This reverts the revert commit 58326f1d5b5b379590af92dd129b2f3b3e96af46.
The build failure in sanitizer stage2 builds has been fixed with
0d39fe6f5bb3edf0bddec09a8c6417377390aeac.
Original commit message:
Model updating IV users directly in VPlan, replace fixupIVUsers.
Now simple extracts are created for all phis in the exit block during
initial VPlan construction. A later VPlan transform
(optimizeInductionExitUsers) replaces extracts of inductions with
their pre-computed values if possible.
This completes the transition towards modeling all live-outs directly in
VPlan.
There are a few follow-ups:
* emit extracts initially also for resume phis, and optimize them
tougher with IV exit users
* support for VPlans with multiple exits in optimizeInductionExitUsers.
Depends on https://github.com/llvm/llvm-project/pull/110004,
https://github.com/llvm/llvm-project/pull/109975 and
https://github.com/llvm/llvm-project/pull/112145.
Model updating IV users directly in VPlan, replace fixupIVUsers.
Now simple extracts are created for all phis in the exit block during
initial VPlan construction. A later VPlan transform
(optimizeInductionExitUsers) replaces extracts of inductions with
their pre-computed values if possible.
This completes the transition towards modeling all live-outs directly in
VPlan.
There are a few follow-ups:
* emit extracts initially also for resume phis, and optimize them
tougher with IV exit users
* support for VPlans with multiple exits in optimizeInductionExitUsers.
Depends on https://github.com/llvm/llvm-project/pull/110004,
https://github.com/llvm/llvm-project/pull/109975 and
https://github.com/llvm/llvm-project/pull/112145.
As a first step to move towards modeling the full skeleton in VPlan,
start by wrapping IR blocks created during legacy skeleton creation in
VPIRBasicBlocks and hook them into the VPlan. This means the skeleton
CFG is represented in VPlan, just before execute. This allows moving
parts of skeleton creation into recipes in the VPBBs gradually.
Note that this allows retiring some manual DT updates, as this will be
handled automatically during VPlan execution.
PR: https://github.com/llvm/llvm-project/pull/114292
This moves printing of the final VPlan to ::execute. This ensures the
final VPlan is printed, including recipes that get introduced by late,
lowering transforms and skeleton construction.
Split off from https://github.com/llvm/llvm-project/pull/114292, to
simplify the diff.
Update VPlan to include the scalar loop header. This allows retiring
VPLiveOut, as the remaining live-outs can now be handled by adding
operands to the wrapped phis in the scalar loop header.
Note that the current version only includes the scalar loop header, no
other loop blocks and also does not wrap it in a region block.
PR: https://github.com/llvm/llvm-project/pull/109975
Refactors VPVectorPointerRecipe to use the VF VPValue to obtain the
runtime VF, similar to #95305.
Since only reverse vector pointers require the runtime VF, the patch
sets VPUnrollPart::PartOpIndex to 1 for vector pointers and 2 for
reverse vector pointers. As a result, the generation of reverse vector
pointers is moved into a separate recipe.
There are a number of places where we call getSmallConstantMaxTripCount
without passing a vector of predicates:
getSmallBestKnownTC
isIndvarOverflowCheckKnownFalse
computeMaxVF
isMoreProfitable
I've changed all of these to now pass in a predicate vector so that
we get the benefit of making better vectorisation choices when we
know the max trip count for loops that require SCEV predicate checks.
I've tried to add tests that cover all the cases affected by these
changes.
This patch implements explicit unrolling by UF as VPlan transform. In
follow up patches this will allow simplifying VPTransform state (no need
to store unrolled parts) as well as recipe execution (no need to
generate code for multiple parts in an each recipe). It also allows for
more general optimziations (e.g. avoid generating code for recipes that
are uniform-across parts).
It also unifies the logic dealing with unrolled parts in a single place,
rather than spreading it out across multiple places (e.g. VPlan post
processing for header-phi recipes previously.)
In the initial implementation, a number of recipes still take the
unrolled part as additional, optional argument, if their execution
depends on the unrolled part.
The computation for start/step values for scalable inductions changed
slightly. Previously the step would be computed as scalar and then
splatted, now vscale gets splatted and multiplied by the step in a
vector mul.
This has been split off https://github.com/llvm/llvm-project/pull/94339
which also includes changes to simplify VPTransfomState and recipes'
::execute.
The current version mostly leaves existing ::execute untouched and
instead sets VPTransfomState::UF to 1.
