Widen the scope of memory operations that are allowed to be tail predicated
to include gathers and scatters, such that loops that are auto-vectorized
with the option -enable-arm-maskedgatscat (and actually end up containing
an MVE gather or scatter) can be tail predicated.
Differential Revision: https://reviews.llvm.org/D85138
When TTI was updated to use an explicit cost, TCK_CodeSize was used
although the default implicit cost would have been the hand-wavey
cost of size and latency. So, revert back to this behaviour. This is
not expected to have (much) impact on targets since most (all?) of
them return the same value for SizeAndLatency and CodeSize.
When optimising for size, the logic has been changed to query
CodeSize costs instead of SizeAndLatency.
This patch also adds a testing option in the unroller so that
OptSize thresholds can be specified.
Differential Revision: https://reviews.llvm.org/D85723
This pick ups the work on the overflow checks for get.active.lane.mask,
which ensure that it is safe to insert the VCTP intrinisc that enables
tail-predication. For a 2d auto-correlation kernel and its inner loop j:
M = Size - i;
for (j = 0; j < M; j++)
Sum += Input[j] * Input[j+i];
For this inner loop, the SCEV backedge taken count (BTC) expression is:
(-1 + (sext i16 %Size to i32)),+,-1}<nw><%for.body>
and LoopUtil cannotBeMaxInLoop couldn't calculate a bound on this, thus "BTC
cannot be max" could not be determined. So overflow behaviour had to be assumed
in the loop tripcount expression that uses the BTC. As a result
tail-predication had to be forced (with an option) for this case.
This change solves that by using ScalarEvolution's helper
getConstantMaxBackedgeTakenCount which is able to determine the range of BTC,
thus can determine it is safe, so that we no longer need to force tail-predication
as reflected in the changed test cases.
Differential Revision: https://reviews.llvm.org/D85737
Changes the Offset arguments to both functions from int64_t to TypeSize
& updates all uses of the functions to create the offset using TypeSize::Fixed()
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D85220
IT blocks with more than one instruction were performance deprecated in Armv8
but that doesn't mean we should follow that advise when optimising for size.
Differential Revision: https://reviews.llvm.org/D85638
This adds patterns for v16i16's vecreduce, using all the existing code
to go via an i32 VADDV/VMLAV and truncating the result.
Differential Revision: https://reviews.llvm.org/D85452
This formats some of the MVE patterns, and adds a missing
Predicates = [HasMVEInt] to some VRHADD patterns I noticed
as going through. Although I don't believe NEON would ever
use the patterns (as it would use ADDL and VSHRN instead)
they should ideally be predicated on having MVE instructions.
As with other targets, set the throughput cost of control-flow
instructions to free so that we don't miss out of vectorization
opportunities.
Differential Revision: https://reviews.llvm.org/D85283
Added patterns so that both SSAT and USAT instructions are generated with shifts. Added corresponding regression tests.
Differential Review: https://reviews.llvm.org/D85120
VPSEL has slightly different semantics under tail predication (it can
end up selecting from Qn, Qm and Qd). We do not model that at the moment
so they block tail predicated loops from being formed.
This just converts them into a predicated VMOV instead (via a VORR),
allowing tail predication to happen whilst still modelling the original
behaviour of the input.
Differential Revision: https://reviews.llvm.org/D85110
Fixes a regression caused by D82439, in which IT blocks were no longer being
generated when -Oz is present. This was due to the CPSR register being marked as
dead, while this case was not accounted for.
Differential Revision: https://reviews.llvm.org/D83667
This adds sign/zero extending scalar loads/stores to the MVE
instructions added in D77813, allowing us to create up more post-inc
instructions. These are comparatively simple, compared to LDR/STR (which
may be better turned into an LDRD/LDM), but still require some additions
over MVE instructions. Because there are i12 and i8 variants of the
offset loads/stores dealing with different signs, we may need to convert
an i12 address to a i8 negative instruction. t2LDRBi12 can also be
shrunk to a tLDRi under the right conditions, so we need to be careful
with codesize too.
