Add 3 new iterator ranges to VPPhiAccessors
* incoming_values(): returns a range over the incoming
values of a phi
* incoming_blocks(): returns a range over the incoming
blocks of a phi
* incoming_values_and_blocks: returns a range over pairs of
incoming values and blocks.
Depends on https://github.com/llvm/llvm-project/pull/124838.
PR: https://github.com/llvm/llvm-project/pull/138472
Materialize VF and VFxUF 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.
This is mostly NFC, although in some cases we remove some unused
computations.
PR: https://github.com/llvm/llvm-project/pull/152879
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.
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
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
```
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.
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
Explicitly compute the backedge-taken count using VPInstruction. This is
needed to model the full skeleton in VPlan.
NFC modulo some instruction re-ordering.
VPVectorPointer for part 0 is just the pointer operand. Simplify it
after unrolling. This removes a large number of redundant GEPs with
index 0.
PR: https://github.com/llvm/llvm-project/pull/149735
This patch adds a new ExtractLane VPInstruction which extracts across
multiple parts using a wide index, to be used in combination with
FirstActiveLane.
The patch updates early-exit codegen to use it instead ExtractElement,
which is only per-part. With this change, interleaving should work
correctly with early-exit loops.
The patch removes the restrictions added in 6f43754e9 (#145877), but
does not yet automatically select interleave counts > 1 for early-exit
loops.
I'll share a patch as follow-up. The cost of extracting a lane adds
non-trivial overhead in the exit block, so that should be considered
when picking the interleave count.
PR: https://github.com/llvm/llvm-project/pull/148817
When looking at some EVL tail folded code in SPEC CPU 2017 I noticed we
sometimes have both VPBlendRecipes and select VPInstructions in the same
plan:
EMIT vp<%active.lane.mask> = active lane mask vp<%5>, vp<%3>
EMIT vp<%7> = icmp ...
EMIT vp<%8> = logical-and vp<%active.lane.mask>, vp<%7>
BLEND ir<%8> = ir<%n.015> ir<%foo>/vp<%8>
EMIT vp<%9> = select vp<%active.lane.mask>, ir<%8>, ir<%n.015>
Since a blend will ultimately generate a chain of selects, we could fold
the blend into the select:
EMIT vp<%active.lane.mask> = active lane mask vp<%5>, vp<%3>
EMIT vp<%7> = icmp ...
EMIT vp<%8> = logical-and vp<%active.lane.mask>, vp<%7>
EMIT ir<%8> = select vp<%8>, ir<%foo>, ir<%n.015>
So as a first step, this patch expands blends to a series of select
instructions, which may allow them to be simplified further with other
select instructions.
Update VPWidenRecipe::clone() to use the constructor w/o mandatory
Instruction, to facilitate cloning VPWidenRecipe without underlying
instructions.
Split off from https://github.com/llvm/llvm-project/pull/148239.
This preserves the nuw/nsw flags on widened truncs by checking for
TruncInst in the VPIRFlags constructor
The motivation for this is to be able to fold away some redundant truncs
feeding into uitofps (or potentially narrow the inductions feeding them)
## Purpose
Export a small number of private LLVM symbols so that unit tests can
still build/run when LLVM is built as a Windows DLL or a shared library
with default hidden symbol visibility.
## Background
The effort to build LLVM as a WIndows DLL is tracked in #109483.
Additional context is provided in [this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307).
Some LLVM unit tests use internal/private symbols that are not part of
LLVM's public interface. When building LLVM as a DLL or shared library
with default hidden symbol visibility, the symbols are not available
when the unit test links against the DLL or shared library.
This problem can be solved in one of two ways:
1. Export the private symbols from the DLL.
2. Link the unit tests against the intermediate static libraries instead
of the final LLVM DLL.
This PR applies option 1. Based on the discussion of option 2 in
#145448, this option is preferable.
## Overview
* Adds a new `LLVM_ABI_FOR_TEST` export macro, which is currently just
an alias for `LLVM_ABI`.
* Annotates the sub-set of symbols under `llvm/lib` that are required to
get unit tests building using the new macro.
A reverse interleave access is essentially composed of multiple
load/store operations with same negative stride, and their addresses are
based on the last lane address of member 0 in the interleaved group.
Currently, we already have VPVectorEndPointerRecipe for computing the
last lane address of consecutive reverse memory accesses. This patch
extends VPVectorEndPointerRecipe to support constant stride and extracts
the reverse interleave group address adjustment from
VPInterleaveRecipe::execute, replacing it with a
VPVectorEndPointerRecipe.
The final goal is to support interleaved accesses with EVL tail folding.