A follow-up patch will clean up all references to VPTransformState::UF.
Another follow-up patch will simplify VPTransformState to only store a
single vector value per VPValue.
PR: https://github.com/llvm/llvm-project/pull/95842
Add a new VPIRInstruction recipe to wrap existing IR instructions not to
be modified during execution, execept for PHIs. For PHIs, a single
VPValue
operand is allowed, and it is used to add a new incoming value for the
single predecessor VPBB. Expect PHIs, VPIRInstructions cannot have any
operands.
Depends on https://github.com/llvm/llvm-project/pull/100658.
PR: https://github.com/llvm/llvm-project/pull/100735
Use getBestVF to select VF up-front and only use
selectVectorizationFactor to get the VF legacy VF to check the
vectorization decision matches the VPlan-based cost model.
PR: https://github.com/llvm/llvm-project/pull/103033
Now that the branches to the scalar epilogue are modeled in VPlan
directly, check the VPlan to see if a scalar epilogue is required.
Preparation for https://github.com/llvm/llvm-project/pull/100658.
Replace getBestPlan by getBestVF which simply finds the best
VF out of the VFs for the available VPlans.
Then use getBestPlan to retrieve the corresponding VPlan.
This allows using getBestVF & getBestPlan for epilogue vectorization
as well. As the same plan may be used to vectorize both the main
and epilogue loop, restricting the VF of the best plan would cause
issues.
PR: https://github.com/llvm/llvm-project/pull/98821
Follow-up to ba8126b6fef79.
If a scalar epilogue is required, users outside the loop won't use
live-outs from the vector loop but from the scalar epilogue. Ignore them if
that is the case.
This fixes another case where the VPlan-based cost-model more accurately
computes cost.
Fixes https://github.com/llvm/llvm-project/issues/100464.
I was comparing some SPEC CPU 2017 benchmarks across rva22u64 and
rva22u64_v, and noticed that in a few cases that rva22u64_v was
considerably slower.
One of them was 519.lbm_r, which has a large loop that was being
unprofitably vectorized. It has an if/else in the loop which requires
large amounts of predication when vectorized, but despite the loop
vectorizer taking this into account the vector cost came out as cheaper
than the scalar.
It looks like the reason for this is because we cost scalar floating
point ops as 2, but their vector equivalents as 1 (for LMUL 1). This
comes from how we use BasicTTIImpl for scalars which treats floats as
twice as expensive as integers.
This patch doubles the cost of vector floating point arithmetic ops so
that they're at least as expensive as their scalar counterparts, which
gives a 13% speedup on 519.lbm_r at -O3 on the spacemit-x60.
Fixes#62576 (the last point there about scalar fsub/fmul)
This reverts commit 6f538f6a2d3224efda985e9eb09012fa4275ea92.
A number of crashes have been fixed by separate fixes, including
ttps://github.com/llvm/llvm-project/pull/96622. This version of the
PR also pre-computes the costs for branches (except the latch) instead
of computing their costs as part of costing of replicate regions, as
there may not be a direct correspondence between original branches and
number of replicate regions.
Original message:
This adds a new interface to compute the cost of recipes, VPBasicBlocks,
VPRegionBlocks and VPlan, initially falling back to the legacy cost model
for all recipes. Follow-up patches will gradually migrate recipes to
compute their own costs step-by-step.
It also adds getBestPlan function to LVP which computes the cost of all
VPlans and picks the most profitable one together with the most
profitable VF.
The VPlan selected by the VPlan cost model is executed and there is an
assert to catch cases where the VPlan cost model and the legacy cost
model disagree. Even though I checked a number of different build
configurations on AArch64 and X86, there may be some differences
that have been missed.
Additional discussions and context can be found in @arcbbb's
https://github.com/llvm/llvm-project/pull/67647 and
https://github.com/llvm/llvm-project/pull/67934 which is an earlier
version of the current PR.
PR: https://github.com/llvm/llvm-project/pull/92555
This patch moves branch condition creation to enter the scalar epilogue
loop to VPlan. Modeling the branch in the middle block also requires
modeling the successor blocks. This is done using the recently
introduced VPIRBasicBlock.
Note that the middle.block is still created as part of the skeleton and
then patched in during VPlan execution. Unfortunately the skeleton needs
to create the middle.block early on, as it is also used for induction
resume value creation and is also needed to properly update the
dominator tree during skeleton creation.