Differential Revision: https://reviews.llvm.org/D78625
I've been looking at missed vectorizations in one codebase.
One particular thing that stands out is that some of the loops
reach vectorizer in a rather mangled form, with weird PHI's,
and some of the loops aren't even in a rotated form.
After taking a more detailed look, that happened because
the loop's headers were too big by then. It is evident that
SimplifyCFG's common code hoisting transform is at fault there,
because the pattern it handles is precisely the unrotated
loop basic block structure.
Surprizingly, `SimplifyCFGOpt::HoistThenElseCodeToIf()` is enabled
by default, and is always run, unlike it's friend, common code sinking
transform, `SinkCommonCodeFromPredecessors()`, which is not enabled
by default and is only run once very late in the pipeline.
I'm proposing to harmonize this, and disable common code hoisting
until //late// in pipeline. Definition of //late// may vary,
here currently i've picked the same one as for code sinking,
but i suppose we could enable it as soon as right after
loop rotation happens.
Experimentation shows that this does indeed unsurprizingly help,
more loops got rotated, although other issues remain elsewhere.
Now, this undoubtedly seriously shakes phase ordering.
This will undoubtedly be a mixed bag in terms of both compile- and
run- time performance, codesize. Since we no longer aggressively
hoist+deduplicate common code, we don't pay the price of said hoisting
(which wasn't big). That may allow more loops to be rotated,
so we pay that price. That, in turn, that may enable all the transforms
that require canonical (rotated) loop form, including but not limited to
vectorization, so we pay that too. And in general, no deduplication means
more [duplicate] instructions going through the optimizations. But there's still
late hoisting, some of them will be caught late.
As per benchmarks i've run {F12360204}, this is mostly within the noise,
there are some small improvements, some small regressions.
One big regression i saw i fixed in rG8d487668d09fb0e4e54f36207f07c1480ffabbfd, but i'm sure
this will expose many more pre-existing missed optimizations, as usual :S
llvm-compile-time-tracker.com thoughts on this:
http://llvm-compile-time-tracker.com/compare.php?from=e40315d2b4ed1e38962a8f33ff151693ed4ada63&to=c8289c0ecbf235da9fb0e3bc052e3c0d6bff5cf9&stat=instructions
* this does regress compile-time by +0.5% geomean (unsurprizingly)
* size impact varies; for ThinLTO it's actually an improvement
The largest fallout appears to be in GVN's load partial redundancy
elimination, it spends *much* more time in
`MemoryDependenceResults::getNonLocalPointerDependency()`.
Non-local `MemoryDependenceResults` is widely-known to be, uh, costly.
There does not appear to be a proper solution to this issue,
other than silencing the compile-time performance regression
by tuning cut-off thresholds in `MemoryDependenceResults`,
at the cost of potentially regressing run-time performance.
D84609 attempts to move in that direction, but the path is unclear
and is going to take some time.
If we look at stats before/after diffs, some excerpts:
* RawSpeed (the target) {F12360200}
* -14 (-73.68%) loops not rotated due to the header size (yay)
* -272 (-0.67%) `"Number of live out of a loop variables"` - good for vectorizer
* -3937 (-64.19%) common instructions hoisted
* +561 (+0.06%) x86 asm instructions
* -2 basic blocks
* +2418 (+0.11%) IR instructions
* vanilla test-suite + RawSpeed + darktable {F12360201}
* -36396 (-65.29%) common instructions hoisted
* +1676 (+0.02%) x86 asm instructions
* +662 (+0.06%) basic blocks
* +4395 (+0.04%) IR instructions
It is likely to be sub-optimal for when optimizing for code size,
so one might want to change tune pipeline by enabling sinking/hoisting
when optimizing for size.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D84108
This patch uses the feature added in D79162 to fix the cost of a
sext/zext of a masked load, or a trunc for a masked store.
Previously, those were considered cheap or even free, but it's
not the case as we cannot split the load in the same way we would for
normal loads.