Given that VPInterleaveRecipe is large and tightly coupled — combining
both load and store, and embedding operations like reverse pointer
adjustion (GEP), widen load/store, deinterleave/interleave, and reversal
— breaking it down into smaller, dedicated recipes may allow
VPlanTransforms::tryAddExplicitVectorLength to lower them into EVL-aware
form more effectively.
One foreseeable challenge is that
VPlanTransforms::convertToConcreteRecipes currently runs after
tryAddExplicitVectorLength, so decomposing VPInterleaveRecipe will
likely need to happen earlier in the pipeline to be effective.
VPReductionPHIRecipe doesn't rely on the underlying phi any longer,
allow empty underlying values when cloning. NFC at the moment but will
enable follow-up patches.
This patch adds a new recipe to combine multiple recipes into an
'expression' recipe, which should be considered as single entity for
cost-modeling and transforms. The recipe needs to be 'decomposed', i.e.
replaced by its individual recipes before execute.
This subsumes VPExtendedReductionRecipe and
VPMulAccumulateReductionRecipe and should make it easier to extend to
include more types of bundled patterns, like e.g. extends folded into
loads or various arithmetic instructions, if supported by the target.
It allows avoiding re-creating the original recipes when converting to
concrete recipes, together with removing the need to record various
information. The current version of the patch still retains the original
printing matching VPExtendedReductionRecipe and
VPMulAccumulateReductionRecipe, but this specialized print could be
replaced with printing the bundled recipes directly.
PR: https://github.com/llvm/llvm-project/pull/144281
Similar to FindLastIV, add FindFirstIVSMin to support select (icmp(), x, y)
reductions where one of x or y is a decreasing induction, producing a SMin
reduction. It uses signed max as sentinel value.
PR: https://github.com/llvm/llvm-project/pull/140451
Currently FirstActiveLane is not handled correctly during
unrolling. This is currently causing mis-compiles when
vectorizing early-exit loops with interleaving forced.
This patch updates handling of FirstActiveLane to be analogous to
computing final reduction results: during unrolling, the created copies
for its original operand are added as additional operands, and
FirstActiveLane will always produce the index of the first active lane
across all unrolled iterations.
Note that some of the generated code is still incorrect, as we also need
to handle ExtractElement with FirstActiveLane operands. I will share
patches for those soon as well.
PR: https://github.com/llvm/llvm-project/pull/145394
Currently AnyOf is not handled correctly during unrolling. This is
currently causing mis-compiles when vectorizing early-exit loops with
interleaving forced (even though selectInterleaveCount will currently
only pick IC = 1, unless forced by the user).
This patch updates handling of AnyOf to be analogous to computing final
reduction results: during unrolling, the created copies for its original
operand are added as additional operands, and AnyOf will always produce
the reduced value across all unrolled iterations.
Note that the generated code is still incorrect, as we also need to
handle FirstActiveLane and ExtractElement with FirstActiveLane operands.
I will share patches for those soon as well.
PR: https://github.com/llvm/llvm-project/pull/145340
Explicitly unroll VPReplicateRecipes outside replicate regions by VF,
replacing them by VF single-scalar recipes. Extracts for operands are
added as needed and the scalar results are combined to a vector using a
new BuildVector VPInstruction.
It also adds a few folds to simplify unnecessary extracts/BuildVectors.
It also adds a BuildStructVector opcode for handling of calls that have
struct return types.
VPReplicateRecipe in replicate regions can will be unrolled as follow
up, turing non-single-scalar VPReplicateRecipes into 'abstract', i.e.
not executable.
PR: https://github.com/llvm/llvm-project/pull/142433
Add a new getNumOperandsForOpcode helper to determine the number of
operands from the opcode. For now, it is used to verify the number
operands at VPInstruction construction.
It returns -1 for a few opcodes where the number of operands cannot be
determined (GEP, Switch, PHI, Call).
This can also be used in a follow-up to determine if a VPInstruction is
masked based on the number of arguments.
PR: https://github.com/llvm/llvm-project/pull/142284
Similarly to VPWidenIntOrFpInductionRecipe, if we want to support it in
EVL tail folding we need to increment the induction by EVL steps instead
of VF*UF steps, but currently this is hard-wired in
VPWidenPointerInductionRecipe.
This adds an operand for the number of elements unrolled and plumbs it
through, so that we can swap it out in
VPlanTransforms::tryAddExplicitVectorLength further down the line.
The motivation of this PR is to make #115274 easier to implement, and
should allow us to add EVL support by just passing EVL to the VF
operand.
