Extracting to the same index that we are going to insert back into
allows forming select ("blend") shuffles and enables further transforms.
Admittedly, this is a quick-fix for a more general problem that I'm
hoping to solve by adding transforms for patterns that start with an
insertelement.
But this might resolve some regressions known to be caused by the
extract-extract transform (although I have not gotten more details on
those yet).
In the motivating case from PR34724:
https://bugs.llvm.org/show_bug.cgi?id=34724
The combination of subsequent instcombine and codegen transforms gets us this improvement:
vmovshdup %xmm0, %xmm2 ## xmm2 = xmm0[1,1,3,3]
vhaddps %xmm1, %xmm1, %xmm4
vmovshdup %xmm1, %xmm3 ## xmm3 = xmm1[1,1,3,3]
vaddps %xmm0, %xmm2, %xmm0
vaddps %xmm1, %xmm3, %xmm1
vshufps $200, %xmm4, %xmm0, %xmm0 ## xmm0 = xmm0[0,2],xmm4[0,3]
vinsertps $177, %xmm1, %xmm0, %xmm0 ## xmm0 = zero,xmm0[1,2],xmm1[2]
-->
vmovshdup %xmm0, %xmm2 ## xmm2 = xmm0[1,1,3,3]
vhaddps %xmm1, %xmm1, %xmm1
vaddps %xmm0, %xmm2, %xmm0
vshufps $200, %xmm1, %xmm0, %xmm0 ## xmm0 = xmm0[0,2],xmm1[0,3]
Differential Revision: https://reviews.llvm.org/D76623
bitcast (shuf V, MaskC) --> shuf (bitcast V), MaskC'
We do not attempt this in InstCombine because we do not want to change
types and create new shuffle ops that are potentially not lowered as
well as the original code. Here, we can check the cost model to see if
it is worthwhile.
I've aggressively enabled this transform even if the types are the same
size and/or equal cost because moving the bitcast allows InstCombine to
make further simplifications.
In the motivating cases from PR35454:
https://bugs.llvm.org/show_bug.cgi?id=35454
...this is enough to let instcombine and the backend eliminate the
redundant shuffles, but we probably want to extend VectorCombine to
handle the inverse pattern (shuffle-of-bitcast) to get that
simplification directly in IR.
Differential Revision: https://reviews.llvm.org/D76727
Instead, represent the mask as out-of-line data in the instruction. This
should be more efficient in the places that currently use
getShuffleVector(), and paves the way for further changes to add new
shuffles for scalable vectors.
This doesn't change the syntax in textual IR. And I don't currently plan
to change the bitcode encoding in this patch, although we'll probably
need to do something once we extend shufflevector for scalable types.
I expect that once this is finished, we can then replace the raw "mask"
with something more appropriate for scalable vectors. Not sure exactly
what this looks like at the moment, but there are a few different ways
we could handle it. Maybe we could try to describe specific shuffles.
Or maybe we could define it in terms of a function to convert a fixed-length
array into an appropriate scalable vector, using a "step", or something
like that.
Differential Revision: https://reviews.llvm.org/D72467
In InnerLoopVectorizer::getOrCreateTripCount, when the backedge taken
count is a SCEV add expression, its type is defined by the type of the
last operand of the add expression.
In the test case from PR45259, this last operand happens to be a
pointer, which (according to llvm::Type) does not have a primitive size
in bits. In this case, LoopVectorize fails to truncate the SCEV and
crashes as a result.
Uing ScalarEvolution::getTypeSizeInBits makes the truncation work as expected.
https://bugs.llvm.org/show_bug.cgi?id=45259
Differential Revision: https://reviews.llvm.org/D76669
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
This untangles the logic in widenIntOrFpInduction in order to make more
explicit and visible how exactly the induction variable is lowered.
Differential Revision: https://reviews.llvm.org/D76686
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
We need to insert into the Visited set at the same time we insert
into the worklist. Otherwise we may end up pushing the same
instruction to the worklist multiple times, and only adding it to
the visited set later.
The latest improvements to VPValue printing make this mapping clear when
printing the operand. Printing the mapping separately is not required
any longer.
Reviewers: rengolin, hsaito, Ayal, gilr
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D76375
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
The existence of the class is more confusing than helpful, I think; the
commonality is mostly just "GEP is legal", which can be queried using
APIs on GetElementPtrInst.
Differential Revision: https://reviews.llvm.org/D75660
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
Summary:
SLPVectorizer try to vectorize list of scalar instructions of the same type,
instructions already vectorized are rejected through isValidElementType().
Without this patch, tryToVectorizeList() will first try to determine vectorization
factor of a list of Instructions before checking whether each instruction has unsupported
type or not. For instructions already vectorized for SVE, it will crash at getVectorElementSize(),
where it try to return a fixed size.
This patch make sure invalid element types are rejected before trying to get vectorization
factor. This make sure we are not trying to vectorize instructions already vectorized.