This updates the costs to better reflect reality, and adds a test for it
in test/Analysis/CostModel/ARM/cast.ll.
It also adds a vectorizer test that showcases the improvement: in some
cases, the vectorizer will now choose a smaller VF when
tail-predication is enabled, which results in better codegen. (Because
if it were to use a higher VF in those cases, the code we see above
would be generated, and the vmovs would block tail-predication later in
the process, resulting in very poor codegen overall)
Original Patch by Pierre van Houtryve
Differential Revision: https://reviews.llvm.org/D79163
Currently, getCastInstrCost has limited information about the cast it's
rating, often just the opcode and types. Sometimes there is a context
instruction as well, but it isn't trustworthy: for instance, when the
vectorizer is rating a plan, it calls getCastInstrCost with the old
instructions when, in fact, it's trying to evaluate the cost of the
instruction post-vectorization. Thus, the current system can get the
cost of certain casts incorrect as the correct cost can vary greatly
based on the context in which it's used.
For example, if the vectorizer queries getCastInstrCost to evaluate the
cost of a sext(load) with tail predication enabled, getCastInstrCost
will think it's free most of the time, but it's not always free. On ARM
MVE, a VLD2 group cannot be extended like a normal VLDR can. Similar
situations can come up with how masked loads can be extended when being
split.
To fix that, this path adds a new parameter to getCastInstrCost to give
it a hint about the context of the cast. It adds a CastContextHint enum
which contains the type of the load/store being created by the
vectorizer - one for each of the types it can produce.
Original patch by Pierre van Houtryve
Differential Revision: https://reviews.llvm.org/D79162
Optimize some specific immediates selection by materializing them with sub/mvn
instructions as opposed to loading them from the constant pool.
Patch by Ben Shi, powerman1st@163.com.
Differential Revision: https://reviews.llvm.org/D83745
A patch following up on the introduction of pointer induction variables, adding
a preprocessing step to the address optimisation in the MVEGatherScatterLowering
pass. If the getelementpointer that is the address is itself using a
getelementpointer as base, they will be merged into one by summing up the
offsets, after checking that this will not cause an overflow (this can be
repeated recursively).
Differential Revision: https://reviews.llvm.org/D84027
Many Thumb1 instructions are defined to set CPSR if executed outside an IT
block, but leave it alone from inside one. In MachineIR this is represented by
whether an optional register is CPSR or NoReg (0), and affects how the
instructions are printed.
This sets the instruction to the appropriate form during if-conversion.
Added extra patterns to VABD instruction so it is selected in place of VSUB and VABS. Added corresponding regression test too.
Differential Revision: https://reviews.llvm.org/D84500
Similar to 8fa824d7a3 but this time for MLA patterns, this selects
predicated vmlav/vmlava/vmlalv/vmlava instructions from
vecreduce.add(select(p, mul(x, y), 0)) nodes.
Differential Revision: https://reviews.llvm.org/D84102
There's no reason to involve the hassle of a virtual method targets
have to override for a simple boolean.
Not sure exactly what's going on with Mips, but it seems to define its
own totally separate handler classes.
Given a vecreduce.add(select(p, x, 0)), we can convert that to a
predicated vaddv, as the else value for the select is the identity
value, a zero. That is what this patch does for the vaddv, vaddva,
vaddlv and vaddlva instructions, copying the existing patterns to also
handle predication through a select.
Differential Revision: https://reviews.llvm.org/D84101
For a long time, the InstCombine pass handled target specific
intrinsics. Having target specific code in general passes was noted as
an area for improvement for a long time.
D81728 moves most target specific code out of the InstCombine pass.
Applying the target specific combinations in an extra pass would
probably result in inferior optimizations compared to the current
fixed-point iteration, therefore the InstCombine pass resorts to newly
introduced functions in the TargetTransformInfo when it encounters
unknown intrinsics.
The patch should not have any effect on generated code (under the
assumption that code never uses intrinsics from a foreign target).
