Commit Graph

100 Commits

Author SHA1 Message Date
Simon Pilgrim 48b510c4bc [NFC] Fix compiler warnings due to integer comparison of different signedness
Fix by directly using INT_MAX and INT32_MAX.

Patch by: @nullptr.cpp (Yang Fan)

Differential Revision: https://reviews.llvm.org/D87347
2020-09-11 15:32:03 +01:00
Christopher Tetreault 7ddfd9b3eb [SVE] Bail from VectorUtils heuristics for scalable vectors
Bail from maskIsAllZeroOrUndef and maskIsAllOneOrUndef prior to iterating over the number of
elements for scalable vectors.

Assert that the mask type is not scalable in possiblyDemandedEltsInMask .

Assert that the types are correct in all three functions.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D87424
2020-09-10 12:29:37 -07:00
Craig Topper b16e8687ab [CodeGenPrepare][X86] Teach optimizeGatherScatterInst to turn a splat pointer into GEP with scalar base and 0 index
This helps SelectionDAGBuilder recognize the splat can be used as a uniform base.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D86371
2020-09-02 20:44:12 -07:00
Sanjay Patel 6f3511a01a [ValueTracking] define/use max recursion depth in header
There's a potential motivating case to increase this limit in PR47191:
http://bugs.llvm.org/PR47191

But first we should make it less hacky. The limit in InstCombine is directly tied
to this value because an increase there can cause asserts in the underlying value
tracking calls if not changed together. The usage in VectorUtils is independent,
but the comment suggests that we should use the same value unless there's a known
reason to diverge. There are similar limits in codegen analysis, but I think we
should leave those independent in case we intentionally want the optimization
power/cost to be different there.

Differential Revision: https://reviews.llvm.org/D86113
2020-08-19 16:56:59 -04:00
Craig Topper 3efc978bae [LV] Add abs/smin/smax/umin/umax intrinsics to isTriviallyVectorizable
This patch adds support for vectorizing these intrinsics.

Differential Revision: https://reviews.llvm.org/D84796
2020-07-29 10:23:07 -07:00
Christopher Tetreault 23c5e59d9f [SVE] Remove calls to VectorType::getNumElements from Analysis
Reviewers: efriedma, fpetrogalli, c-rhodes, asbirlea, RKSimon

Reviewed By: RKSimon

Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81504
2020-07-22 15:19:05 -07:00
Serge Pavlov 4d20e31f73 [FPEnv] Intrinsic llvm.roundeven
This intrinsic implements IEEE-754 operation roundToIntegralTiesToEven,
and performs rounding to the nearest integer value, rounding halfway
cases to even. The intrinsic represents the missed case of IEEE-754
rounding operations and now llvm provides full support of the rounding
operations defined by the standard.

Differential Revision: https://reviews.llvm.org/D75670
2020-05-26 19:24:58 +07:00
Sanjay Patel 7eed772a27 [PatternMatch] abbreviate vector inst matchers; NFC
Readability is not reduced with these opcodes/match lines,
so reduce odds of awkward wrapping from 80-col limit.
2020-05-24 09:19:47 -04:00
Nikita Popov 52e98f620c [Alignment] Remove unnecessary getValueOrABITypeAlignment calls (NFC)
Now that load/store alignment is required, we no longer need most
of them. Also switch the getLoadStoreAlignment() helper to return
Align instead of MaybeAlign.
2020-05-17 22:19:15 +02:00
Anna Thomas 7cc3769adb [VectorUtils] Expose vector-function-abi-variant mangling as a utility.
Summary:
This change exposes the vector name mangling with LLVM ISA (used as part
of vector-function-abi-variant) as a utility.
This can then be used by front-ends that add this attribute.
Note that all parameters passed in to the function will be mangled with
the "v" token to identify that they are of of vector type. So, it is the
responsibility of the caller to confirm that all parameters in the
vectorized variant is of vector type.

Added unit test to show vector name mangling.

Reviewed-By: fpetrogalli, simoll

Differential Revision: https://reviews.llvm.org/D79867
2020-05-15 11:42:20 -04:00
Huihui Zhang 1ec0cc0f02 [InstCombine][SVE] Fix visitExtractElementInst for scalable type.
Summary:
This patch fix the following issues with visitExtractElementInst:

      1. Restrict VectorUtils::findScalarElement to fixed-length vector.
         For scalable type, the number of elements in shuffle mask is
         unknown at compile-time.
      2. Fix out-of-range calculation for fixed-length vector.
      3. Skip scalable type when analysis rely on fixed number of elements.
      4. Add unit tests to check functionality of extractelement for scalable type.