After this patch lands, I plan to move induction resume value and phi
node creation in the scalar preheader to VPlan. Once that is done, we
should be able to create the middle.block in VPlan directly.
This is a re-worked version based on the earlier
https://reviews.llvm.org/D150398 and the main change is the use of
VPIRBasicBlock.
Depends on https://github.com/llvm/llvm-project/pull/92525
PR: https://github.com/llvm/llvm-project/pull/92651
This reverts commit 242cc200ccb24e22eaf54aed7b0b0c84cfc54c0b and
eea150c84053035163f307b46549a2997a343ce9, as it is causing a build bot
failure and there have been a number of crashes reported at
https://github.com/llvm/llvm-project/pull/92555
This reverts commit 6f538f6a2d3224efda985e9eb09012fa4275ea92.
Extra tests for crashes discovered when building Chromium have been
added in fb86cb7ec157689e, 3be7312f81ad2.
Original message:
This adds a new interface to compute the cost of recipes, VPBasicBlocks,
VPRegionBlocks and VPlan, initially falling back to the legacy cost model
for all recipes. Follow-up patches will gradually migrate recipes to
compute their own costs step-by-step.
It also adds getBestPlan function to LVP which computes the cost of all
VPlans and picks the most profitable one together with the most
profitable VF.
The VPlan selected by the VPlan cost model is executed and there is an
assert to catch cases where the VPlan cost model and the legacy cost
model disagree. Even though I checked a number of different build
configurations on AArch64 and X86, there may be some differences
that have been missed.
Additional discussions and context can be found in @arcbbb's
https://github.com/llvm/llvm-project/pull/67647 and
https://github.com/llvm/llvm-project/pull/67934 which is an earlier
version of the current PR.
PR: https://github.com/llvm/llvm-project/pull/92555
This reverts commit 90fd99c0795711e1cf762a02b29b0a702f86a264.
This reverts commit 43e6f46936e177e47de6627a74b047ba27561b44.
Causes crashes, see comments on https://github.com/llvm/llvm-project/pull/92555.
This reverts commit 46080abe9b136821eda2a1a27d8a13ceac349f8c.
Extra tests have been added in 52d29eb287.
Original message:
This adds a new interface to compute the cost of recipes, VPBasicBlocks,
VPRegionBlocks and VPlan, initially falling back to the legacy cost model
for all recipes. Follow-up patches will gradually migrate recipes to
compute their own costs step-by-step.
It also adds getBestPlan function to LVP which computes the cost of all
VPlans and picks the most profitable one together with the most
profitable VF.
The VPlan selected by the VPlan cost model is executed and there is an
assert to catch cases where the VPlan cost model and the legacy cost
model disagree. Even though I checked a number of different build
configurations on AArch64 and X86, there may be some differences
that have been missed.
Additional discussions and context can be found in @arcbbb's
https://github.com/llvm/llvm-project/pull/67647 and
https://github.com/llvm/llvm-project/pull/67934 which is an earlier
version of the current PR.
PR: https://github.com/llvm/llvm-project/pull/92555
This adds a new interface to compute the cost of recipes, VPBasicBlocks,
VPRegionBlocks and VPlan, initially falling back to the legacy cost model
for all recipes. Follow-up patches will gradually migrate recipes to
compute their own costs step-by-step.
It also adds getBestPlan function to LVP which computes the cost of all
VPlans and picks the most profitable one together with the most
profitable VF.
The VPlan selected by the VPlan cost model is executed and there is an
assert to catch cases where the VPlan cost model and the legacy cost
model disagree. Even though I checked a number of different build
configurations on AArch64 and X86, there may be some differences
that have been missed.
Additional discussions and context can be found in @arcbbb's
https://github.com/llvm/llvm-project/pull/67647 and
https://github.com/llvm/llvm-project/pull/67934 which is an earlier
version of the current PR.
PR: https://github.com/llvm/llvm-project/pull/92555
This patch is moving out following intrinsics:
* vector.interleave2/deinterleave2
* vector.reverse
* vector.splice
from the experimental namespace.
All these intrinsics exist in LLVM for more than a year now, and are
widely used, so should not be considered as experimental.
Some optimizations are apply after UF and VF have been chosen. This
patch adds an extra print of the final VPlan just before
codegen/execution.
In the future, there will be additional transforms that are applied
later (interleaving for example).
PR: https://github.com/llvm/llvm-project/pull/82269
Move vector pointer generation to a separate VPVectorPointerRecipe.