This introduces three new functions:
TargetTransformInfo::instCombineIntrinsic
TargetTransformInfo::simplifyDemandedUseBitsIntrinsic
TargetTransformInfo::simplifyDemandedVectorEltsIntrinsic
A few target specific parts are left in the InstCombine folder, where
it makes sense to share code. The largest left-over part in
InstCombineCalls.cpp is the code shared between arm and aarch64.
This allows to move about 3000 lines out from InstCombine to the targets.
Differential Revision: https://reviews.llvm.org/D81728
This is very similar to 243970d03cace2, but handling a slightly
different form of predicated operations. When starting with a pattern of
the form select(p, BinOp(x, y), x), Instcombine will often transform
this to BinOp(x, select(p, y, 0)), where 0 is the identity value of the
binop (0 for adds/subs, 1 for muls, -1 for ands etc). This adds the
patterns that transforms those back into predicated binary operations.
There is also a very minor adjustment to tablegen null_frag in here, to
allow it to also be recognized as a PatLeaf node, so that it can be used
in MVE_TwoOpPattern to easily exclude the cases where we do not need the
alternate transform.
Differential Revision: https://reviews.llvm.org/D84091
Most MVE instructions can be predicated to fold a select into the
instruction, using the predicate and the selects else as a passthough.
This adds tablegen patterns for most two operand instructions using the
newly added TwoOpPattern from 1030e82598.
Differential Revision: https://reviews.llvm.org/D83222
Summary:
[Thumb] set code alignment for 16-bit load from constant pool
LLVM miscompiles this code when compiling for a target with v8.2-A FP16 and the Thumb ISA at -O0:
extern void bar(__fp16 P5);
int main() {
__fp16 P5 = 1.96875;
bar(P5);
}
The code section containing main has 2 byte alignment.
It needs to have 4 byte alignment,
because the load literal instruction has an offset from the
load address with the low 2 bits zeroed.
I do not include a test case in this check-in.
llc and llvm-mc do not exhibit this bug. They do not set code section alignment
in the same manner as clang.
Reviewers: dnsampaio
Reviewed By: dnsampaio
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D84169
Summary:
This fixes Bugzilla #46616 in which it was reported
that "tbb [pc, r0]" was marked as SoftFail
(aka unpredictable) incorrectly.
Expected behaviour is:
* ARMv8 is required to use sp as rn or rm
(tbb/tbh only have a Thumb encoding so using Arm mode
is not an option)
* If rm is the pc then the instruction is always
unpredictable
Some of this was implemented already and this fixes the
rest. Added tests cover the new and pre-existing handling.
Reviewers: ostannard
Reviewed By: ostannard
Subscribers: kristof.beyls, hiraditya, danielkiss, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D84227
This commons out a chunk of the different two operand MVE patterns into
a single helper multidef. Or technically two multidef patterns so that
the Dup qr patterns can also get the same treatment. This is most of the
two address instructions that we have some codegen pattern for (not ones
that we select purely from intrinsics). It does not include shifts,
which are more spread out and will need some extra work to be given the
same treatment.
Differential Revision: https://reviews.llvm.org/D83219
These extra vcvt instructions were missed from 74ca67c109 because they
live in a different Domain, but should be treated in the same way.
Differential Revision: https://reviews.llvm.org/D83204
As far as I can tell, it should not be necessary for VCTP to be
unpredictable in tail predicated loops. Either it has a a valid loop
counter as a operand which will naturally keep it in the right loop, or
it doesn't and it won't be converted to a tail predicated loop. Not
marking it as having side effects allows it to be scheduled more cleanly
for cases where it is not expected to become a tail predicate loop.
Differential Revision: https://reviews.llvm.org/D83907
When the byref attribute is added, there will need to be two similar
functions for the existing cases which have an associate value copy,
and byref which does not. Most, but not all of the existing uses will
use the existing version.
The associated size function added by D82679 also needs to
contextually differ, and will help eliminate a few places still
relying on pointee element types.
This reverts commit 1067d3e176,
which reverted commit b2018198c3,
because it introduced a Dependency Cycle between Transforms/Scalar and
Transforms/Utils.
