Similar to the MQPR register class as the MVE equivalent to QPR, this
adds MQQPR and MQQQQPR register classes for the MVE equivalents of QQPR
and QQQQPR registers. The MVE MQPR seemed have worked out quite well,
and adding MQQPR and MQQQQPR allows us to a little more accurately
specify the number of registers, calculating register pressure limits a
little better.
Differential Revision: https://reviews.llvm.org/D107463
Follow-up to D107068, attempt to fold nested concat_vectors/undefs, as long as both the vector and inner subvector types are legal.
This exposed the same issue in ARM's MVE LowerCONCAT_VECTORS_i1 (raised as PR51365) and AArch64's performConcatVectorsCombine which both assumed concat_vectors only took 2 subvector operands.
Differential Revision: https://reviews.llvm.org/D107597
Given a constant operand, the MVE and DAGCombine combines could fight,
each redistributing in the opposite order. Add a guard to the MVE
vecreduce distribution to prevent that.
D107068 fixed the same problem on aarch64 but the arm variant wasn't exposed in existing test coverage.
I've copied the arm64-neon-copy tests (and stripped the intrinsic test from it) for testing on arm neon builds as well.
This distributes reductions based on the relative offset of loads, if
one is found from their operands. Given chains of reductions this will
then sort them in ascending load order, which in turn can help simple
prefetches latch on to increasing strides more easily.
Differential Revision: https://reviews.llvm.org/D106569
This adds a combine for adds of reductions, distributing them so that
they occur sequentially to enable better use of accumulating VADDVA
instructions. It combines:
add(X, add(vecreduce(Y), vecreduce(Z))) ->
add(add(X, vecreduce(Y)), vecreduce(Z))
and
add(add(A, reduce(B)), add(C, reduce(D))) ->
add(add(add(A, C), reduce(B)), reduce(D))
These together distribute the add's so that more reductions can be
selected to VADDVA.
Differential Revision: https://reviews.llvm.org/D106532
Under MVE we can use VADDV/VADDVA's to perform integer add reductions,
so it can be beneficial to use more reductions than summing subvectors
and reducing once. Especially for VMLAV/VMLAVA the mul can be
incorporated into the reduction, producing less instructions.
Some of the test cases currently get larger due to extra integer adds,
but will be improved in a followup patch.
Differential Revision: https://reviews.llvm.org/D106531
This removes the promotion of NEON AND, OR and XOR nodes to v2i32/v4i32,
treating them the same as the AArch64 and MVE backends where we just add
the relevant patterns for each legal type. This prevents a lot of
bitcasts from being added to the DAG, which have the potential to make
optimizations more difficult. It does mean adding extra patterns, and
some codegen can change due to the types now being legal, not promoted.
Differential Revision: https://reviews.llvm.org/D105588
This relaxes the VMLAV and VADDV reduction recognition code to handle
smaller than legal types, extending them as needed. That was already
handled for some reductions, this extends it to more types in a more
generic way. If a smaller than legal value is found it is extended to
the legal type as needed.
Differential Revision: https://reviews.llvm.org/D106051
We have a DAG combine for recognizing the sequence of nodes that make up
an MVE VQDMULH, but only currently handles specifically legal types.
This patch expands that to other power-2 vector types. For smaller than
legal types this means any_extending the type and casting it to a legal
type, using a VQDMULH where we only use some of the lanes. The result is
sign extended back to the original type, to properly set the invalid
lanes. Larger than legal types are split into chunks with extracts and
concat back together.
Differential Revision: https://reviews.llvm.org/D105814
For i64 reductions we currently try and convert add(VMLALV(X, Y), B) to
VMLALVA(B, X, Y), incorporating the addition into the VMLALVA. If we
have an add of an existing VMLALVA, this patch pushes the add up above
the VMLALVA so that it may potentially be simplified further, for
example being folded into another VMLALV.
Differential Revision: https://reviews.llvm.org/D105686
MVE does not have a VMLALV instruction that can perform v16i8 -> i64
reductions, like it does for v8i16->i64 and v4i32->i64 reductions. That
means that the pattern to create them will be spilt up by type
legalization, creating a lot of instructions.
This extends the patterns for matching i64 reductions a little to handle
the v16i8->i64 case. We need to turn them into a pair of v8i16->i64
VMLALVs that each perform half of the reduction and are summed together
(so the later is a VMLALVA). The order of the lanes does not matter for
the reduction so we generate a MVEEXT for the extension, that will
either be folded into a extending load or can be optimized to a
VREV/VMOVL. Some of the resulting codegen isn't optimal, but will be
improved in a later patch.
