I've changed how we construct the EpilogueVectorizerEpilogueLoop and
EpilogueVectorizerMainLoop classes so that we construct the parent class
with an additional boolean parameter indicating whether we're
vectorising the main or epilogue loop. The
InnerLoopAndEpilogueVectorizer class uses this new argument in
combination with the EpilogueLoopVectorizationInfo struct to set the
right UF and VF values. This then allows EpilogueVectorizerEpilogueLoop
to access the correct values of VF and UF for the main loop, which are
required when setting branch weights in the minimum iteration check
block.
`VPInstruction::Not` which will generate xor instruction is widely used
for the exit condition. This patch make `VPInstruction::Not` generate
scalar `xor` if possible.
This can help reducing the (splat true) in the `xor` and make `xor` be
scalar.
The EVL mask is always defined as `icmp ult (step-vector, EVL)`, so we
only need to generate it once per plan in the header. Then, we replace
all uses of the header mask with the EVL mask, and recursively optimize
the users of EVL mask into EVL recipes. This way, the transformation to
EVL recipes can be done with just a single loop.
Epilogue vectorization currently relies on the resume phi for the
canonical induction being always available, which is why VPPhi are
considered to have side-effects, to prevent their removal.
This patch adds a new ResumeForEpilogue opcode to mark the resume phi as
used for epilogue vectorization. This allows treating VPPhis in general
as not having side-effects, enabling removal of unused VPPhis.
Split up the not clearly named prepareForVectorization transform into
buildVPlan0, which adds the vector preheader, middle and scalar
preheader blocks, as well as the canonical induction recipes and sets
the trip count. The new transform is run directly after building the
plain CFG VPlan initially.
The remaining code handling early exits and adding the branch in the
middle block is renamed to handleEarlyExitsAndAddMiddleCheck and still
runs at the original position.
With the code movement, we only have to add the skeleton once to the
initial VPlan, and cloning will take care of the rest. It will also
enable moving other construction steps to work directly on VPlan0, like
adding resume phis.
PR: https://github.com/llvm/llvm-project/pull/150848
This introduces a new `ptrtoaddr` instruction which is similar to
`ptrtoint` but has two differences:
1) Unlike `ptrtoint`, `ptrtoaddr` does not capture provenance
2) `ptrtoaddr` only extracts (and then extends/truncates) the low
index-width bits of the pointer
For most architectures, difference 2) does not matter since index (address)
width and pointer representation width are the same, but this does make a
difference for architectures that have pointers that aren't just plain
integer addresses such as AMDGPU fat pointers or CHERI capabilities.
This commit introduces textual and bitcode IR support as well as basic code
generation, but optimization passes do not handle the new instruction yet
so it may result in worse code than using ptrtoint. Follow-up changes will
update capture tracking, etc. for the new instruction.
RFC: https://discourse.llvm.org/t/clarifiying-the-semantics-of-ptrtoint/83987/54
Reviewed By: nikic
Pull Request: https://github.com/llvm/llvm-project/pull/139357
Materialize the vector trip count computation using VPInstruction
instead of directly creating IR. This is one of the last few steps
needed to model the full vector skeleton in VPlan. It also simplifies
vector-trip count computations for scalable vectors, as we can re-use
the UF x VF computation.
PR: https://github.com/llvm/llvm-project/pull/151925
Instead of relying on getOrCreateVectorTripCount to initialize
EPI.VectorTripCount, delay initialization after we retrieved the resume
phi and get the trip count from there. This makes the code independent
of legacy vector trip count creation.
Now that VPWidenPointerInductionRecipes are modelled in VPlan in
#148274, we can support them in EVL tail folding.
We need to replace their VFxUF operand with EVL as the increment is not
guaranteed to always be VF on the penultimate iteration, and UF is
always 1 with EVL tail folding.
We also need to move the creation of the backedge value to the latch so
that EVL dominates it.
With this we will no longer fail to convert a VPlan to EVL tail folding,
so adjust tryAddExplicitVectorLength to account for this. This brings us
to 99.4% of all vector loops vectorized on SPEC CPU 2017 with tail
folding vs no tail folding.
The test in only-compute-cost-for-vplan-vfs.ll previously relied on
widened pointer inductions with EVL tail folding to end up in a scenario
with no vector VPlans, so this also replaces it with an unvectorizable
fixed-order recurrence test from
first-order-recurrence-multiply-recurrences.ll that also gets discarded.
The initial VPlan closely reflects the original scalar loop, so unsing
VPWidenPHIRecipe here is premature. Widened phi recipes should only be
introduced together with other widened recipes.
PR: https://github.com/llvm/llvm-project/pull/150847
## Purpose
This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates symbols that were recently
added to LLVM and fixes incorrectly annotated symbols.
## Background
This effort is tracked in #109483. Additional context is provided in
[this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307),
and documentation for `LLVM_ABI` and related annotations is found in the
LLVM repo
[here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst).
## Overview
The bulk of these changes were generated automatically using the
[Interface Definition Scanner (IDS)](https://github.com/compnerd/ids)
tool, followed formatting with `git clang-format`.