So let's just move SimplifyCFGOptions.h into Utils/, thus avoiding
the cycle.
Vector bitwise selects are matched by pseudo VBSP instruction
and expanded to VBSL/VBIT/VBIF after register allocation
depend on operands registers to minimize extra copies.
This adds a peephole optimisation to turn a t2MOVccr that could not be
folded into any other instruction into a CSEL on 8.1-m. The t2MOVccr
would usually be expanded into a conditional mov, that becomes an IT;
MOV pair. We can instead generate a CSEL instruction, which can
potentially be smaller and allows better register allocation freedom,
which can help reduce codesize. Performance is more variable and may
depend on the micrarchitecture details, but initial results look good.
If we need to control this per-cpu, we can add a subtarget feature as we
need it.
Original patch by David Penry.
Differential Revision: https://reviews.llvm.org/D83566
This reverts commit b2018198c3.
This commit introduced a Dependency Cycle between Transforms/Scalar and
Transforms/Utils. Transforms/Scalar already depends on Transforms/Utils,
so if SimplifyCFGOptions.h is moved to Scalar, and Utils/Local.h still
depends on it, we have a cycle.
Taking so many parameters is simply unmaintainable.
We don't want to include the entire llvm/Transforms/Utils/Local.h into
llvm/Transforms/Scalar.h so i've split SimplifyCFGOptions into
it's own header.
If a vector body has live-out values, it is probably a reduction, which needs a
final reduction step after the loop. MVE has a VADDV instruction to reduce
integer vectors, but doesn't have an equivalent one for float vectors. A
live-out value that is not recognised as reduction later in the optimisation
pipeline will result in the tail-predicated loop to be reverted to a
non-predicated loop and this is very expensive, i.e. it has a significant
performance impact, which is what we hope to avoid with fine tuning the ARM TTI
hook preferPredicateOverEpilogue implementation.
Differential Revision: https://reviews.llvm.org/D82953
This refactors option -disable-mve-tail-predication to take different arguments
so that we have 1 option to control tail-predication rather than several
different ones.
This is also a prep step for D82953, in which we want to reject reductions
unless that is requested with this option.
Differential Revision: https://reviews.llvm.org/D83133
Summary:
This patch separates the peeling specific parameters from the UnrollingPreferences,
and creates a new struct called PeelingPreferences. Functions which used the
UnrollingPreferences struct for peeling have been updated to use the PeelingPreferences struct.
Author: sidbav (Sidharth Baveja)
Reviewers: Whitney (Whitney Tsang), Meinersbur (Michael Kruse), skatkov (Serguei Katkov), ashlykov (Arkady Shlykov), bogner (Justin Bogner), hfinkel (Hal Finkel), anhtuyen (Anh Tuyen Tran), nikic (Nikita Popov)
Reviewed By: Meinersbur (Michael Kruse)
Subscribers: fhahn (Florian Hahn), hiraditya (Aditya Kumar), llvm-commits, LLVM
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D80580
This patch upstreams support for the Arm-v8 Cortex-A78 and Cortex-X1
processors for AArch64 and ARM.
In detail:
- Adding cortex-a78 and cortex-x1 as cpu options for aarch64 and arm targets in clang
- Adding Cortex-A78 and Cortex-X1 CPU names and ProcessorModels in llvm
details of the CPU can be found here:
https://www.arm.com/products/cortex-xhttps://www.arm.com/products/silicon-ip-cpu/cortex-a/cortex-a78
The following people contributed to this patch:
- Luke Geeson
- Mikhail Maltsev
Reviewers: t.p.northover, dmgreen
Reviewed By: dmgreen
Subscribers: dmgreen, kristof.beyls, hiraditya, danielkiss, cfe-commits,
llvm-commits, miyuki
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D83206
This adjusts the MVE fp16 cost model, similar to how we already do for
integer casts. It uses the base cost of 1 per cvt for most fp extend /
truncates, but adjusts it for loads and stores where we know that a
extending load has been used to get the load into the correct lane, and
only an MVE VCVTB is then needed.