The current difficulty with widening IVs with EVL is that
VPWidenIntOrFpInductionRecipe generates its own backedge value. Since
it's a VPHeaderPHIRecipe the VF operand must be in the preheader, which
means we can't use the EVL since it's defined in the loop body.
The gist in this PR is to take the approach in #114305 and expand
VPWidenIntOrFpInductionRecipe into several recipes for the initial
value, phi and backedge value just before execution. I.e. this example:
```
vector.ph:
Successor(s): vector loop
<x1> vector loop: {
vector.body:
WIDEN-INDUCTION %i = phi %start, %step, %vf
...
EMIT branch-on-count ...
No successors
}
```
gets expanded to:
```
vector.ph:
...
vp<%induction.start> = ...
vp<%induction.increment> = ...
Successor(s): vector loop
<x1> vector loop: {
vector.body:
ir<%i> = WIDEN-PHI vp<%induction.start>, vp<%vec.ind.next>
...
vp<%vec.ind.next> = add ir<%i>, vp<%induction.increment>
EMIT branch-on-count ...
No successors
}
```
This allows us to a value defined in the loop in the backedge value, and
also means we can just reuse the existing backedge fixups in
VPlan::execute without having to specially handle it ourselves.
After this #115274 should just become a matter of setting the VF operand
to EVL (and building the increment step in the loop body, not the
preheader).
This reverts commit 0604dc199c019b23746f4a54885ba0c75569cdae.
The recommitted version addresses post-commit comments and adjusts the
place the branch weights are added. It now runs before VPlans are optimized
for VF and UF, which may remove the vector loop region, causing a crash
trying to get the middle block after that. Test case added in
72f99b75afc12bb.
Original message:
Manage branch weights for the BranchOnCond in the middle block in VPlan.
This requires updating VPInstruction to inherit from VPIRMetadata, which
in general makes sense as there are a number of opcodes that could take
metadata.
There are other branches (part of the skeleton) that also need branch
weights adding.
PR: https://github.com/llvm/llvm-project/pull/143035
This caused assertion failures:
llvm/lib/Transforms/Vectorize/VPlan.h:4021:
llvm::VPBasicBlock* llvm::VPlan::getMiddleBlock():
Assertion `LoopRegion && "cannot call the function after vector loop region has been removed"' failed.
See comment on the PR.
> Manage branch weights for the BranchOnCond in the middle block in VPlan.
> This requires updating VPInstruction to inherit from VPIRMetadata, which
> in general makes sense as there are a number of opcodes that could take
> metadata.
>
> There are other branches (part of the skeleton) that also need branch
> weights adding.
>
> PR: https://github.com/llvm/llvm-project/pull/143035
This reverts commit db8d34db26e9ea92c08d6e813eca9cce40c48478.
Manage branch weights for the BranchOnCond in the middle block in VPlan.
This requires updating VPInstruction to inherit from VPIRMetadata, which
in general makes sense as there are a number of opcodes that could take
metadata.
There are other branches (part of the skeleton) that also need branch
weights adding.
PR: https://github.com/llvm/llvm-project/pull/143035
Following the work in PR #107279, this patch applies the annotative
DebugLocs, which indicate that a particular instruction is intentionally
missing a location for a given reason, to existing sites in the compiler
where their conditions apply. This is NFC in ordinary LLVM builds (each
function `DebugLoc::getFoo()` is inlined as `DebugLoc()`), but marks the
instruction in coverage-tracking builds so that it will be ignored by
Debugify, allowing only real errors to be reported. From a developer
standpoint, it also communicates the intentionality and reason for a
missing DebugLoc.
Some notes for reviewers:
- The difference between `I->dropLocation()` and
`I->setDebugLoc(DebugLoc::getDropped())` is that the former _may_ decide
to keep some debug info alive, while the latter will always be empty; in
this patch, I always used the latter (even if the former could
technically be correct), because the former could result in some
(barely) different output, and I'd prefer to keep this patch purely NFC.
- I've generally documented the uses of `DebugLoc::getUnknown()`, with
the exception of the vectorizers - in summary, they are a huge cause of
dropped source locations, and I don't have the time or the domain
knowledge currently to solve that, so I've plastered it all over them as
a form of "fixme".
Add a new VPInstruction::ReductionStartVector opcode to create the start
values for wide reductions. This more accurately models the start value
creation in VPlan and simplifies VPReductionPHIRecipe::execute. Down the
line it also allows removing VPReductionPHIRecipe::RdxDesc.
PR: https://github.com/llvm/llvm-project/pull/142290
Move code to get the index of a predecessor and successor to helpers in
VPBlockBase, to avoid duplication and enable future reuse.
Split off from https://github.com/llvm/llvm-project/pull/140409.