Reviewers: sdesmalen, efriedma, spatel, RKSimon, ABataev, apazos, rengolin
Reviewed By: efriedma
Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76017
Summary:
Support ConstantInt::get() and Constant::getAllOnesValue() for scalable
vector type, this requires ConstantVector::getSplat() to take in 'ElementCount',
instead of 'unsigned' number of element count.
This change is needed for D73753.
Reviewers: sdesmalen, efriedma, apazos, spatel, huntergr, willlovett
Reviewed By: efriedma
Subscribers: tschuett, hiraditya, rkruppe, psnobl, cfe-commits, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74386
Refines the gather/scatter cost model, but also changes the TTI
function getIntrinsicInstrCost to accept an additional parameter
which is needed for the gather/scatter cost evaluation.
This did require trivial changes in some non-ARM backends to
adopt the new parameter.
Extending gathers and truncating scatters are now priced cheaper.
Differential Revision: https://reviews.llvm.org/D75525
It seems like the SLPVectorizer is currently not aware of vector
versions of functions provided by libraries like Accelerate [1].
This patch updates SLPVectorizer to use the same infrastructure
the LoopVectorizer uses to detect vectorizable library functions.
For calls, it computes the cost of an intrinsic call (existing behavior)
and the cost of a vector function library call, if available. Like
LoopVectorizer, it assumes the cost of the vector function is simply the
cost of a call to a vector function.
[1] https://developer.apple.com/documentation/accelerate
Reviewers: ABataev, RKSimon, spatel
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D75878
opcode (extelt V0, Ext0), (ext V1, Ext1) --> extelt (opcode (splat V0, Ext0), V1), Ext1
The first part of this patch generalizes the cost calculation to accept
different extraction indexes. The second part creates a shuffle+extract
before feeding into the existing code to create a vector op+extract.
The patch conservatively uses "TargetTransformInfo::SK_PermuteSingleSrc"
rather than "TargetTransformInfo::SK_Broadcast" (splat specifically
from element 0) because we do not have a more general "SK_Splat"
currently. That does not affect any of the current regression tests,
but we might be able to find some cost model target specialization where
that comes into play.
I suspect that we can expose some missing x86 horizontal op codegen with
this transform, so I'm speculatively adding a debug flag to disable the
binop variant of this transform to allow easier testing.
The test changes show that we're sensitive to cost model diffs (as we
should be), so that means that patches like D74976
should have better coverage.
Differential Revision: https://reviews.llvm.org/D75689
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
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
getReductionVars, getInductionVars and getFirstOrderRecurrences were all
being returned from LoopVectorizationLegality as pointers to lists. This
just changes them to be references, cleaning up the interface slightly.
Differential Revision: https://reviews.llvm.org/D75448
This change adds an assertion to prevent tricky bug related to recursive
approach of building vectorization tree. For loop below takes number of
operands directly from tree entry rather than from scalars.
If the entry at this moment turns out incomplete (i.e. not all operands set)
then not all the dependencies will be seen by the scheduler.
This can lead to failed scheduling (and thus failed vectorization)
for perfectly vectorizable tree.
Here is code example which is likely to fire the assertion:
for (i : VL0->getNumOperands()) {
...
TE->setOperand(i, Operands);
buildTree_rec(Operands, Depth + 1,...);
}
Correct way is two steps process: first set all operands to a tree entry
and then recursively process each operand.
Differential Revision: https://reviews.llvm.org/D75296
This patch deletes some dead code out of SLP vectorizer.
Couple of changes taken out of D57059 to slightly lighten it
plus one more similar case fixed.
Differential Revision: https://reviews.llvm.org/D75276
A recent commit
(https://reviews.llvm.org/rG66c120f02560ef528a60924104ead66f330190f1) changed
the cost for calls to functions that have a vector version for some
vectorization factor. However, no check is performed for whether the
vectorization factor matches the current one being cost modeled. This leads to
attempts to widen call instructions to a vectorization factor for which such a
function does not exist, which in turn leads to an assertion failure.
This patch adds the check for vectorization factor (i.e. not just that the
called function has a vector version for some VF, but that it has a vector
version for this VF).
Differential revision: https://reviews.llvm.org/D74944
As suggested in D75145 -
I'm not sure why, but several passes have this kind of disable/enable flag
implemented at the pass manager level. But that means we have to duplicate
the flag for both pass managers and add code to check the flag every time
the pass appears in the pipeline.
We want a debug option to see if this pass is misbehaving regardless of the
pass managers, so just add a disablement check at the single point before
any transforms run.
Differential Revision: https://reviews.llvm.org/D75204
Code duplication (subsequently removed by refactoring) allowed
a logic discrepancy to creep in here.
We were being conservative about creating a vector binop -- but
not a vector cmp -- in the case where a vector op has the same
estimated cost as the scalar op. We want to be more aggressive
here because that can allow other combines based on reduced
instruction count/uses.
We can reverse the transform in DAGCombiner (potentially with a
more accurate cost model) if this causes regressions.
AFAIK, this does not conflict with InstCombine. We have a
scalarize transform there, but it relies on finding a constant
operand or a matching insertelement, so that means it eliminates
an extractelement from the sequence (so we won't have 2 extracts
by the time we get here if InstCombine succeeds).