Differential Revision: https://reviews.llvm.org/D81813
This adds some default costs for fp extends and truncates, generally
costing them as 1 per lane. If the type is not legal then the cost will
include a call to an __aeabi_ function.
Some NEON code is also adjusted to make sure it applies to the expected
types, now that fp16 is a more common thing.
Differential Revision: https://reviews.llvm.org/D82458
This expands the existing extend costs with a few extras for larger
types than legal, which will usually be split under MVE. It also adds
trunk support for the same thing. These should not have a large effect
on many things, but makes the costs explicit and keeps a certain balance
between the trunks and extends.
Differential Revision: https://reviews.llvm.org/D82457
This alters getMemoryOpCost to use the Base TargetTransformInfo version
that includes some additional checks for whether extending loads are
legal. This will generally have the effect of making <2 x ..> and some
<4 x ..> loads/stores more expensive, which in turn should help favour
larger vector factors.
Notably it alters the cost of a <4 x half>, which with the current
codegen will be expensive if it is not extended.
Differential Revision: https://reviews.llvm.org/D82456
Whether an instruction is deemed to have side effects in determined by
whether it has a tblgen pattern that emits a single instruction.
Because of the way a lot of the the vcvt instructions are specified
either in dagtodag code or with patterns that emit multiple
instructions, they don't get marked as not having side effects.
This just marks them as not having side effects manually. It can help
especially with instruction scheduling, to not create artificial
barriers, but one of these tests also managed to produce fewer
instructions.
Differential Revision: https://reviews.llvm.org/D81639
This patch upstreams support for the Arm-v8 Cortex-A77
processor for AArch64 and ARM.
In detail:
- Adding cortex-a77 as a cpu option for aarch64 and arm targets in clang
- Cortex-A77 CPU name and ProcessorModel in llvm
details of the CPU can be found here:
https://www.arm.com/products/silicon-ip-cpu/cortex-a/cortex-a77
and a similar submission to GCC can be found here:
e0664b7a63
The following people contributed to this patch:
- Luke Geeson
- Mikhail Maltsev
Reviewers: t.p.northover, dmgreen, ostannard, SjoerdMeijer
Reviewed By: dmgreen
Subscribers: dmgreen, kristof.beyls, hiraditya, danielkiss, cfe-commits,
llvm-commits, miyuki
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D82887
Move the Thumb2SizeReduce pass to before IfConversion when optimising
for minimal code size.
Running the Thumb2SizeReduction pass before IfConversionallows T1
instructions to propagate to the final output, rather than the
ifConverter modifying T2 instructions and preventing them from being
reduced later.
This change does introduce a regression regarding execution time, so
it's only applied when optimising for size.
Running the LLVM Test Suite with this change produces a geomean
difference of -0.1% for the size..text metric.
Differential Revision: https://reviews.llvm.org/D82439
Before this instruction supported output values, it fit fairly
naturally as a terminator. However, being a terminator while also
supporting outputs causes some trouble, as the physreg->vreg COPY
operations cannot be in the same block.
Modeling it as a non-terminator allows it to be handled the same way
as invoke is handled already.
Most of the changes here were created by auditing all the existing
users of MachineBasicBlock::isEHPad() and
MachineBasicBlock::hasEHPadSuccessor(), and adding calls to
isInlineAsmBrIndirectTarget or mayHaveInlineAsmBr, as appropriate.
Reviewed By: nickdesaulniers, void
Differential Revision: https://reviews.llvm.org/D79794
While validating live-out values, record instructions that look like
a reduction. This will comprise of a vector op (for now only vadd),
a vorr (vmov) which store the previous value of vadd and then a vpsel
in the exit block which is predicated upon a vctp. This vctp will
combine the last two iterations using the vmov and vadd into a vector
which can then be consumed by a vaddv.