Differential Revision: https://reviews.llvm.org/D105680
Similar to D91921 (and D104515) this introduces two MVESEXT and MVEZEXT
nodes that larger-than-legal sext and zext are lowered to. These either
get optimized away or end up becoming a series of stack loads/store, in
order to perform the extending whilst keeping the order of the lanes
correct. They are generated from v8i16->v8i32, v16i8->v16i16 and
v16i8->v16i32 extends, potentially with a intermediate extend for the
larger v16i8->v16i32 extend. A number of combines have been added for
obvious cases that come up in tests, notably MVEEXT of shuffles. More
may be needed in the future, but this seems to cover most of the cases
that come up in the tests.
Differential Revision: https://reviews.llvm.org/D105090
D104868 removed an (incorrect) fold for distributing BFI instructions in
a chain, combining them into a single instruction. BFIs like that are
hard to test, as the patterns are often destroyed before they become
BFIs. But it can come up in places, with chains of BFIs that can be
combined.
This patch adds a replacement, which reassociates BFI instructions with
non-overlapping insertion masks so that low bits are inserted first.
This can end up sorting the nodes so that adjacent inserts are next to
one another, allowing the existing folds to combine into a single BFI.
Differential Revision: https://reviews.llvm.org/D105096
This adds a small fold for extract (ARM_BUILD_VECTOR) to fold to the
original node. This can help simplify the resulting codegen in some
cases.
Differential Revision: https://reviews.llvm.org/D104860
This adds another small fold for extract of a vdup, between a i32 and a
f32, converting to a BITCAST. This allows some extra folding to happen,
simplifying the resulting code.
Differential Revision: https://reviews.llvm.org/D104857
The MVETRUNC node truncates two wide vectors to a single vector with
narrower elements. This is usually lowered to a series of extract/insert
elements, going via GPR registers. This patch changes that to instead
use a pair of truncating stores and a stack reload. This cuts down the
number of instructions at the expense of some stack space.
Differential Revision: https://reviews.llvm.org/D104515
Currently, when encountering store(trunc(..)) where the trunc is double
a legal vector lenth in MVE, we spilt the node into two different stores
each performing half of the trunc from the wider type. This works well
for efficiently lowering wider than legal types, else the trunc becomes
a series of individual lane moves. Unfortunately this splitting is
currently one of the first combines attempted, so can happen before any
other combines which might be more preferable.
This patch instead introduces the concept of a MVETRUNC ISel node that
the trunk is initially lowered to, to keep it intact as a single item as
opposed to splitting it up. This allows us to push the store(trunc(..))
combine later, allowing other optimisations to potentially happen on the
trunc first. The store(trunc(..)) splitting can then be done later in
the legalisation period if needed, or else fall back to a buildvector as
before.
This can also be used in the future to lower to loads/stores, as opposed
to the more expensive lane extracts/inserts. Some extra combines are
added to keep all the existing tests happy.
Differential Revision: https://reviews.llvm.org/D91921
For a bfi chain like:
a = bfi input, x, y
b = bfi a, x', y'
The previous code was RAUW'ing a with x, mutating the second 'b' bfi, and when
SelectionDAG's CSE code ended up deleting it unexpectedly, bad things happend.
There's no need to RAUW in this case because we can just return our newly
created replacement BFI node. It also looked incorrect because it didn't account
for other users of the 'a' bfi.
Since it seems that chains of more than 2 BFI nodes are hard/impossible to
produce without this combine kicking in at some point, I've removed that
functionality since it had no test coverage.
rdar://79095399
Differential Revision: https://reviews.llvm.org/D104868
This is a mechanical change. This actually also renames the
similarly named methods in the SmallString class, however these
methods don't seem to be used outside of the llvm subproject, so
this doesn't break building of the rest of the monorepo.
Since this method can apply to cmpxchg operations, make sure it's clear
what value we're actually retrieving. This will help ensure we don't
accidentally ignore the failure ordering of cmpxchg in the future.
We could potentially introduce a getOrdering() method on AtomicSDNode
that asserts the operation isn't cmpxchg, but not sure that's
worthwhile.
Differential Revision: https://reviews.llvm.org/D103338
This only applies to FastIsel. GlobalIsel seems to sidestep
the issue.
This fixes https://bugs.llvm.org/show_bug.cgi?id=46996
One of the things we do in llvm is decide if a type needs
consecutive registers. Previously, we just checked if it
was an array or not.
(plus an SVE specific check that is not changing here)
This causes some confusion when you arbitrary IR like:
```
%T1 = type { double, i1 };
define [ 1 x %T1 ] @foo() {
entry:
ret [ 1 x %T1 ] zeroinitializer
}
```
We see it is an array so we call CC_AArch64_Custom_Block
which bails out when it sees the i1, a type we don't want
to put into a block.
This leaves the location of the double in some kind of
intermediate state and leads to odd codegen. Which then crashes
the backend because it doesn't know how to implement
what it's been asked for.
