b3b80d8
This patch updates some code responsible the skip debug info to use
BasicBlock::instructionsWithoutDebug. I think this makes things
slightly simpler and more direct.
Reviewers: mkuper, rengolin, dcaballe, aprantl, vsk
Reviewed By: rengolin
Differential Revision: https://reviews.llvm.org/D46254
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