Once we have determined that it's safe to perform tail-predication,
we need to change this sequence of instructions so that the
predication doesn't produce incorrect code. This involves changing
the register allocation of the vadd so it updates itself and the
predication on the final iteration will not update the falsely
predicated lanes. This mimics what the vmov, vctp and vpsel do and
so we then don't need any of those instructions.
Differential Revision: https://reviews.llvm.org/D75533
After the rewrite of this pass (D79175) I missed one thing: the inserted VCTP
intrinsic can be cloned to exit blocks if there are instructions present in it
that perform the same operation, but this wasn't triggering anymore. However,
it turns out that for handling reductions, see D75533, it's actually easier not
not to have the VCTP in exit blocks, so this removes that code.
This was possible because it turned out that some other code that depended on
this, rematerialization of the trip count enabling more dead code removal
later, wasn't doing much anymore due to more aggressive dead code removal that
was added to the low-overhead loops pass.
Differential Revision: https://reviews.llvm.org/D82773
This patch stops the trunc, rint, round, floor and ceil intrinsics from blocking tail predication.
Differential Revision: https://reviews.llvm.org/D82553
MVE has native reductions for integer add and min/max. The others need
to be expanded to a series of extract's and scalar operators to reduce
the vector into a single scalar. The default codegen for that expands
the reduction into a series of in-order operations.
This modifies that to something more suitable for MVE. The basic idea is
to use vector operations until there are 4 remaining items then switch
to pairwise operations. For example a v8f16 fadd reduction would become:
Y = VREV X
Z = ADD(X, Y)
z0 = Z[0] + Z[1]
z1 = Z[2] + Z[3]
return z0 + z1
The awkwardness (there is always some) comes in from something like a
v4f16, which is first legalized by adding identity values to the extra
lanes of the reduction, and which can then not be optimized away through
the vrev; fadd combo, the inserts remain. I've made sure they custom
lower so that we can produce the pairwise additions before the extra
values are added.
Differential Revision: https://reviews.llvm.org/D81397
Pre-commit for D82257, this adds a DemandedElts arg to ShrinkDemandedConstant/targetShrinkDemandedConstant which will allow future patches to (optionally) add vector support.
Similar to the recent patch for fpext, this adds vcvtb and vcvtt with
insert into vector instruction selection patterns for fptruncs. This
helps clear up a lot of register shuffling that we would otherwise do.
Differential Revision: https://reviews.llvm.org/D81637
We current extract and convert from a top lane of a f16 vector using a
VMOVX;VCVTB pair. We can simplify that to use a single VCVTT. The
pattern is mostly copied from a vector extract pattern, but produces a
VCVTTHS f32 directly.
This had to move some code around so that ARMInstrVFP had access to the
required pattern frags that were previously part of ARMInstrNEON.
Differential Revision: https://reviews.llvm.org/D81556
This extends PerformSplittingToWideningLoad to also handle FP_Ext, as
well as sign and zero extends. It uses an integer extending load
followed by a VCVTL on the bottom lanes to efficiently perform an fpext
on a smaller than legal type.
The existing code had to be rewritten a little to not just split the
node in two and let legalization handle it from there, but to actually
split into legal chunks.
Differential Revision: https://reviews.llvm.org/D81340
This adds code to lower f16 to f32 fp_exts's using an MVE VCVT
instructions, similar to a recent similar patch for fp_trunc. Again it
goes through the lowering of a BUILD_VECTOR, but is slightly simpler
only having to deal with interleaved indices. It adds a VCVTL node to
lower to, similar to VCVTN.
Differential Revision: https://reviews.llvm.org/D81339
This splits MVE vector stores of a fp_trunc in the same way that we do
for standard trunc's. It extends PerformSplittingToNarrowingStores to
handle fp_round, splitting the store into pieces and adding a VCVTNb to
perform the actual fp_round. The actual store is then converted to an
integer store so that it can truncate bottom lanes of the result.