You get this:
```
renamable $d0 = FMOVD0
$w0 = COPY killed renamable $d0
```
Rather than this:
```
$d0 = FMOVD0
$w0 = COPY $wzr
```
The backend knows how to copy 64 bit to 64 bit registers,
but not 64 to 32. It can certainly be taught how but the real
issue seems to be us even trying to assign a register block
in the first place.
This change makes the logic of
AArch64TargetLowering::functionArgumentNeedsConsecutiveRegisters
a bit more in depth. If we find an array, also check that all the
nested aggregates in that array have a single member type.
Then CC_AArch64_Custom_Block's assumption of a type that looks
like [ N x type ] will be valid and we get the expected codegen.
New tests have been added to exercise these situations. Note that
some of the output is not ABI compliant. The aim of this change is
to simply handle these situations and not to make our processing
of arbitrary IR ABI compliant.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D104123
Under MVE v4f32 and v8f16 vectors should be using v4i1/v8i1 predicates
for the setcc result type, as they have predicated registers for those
types. Setting this correctly prevents some inefficient optimizations
from happening.
Re-applying this patch after bots failures. Should be fine now.
The function __multi3() is undefined on 32-bit ARM, so a call to it should
never be emitted. Instead, plain instructions need to be generated to
perform 128-bit multiplications.
Differential Revision: https://reviews.llvm.org/D103906
The function __multi3() is undefined on 32-bit ARM, so a call to it
should never be emitted. Instead, plain instructions need to be
generated to perform 128-bit multiplications.
Differential Revision: https://reviews.llvm.org/D103906
If we cannot otherwise use a VMOVimm/VMOVFPimm/VMVNimm, fall back to
producing a VDUP(const) as opposed to a constant pool load. This will at
least be smaller codesize and can allow the VDUP to be folded into other
instructions.
Differential Revision: https://reviews.llvm.org/D103808
Don't require a specific kind of IRBuilder for TargetLowering hooks.
This allows us to drop the IRBuilder.h include from TargetLowering.h.
Differential Revision: https://reviews.llvm.org/D103759
SwiftTailCC has a different set of requirements than the C calling convention
for a tail call. The exact argument sequence doesn't have to match, but fewer
ABI-affecting attributes are allowed.
Also make sure the musttail diagnostic triggers if a musttail call isn't
actually a tail call.
Now that vmulh can be selected, this adds the MVE patterns to make it
legal and generate instructions.
Differential Revision: https://reviews.llvm.org/D88011
This makes sure that the blocks created for lowering memcpy to loops end
up with branches, even if they fall through to the successor. Otherwise
IfCvt is getting confused with unanalyzable branches and creating
invalid block layouts.
The extra branches should be removed as the tail predicated loop is
finalized in almost all cases.
The trip count for a memcpy/memset will be n/16 rounded up to the
nearest integer. So (n+15)>>4. The old code was including a BIC too, to
clear one of the bits, which does not seem correct. This remove the
extra BIC.
Note that ideally this would never actually be generated, as in the
creation of a tail predicated loop we will DCE that setup code, letting
the WLSTP perform the trip count calculation. So this doesn't usually
come up in testing (and apparently the ARMLowOverheadLoops pass does not
do any sort of validation on the tripcount). Only if the generation of
the WLTP fails will it use the incorrect BIC instructions.
Differential Revision: https://reviews.llvm.org/D102629
Swift's new concurrency features are going to require guaranteed tail calls so
that they don't consume excessive amounts of stack space. This would normally
mean "tailcc", but there are also Swift-specific ABI desires that don't
naturally go along with "tailcc" so this adds another calling convention that's
the combination of "swiftcc" and "tailcc".
Support is added for AArch64 and X86 for now.
These pseudos are converted post-isel into t2WhileLoopStart and
t2LoopEnd/LoopDec instructions, which themselves are defined to clobber
CPSR. Doing the same with the MEMCPY nodes will make sure they are
scheduled correctly to not end up with incorrect uses.
Based on the same for AArch64: 4751cadcca
At -O0, the fast register allocator may insert spills between the ldrex and
strex instructions inserted by AtomicExpandPass when expanding atomicrmw
instructions in LL/SC loops. To avoid this, expand to cmpxchg loops and
therefore expand the cmpxchg pseudos after register allocation.
Required a tweak to ARMExpandPseudo::ExpandCMP_SWAP to use the 4-byte encoding
of UXT, since the pseudo instruction can be allocated a high register (R8-R15)
which the 2-byte encoding doesn't support. However, the 4-byte encodings
are not present for ARM v8-M Baseline. To enable this, two new pseudos are
added for Thumb which are only valid for v8mbase, tCMP_SWAP_8 and
tCMP_SWAP_16.
The previously committed attempt in D101164 had to be reverted due to runtime
failures in the test suites. Rather than spending time fixing that
implementation (adding another implementation of atomic operations and more
divergence between backends) I have chosen to follow the approach taken in
D101163.
Differential Revision: https://reviews.llvm.org/D101898
Depends on D101912
Arthur Eubanks