Differential Revision: https://reviews.llvm.org/D75062
This should be the last step in the current cleanup.
Follow-ups should resolve the TODO about cost calc
and enable the more general case where we extract
different elements.
ToVectorTy is defined and used in multiple places. Hoist it to
VectorUtils.h to avoid duplication and improve re-usability.
Reviewers: rengolin, hsaito, Ayal, gilr, fpetrogalli
Reviewed By: fpetrogalli
Differential Revision: https://reviews.llvm.org/D74959
Essentially, fold OrderedBasicBlock into BasicBlock, and make it
auto-invalidate the instruction ordering when new instructions are
added. Notably, we don't need to invalidate it when removing
instructions, which is helpful when a pass mostly delete dead
instructions rather than transforming them.
The downside is that Instruction grows from 56 bytes to 64 bytes. The
resulting LLVM code is substantially simpler and automatically handles
invalidation, which makes me think that this is the right speed and size
tradeoff.
The important change is in SymbolTableTraitsImpl.h, where the numbering
is invalidated. Everything else should be straightforward.
We probably want to implement a fancier re-numbering scheme so that
local updates don't invalidate the ordering, but I plan for that to be
future work, maybe for someone else.
Reviewed By: lattner, vsk, fhahn, dexonsmith
Differential Revision: https://reviews.llvm.org/D51664
The index of an ExtractElementInst is not guaranteed to be a
ConstantInt. It can be any integer value. Check explicitly for
ConstantInts.
The new test cases illustrate scenarios where we crash without
this patch. I've also added another test case to check the matching
of extractelement vector ops works.
Reviewers: RKSimon, ABataev, dtemirbulatov, vporpo
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D74758
getOperationCost() is not the cost we wanted; that's not the
throughput value that the rest of the calculation uses.
We may want to switch everything in this code to use the
getInstructionThroughput() wrapper to avoid these kinds of
problems, but I'll look at that as a follow-up because that
can create other logical diffs via using optional parameters
(we'd need to speculatively create the vector instruction to
make a fair(er) comparison).
binop (extelt X, C), (extelt Y, C) --> extelt (binop X, Y), C
This is a transform that has been considered for canonicalization (instcombine)
in the past because it reduces instruction count. But as shown in the x86 tests,
it's impossible to know if it's profitable without a cost model. There are many
potential target constraints to consider.
We have implemented similar transforms in the backend (DAGCombiner and
target-specific), but I don't think we have this exact fold there either (and if
we did it in SDAG, it wouldn't work across blocks).
Note: this patch was intended to handle the more general case where the extract
indexes do not match, but it got too big, so I scaled it back to this pattern
for now.
Differential Revision: https://reviews.llvm.org/D74495
This is apparently worse than 1-byte alignment. This does not attempt
to decompose 2-byte aligned wide stores, but will stop trying to
produce them.
Also fix bug in LoadStoreVectorizer which was decreasing the alignment
and vectorizing stack accesses. It was assuming a stack object was an
alloca that could have its base alignment changed, which is not true
if the pointer is derived from a function argument.
The variable was added to the initial commit via copy/paste of existing
code, but it wasn't actually used in the code. We can add it back with
the proper usage if/when that is needed.
We have several bug reports that could be characterized as "reducing scalarization",
and this topic was also raised on llvm-dev recently:
http://lists.llvm.org/pipermail/llvm-dev/2020-January/138157.html
...so I'm proposing that we deal with these patterns in a new, lightweight IR vector
pass that runs before/after other vectorization passes.
There are 4 alternate options that I can think of to deal with this kind of problem
(and we've seen various attempts at all of these), but they all have flaws:
InstCombine - can't happen without TTI, but we don't want target-specific
folds there.
SDAG - too late to assist other vectorization passes; TLI is not equipped
for these kind of cost queries; limited to a single basic block.
CGP - too late to assist other vectorization passes; would need to re-implement
basic cleanups like CSE/instcombine.
SLP - doesn't fit with existing transforms; limited to a single basic block.
This initial patch/transform is based on existing code in AggressiveInstCombine:
we walk backwards through the function looking for a pattern match. But we diverge
from that cost-independent IR canonicalization pass by using TTI to decide if the
vector alternative is profitable.
We probably have at least 10 similar bug reports/patterns (binops, constants,
inserts, cheap shuffles, etc) that would fit in this pass as follow-up enhancements.
It's possible that we could iterate on a worklist to fix-point like InstCombine does,
but it's safer to start with a most basic case and evolve from there, so I didn't
try to do anything fancy with this initial implementation.
Differential Revision: https://reviews.llvm.org/D73480
Dead instructions do not need to be sunk. Currently we try and record
the recipies for them, but there are no recipes emitted for them and
there's nothing to sink. They can be removed from SinkAfter while
marking them for recording.
Fixes PR44634.
Reviewers: rengolin, hsaito, fhahn, Ayal, gilr
Reviewed By: gilr
Differential Revision: https://reviews.llvm.org/D73423
Sanjay Patel