Differential Revision: https://reviews.llvm.org/D81141
This adds code to lower f32 to f16 fp_trunc's using a pair of MVE VCVT
instructions. Due to v4f16 not being legal, fp_round are often split up
fairly early. So this reconstructs the vcvt's from a buildvector of
fp_rounds from two vector inputs. Something like:
BUILDVECTOR(FP_ROUND(EXTRACT_ELT(X, 0),
FP_ROUND(EXTRACT_ELT(Y, 0),
FP_ROUND(EXTRACT_ELT(X, 1),
FP_ROUND(EXTRACT_ELT(Y, 1), ...)
It adds a VCVTN node to handle this, which like VMOVN or VQMOVN lowers
into the top/bottom lanes of an MVE instruction.
Differential Revision: https://reviews.llvm.org/D81139
The main interface has been migrated to Align already but a few backends where broadening the type from Align to MaybeAlign.
This patch makes sure all implementations conform to the public API.
Differential Revision: https://reviews.llvm.org/D82465
The ARM ARM considers p10/p11 valid arguments for MCR/MRC instructions.
MRC instructions with p10 arguments are also used in kernel code which
is shared for different architectures. Turn usage of p10/p11 to warnings
for ARMv7/ARMv8-M.
Reviewers: rengolin, olista01, t.p.northover, efriedma, psmith, simon_tatham
Reviewed By: simon_tatham
Subscribers: hiraditya, danielkiss, jcai19, tpimh, nickdesaulniers, peter.smith, javed.absar, kristof.beyls, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59733
Summary:
Get back `const` partially lost in one of recent changes.
Additionally specify explicit qualifiers in few places.
Reviewers: samparker
Reviewed By: samparker
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82383
Summary:
This change permits scalar bfloats to be loaded, stored, moved and
used as function call arguments and return values, whenever the bf16
feature is supported by the subtarget.
Previously that was only supported in the presence of the fullfp16
feature, because the code generation strategy depended on instructions
from that extension. This change adds alternative code generation
strategies so that those operations can be done even without fullfp16.
The strategy for loads and stores is to replace VLDRH/VSTRH with
integer LDRH/STRH plus a move between register classes. I've written
isel patterns for those, conditional on //not// having the fullfp16
feature (so that in the fullfp16 case, the existing patterns will
still be used).
For function arguments and returns, instead of writing isel patterns
to match `VMOVhr` and `VMOVrh`, I've avoided generating those SDNodes
in the first place, by factoring out the code that constructs them
into helper functions `MoveToHPR` and `MoveFromHPR` which have a
fallback for non-fullfp16 subtargets.
The current output code is not especially pretty: in the new test file
you can see unnecessary store/load pairs implementing no-op bitcasts,
and lots of pointless moves back and forth between FP registers and
GPRs. But it at least works, which is an improvement on the previous
situation.
Reviewers: dmgreen, SjoerdMeijer, stuij, chill, miyuki, labrinea
Reviewed By: dmgreen, labrinea
Subscribers: labrinea, kristof.beyls, hiraditya, danielkiss, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D82372
Implement them on top of sdiv/udiv, similar to what we do for integer
types.
Potential future work: implementing i8/i16 srem/urem, optimizations for
constant divisors, optimizing the mul+sub to mls.
Differential Revision: https://reviews.llvm.org/D81511
LDRD and STRD along with UBFX and SBFX are selected from DAGToDAG
transforms, so do not have tblgen patterns. They don't get marked as
having side effects so cannot be scheduled as efficiently as you would
like.
This specifically marks then as not having side effects.
Differential Revision: https://reviews.llvm.org/D82358
The VLLDM and VLSTM instructions are incompletely specified. They
(potentially) write (or read, respectively) registers Q0-Q7, VPR, and
FPSCR, but the compiler is unaware of it.
In the new test case `cmse-vlldm-no-reorder.ll` case the compiler
missed an anti-dependency and reordered a `VLLDM` ahead of the
instruction, which stashed the return value from the non-secure call,
effectively clobbering said value.
This test case does not fail with upstream LLVM, because of scheduling
differences and I couldn't find a test case for the VLSTM either.
Differential Revision: https://reviews.llvm.org/D81586
Anna Welker