This untangles address computation from the memory recipes future
and is also needed to enable explicit unrolling in VPlan.
https://github.com/llvm/llvm-project/pull/72164
This patch starts initial modeling of VF * UF in VPlan.
Initially, introduce a dedicated VFxUF VPValue, which is then
populated during VPlan::prepareToExecute. Initially, the VF * UF
applies only to the main vector loop region. Once we extend the
scope of VPlan in the future, we may want to associate different VFxUFs
with different vector loop regions (e.g. the epilogue vector loop)
This allows explicitly parameterizing recipes that rely on the
VF * UF, like the canonical induction increment. At the moment, this
mainly helps to avoid generating some duplicated calls to vscale with
scalable vectors. It should also allow using EVL as induction increments
explicitly in D99750. Referring to VF * UF is also needed in other
places that we plan to migrate to VPlan, like the minimum trip count
check during skeleton creation.
The first version creates the value for VF * UF directly in
prepareToExecute to limit the scope of the patch. A follow-on patch will
model VF * UF computation explicitly in VPlan using recipes.
Moved from Phabricator (https://reviews.llvm.org/D157322)
This patch implements getCFInstrCost TTI hook that mostly affects
LoopVectorizer decisions. It sets zero cost for PHI nodes and zero
throughput cost for branches (assuming that branches are likely to
be predicted). The implementation is similar to X86/AArch64/PowerPC
targets and reduces loop cost by excluding induction PHIs/loop latch
branches, which in turn leads to selecting smaller vectorization
factor.
Model wrap flags directly using VPRecipeWithIRFlags and clean up the
duplicated *NUW opcodes.
D157144 will build on this and also model FMFs for VPInstruction.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D157194
Use the printOperands for printing VPInstruction's operands to be more
in line with other recipes and ensure consistent printing after D15719.
Also removes some stray spaces in print output.
vrgather.vv across multiple vector registers (i.e. LMUL > 1) requires all to all data movement. This includes two conceptual sets of changes:
For permutes, we were modeling these as being linear in LMUL.
For reverse, we were modeling them as being fixed cost in LMUL.
Both were wrong, and have been adjusted to O(LMUL^2). Noticed via code inspection while looking at something else.
Its worth asking whether we should be lowering reverse to something other than a vrgather at high LMULs. That shuffle is quite expensive. (Future work)
Differential Revision: https://reviews.llvm.org/D152019
Now that IR flags are modeled as part of VPRecipeWithIRFlags, include
the flags when printing recipes.
Depends on D150027.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D150029
Generally, the cost of a memory op will scale with the number of vector registers accessed. Machines might exist which have a narrow memory access than vector register width, but machines with a wider memory access width than vector register width seem unlikely.
I noticed this because we were preferring wide loads + deinterleaves on examples where the cost of a short gather (actually a strided load) would be better. Touching 8 vector registers instead of doing a 4 element gather is not a good tradeoff.
Differential Revision: https://reviews.llvm.org/D147470
Previously, while calculating register usage due to invariants, it was assumed that invariant would always be part of widening
instructions. This resulted in calculating vector register types for vectors which cant be legalized(check the newly added test for more details).
An invariant might not always need a vector register. For e.g., invariant might just be used for iteration check.
This patch checks if the invariant is part of any widening instruction and considers register usage accordingly. Fixes issue 60493
Differential Revision: https://reviews.llvm.org/D143422
Previously, while calculating register usage due to invariants, it was assumed that invariant would always be part of widening
instructions. This resulted in calculating vector register types for vectors which cant be legalized(check the newly added test for more details).
An invariant might not always need a vector register. For e.g., invariant might just be used for iteration check.
This patch checks if the invariant is part of any widening instruction and considers register usage accordingly. Fixes issue 60493
Differential Revision: https://reviews.llvm.org/D143422
It's less clear with scalable vectors than fixed length vectors that
interleaving exposes more ILP, as scalable vectors can be thought of a
sort of hardware form of interleaving, especially with larger LMULs.
This also addresses the unexpected additional unrolling that occurs when
using larger LMULs in the loop vectorizer.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D144485
This reuses the routine implemented in 0e6f0b7 to implement several existing TODOs. Many of the operations scale linearly with LMUL; this change represents that in the cost model.
Differential Revision: https://reviews.llvm.org/D139039
This reverts commit bf15f1e489aa2f1ac13268c9081a992a8963eb5b.
The updated version fixes a crash by checking the induction kind instead
of the opcode; for integer inductions, the step is always added, but the
opcode might not be set.