The following manual adjustments were also applied after running IDS:
- Add `LLVM_EXPORT_TEMPLATE` and `LLVM_TEMPLATE_ABI` annotations to
explicitly instantiated instances of `llvm::object::SFrameParser`.
## Validation
On Windows 11:
```
cmake -B build -S llvm -G Ninja -DLLVM_ENABLE_PROJECTS="llvm;clang;clang-tools-extra;lldb;lld" -DLLVM_OPTIMIZED_TABLEGEN=ON -DLLVM_BUILD_LLVM_DYLIB=ON -DLLVM_BUILD_LLVM_DYLIB_VIS=ON -DLLVM_LINK_LLVM_DYLIB=ON -DLLVM_BUILD_TESTS=ON -DCLANG_LINK_CLANG_DYLIB=OFF -DCMAKE_BUILD_TYPE=Release
ninja -C build
```
Update handling of canonical IV resume phi for the epilogue loop to make
sure the resume phi for the canonical IV is always the first phi in the
scalar preheader.
This makes it easier to retrieve it in preparePlanForEpilogueVectorLoop.
For now, we keep an assert to make sure we use the same resume phi as
before. This will be removed in the future.
This is the VPWidenPointerInductionRecipe equivalent of #118638, with
the motivation of allowing us to use the EVL as the induction step.
There is a new VPInstruction added, WidePtrAdd to allow adding the step
vector to the induction phi, since VPInstruction::PtrAdd only handles
scalars or multiple scalar lanes.
Originally this transformation was copied from the original recipe's
execute code, but it's since been simplifed by teaching
`unrollWidenInductionByUF` to unroll the recipe, which brings it inline
with VPWidenIntOrFpInductionRecipe.
Move selectInterleaveCount to LoopVectorizationPlanner and retrieve some
information directly from VPlan. Register pressure was already computed
for a VPlan, and with this patch we now also check for reductions
directly on VPlan, as well as checking how many load and store
operations remain in the loop.
This should be mostly NFC, but we may compute slightly different
interleave counts, except for some edge cases, e.g. where dead loads
have been removed. This shouldn't happen in practice, and the patch
doesn't cause changes across a large test corpus on AArch64.
Computing the interleave count based on VPlan allows for making better
decisions in presence of VPlan optimizations, for example when
operations on interleave groups are narrowed.
Note that there are a few test changes for tests that were still
checking the legacy cost-model output when it was computed in
selectInterleaveCount.
PR: https://github.com/llvm/llvm-project/pull/149702
This patch uses VPTypeAnalysis to determine its type since the induction
step is not always a live-in value in the VPlan and may be defined by a
recipe.
We iterate over the scalar costs of instruction when printing costs, and
currently the iteration order is not deterministic. Currently no tests
check the output with multiple instructions in the map, but those will
come soon.
If the instruction is checked for matching the main instruction, need to
check if the opcode of the main instruction is compatible with the
operands of the instruction. If they are not, need to check the
alternate instruction and its operands for compatibility and return
alternate instruction as a match.
Fixes#151699
Fixed check for non-supported binary operations.
If the instruction is checked for matching the main instruction, need to
check if the opcode of the main instruction is compatible with the
operands of the instruction. If they are not, need to check the
alternate instruction and its operands for compatibility and return
alternate instruction as a match.
Fixes#151699
Currently hasEarlyExit returns true, if there are multiple exit blocks.
ExitBlocks contains the wrapped original IR exit blocks. Without
checking the predecessors we incorrectly return true for loops with
multiple countable exits, that have been vectorized by requiring a
scalar epilogue. In that case, the exit blocks will get disconnected.
Fix this by filtering out disconnected exit blocks.
Currently this should only impact the 'early-exit vectorized' statistic.
PR: https://github.com/llvm/llvm-project/pull/151718
Attempt to shrink the size of vector loads where only some of the incoming lanes are used for rebroadcasts in shufflevector instructions.
---------
Co-authored-by: Leon Clark <leoclark@amd.com>
Co-authored-by: Simon Pilgrim <llvm-dev@redking.me.uk>
Explicitly compute the backedge-taken count using VPInstruction. This is
needed to model the full skeleton in VPlan.
NFC modulo some instruction re-ordering.
The operands of the replicate recipe may have been narrowed, resulting
in a narrower result type. Update the type of the cloned instruction to
the correct type.
Fixes https://github.com/llvm/llvm-project/issues/151392.
Update isConditionTrueViaVFAndUF to use the vector trip count if
computable. This is the case when it has been materialized to a
constant. Otherwise fall back to the trip count.
PR: https://github.com/llvm/llvm-project/pull/151034
Make sure to check that the vector trip count is containedin the list of
incoming values to serve as tie-breaker with phis with all-zero incoming
values.
Fixes https://github.com/llvm/llvm-project/issues/151686.
We iterate over InstsToScalarize when printing costs, and currently the
iteration order is not deterministic. Currently no tests check the
output with multiple instructions in InstsToScalarize, but those will
come soon.
When interleaved stores contain gaps, a mask is required to skip the
gaps, regardless of whether scalar epilogues are allowed.
This patch corrects the condition under which a gap mask is needed,
ensuring consistency between the legacy and VPlan-based cost models and
avoiding assertion failures.
Related #149981