Reviewers: sdesmalen, efriedma, spatel, nikic

Reviewed By: efriedma

Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78267
2020-05-07 13:03:52 -07:00
Christopher Tetreault 9174e0229f [SVE] Remove calls to VectorType::isScalable from analysis
Reviewers: efriedma, sdesmalen, chandlerc, sunfish

Reviewed By: efriedma

Subscribers: tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77692
2020-04-23 12:44:22 -07:00
Craig Topper be04aba6fc [CallSite removal][ValueTracking] Use CallBase instead of ImmutableCallSite for getIntrinsicForCallSite. NFC
Differential Revision: https://reviews.llvm.org/D78613
2020-04-22 12:06:58 -07:00
Florian Hahn 2737362e7a [VectorUtils] Use early_inc_range instead of DelSet (NFC).
DelSet was used to avoid invalidating the current iterator while
modifying the map we are iterating over.

By using an early_inc_range, (which increments to iterator 'early',
allowing us to remove the current element), we can get rid of DelSet.

Reviewers: gilr, rengolin, Ayal, hsaito

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D78420
2020-04-20 16:36:26 +01:00
Florian Hahn 4ee45ab60f [LV] Invalidate cost model decisions along with interleave groups.
Cost-modeling decisions are tied to the compute interleave groups
(widening decisions, scalar and uniform values). When invalidating the
interleave groups, those decisions also need to be invalidated.

Otherwise there is a mis-match during VPlan construction.
VPWidenMemoryRecipes created initially are left around w/o converting them
into VPInterleave recipes. Such a conversion indeed should not take place,
and these gather/scatter recipes may in fact be right. The crux is leaving around
obsolete CM_Interleave (and dependent) markings of instructions along with
their costs, instead of recalculating decisions, costs, and recipes.

Alternatively to forcing a complete recompute later on, we could try
to selectively invalidate the decisions connected to the interleave
groups. But we would likely need to run the uniform/scalar value
detection parts again anyways and the extra complexity is probably not
worth it.

Fixes PR45572.

Reviewers: gilr, rengolin, Ayal, hsaito

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D78298
2020-04-18 10:23:49 +01:00
Benjamin Kramer 166467e822 [VectorUtils] Create shufflevector masks as int vectors instead of Constants
No functionality change intended.
2020-04-17 15:28:00 +02:00
Sanjay Patel c23cbefd9d [VectorUtils] add IR-level analysis for widening of shuffle mask
This is similar to the recent move/addition of "scaleShuffleMask" (D76508),
but there are a couple of differences:

1. The existing x86 helper (canWidenShuffleElements) always tries to
   divide-by-2, so it gets called iteratively and wouldn't handle the
   general case of non-pow-2 length.
2. The existing x86 code handles "SM_SentinelZero" - we don't have
   that in IR, but this code should be safe to use with that or other
   special (negative) values.

The motivation is to enable shuffle folds in instcombine/vector-combine
that are similar to D76844 and D76727, but in the reverse-bitcast direction.
Those patterns are visible in the tests for D40633.

Differential Revision: https://reviews.llvm.org/D77881
2020-04-12 10:14:19 -04:00
Sanjay Patel 1318ddbc14 [VectorUtils] rename scaleShuffleMask to narrowShuffleMaskElts; NFC
As proposed in D77881, we'll have the related widening operation,
so this name becomes too vague.

While here, change the function signature to take an 'int' rather
than 'size_t' for the scaling factor, add an assert for overflow of
32-bits, and improve the documentation comments.
2020-04-11 10:05:49 -04:00
Christopher Tetreault b96558f5e5 Clean up usages of asserting vector getters in Type
Summary:
Remove usages of asserting vector getters in Type in preparation for the
VectorType refactor. The existence of these functions complicates the
refactor while adding little value.

Reviewers: sunfish, sdesmalen, efriedma

Reviewed By: efriedma

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77273
2020-04-09 12:41:28 -07:00
Craig Topper f92563f907 [VectorUtils][X86] De-templatize scaleShuffleMask and 2 X86 shuffle mask helpers and move their implementation to cpp files
Summary: These were templated due to SelectionDAG using int masks for shuffles and IR using unsigned masks for shuffles. But now that D72467 has landed we have an int mask version of IRBuilder::CreateShuffleVector. So just use int instead of a template

Reviewers: spatel, efriedma, RKSimon

Reviewed By: efriedma

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D77183
2020-04-01 00:46:48 -07:00
Eli Friedman 1ee6ec2bf3 Remove "mask" operand from shufflevector.
Instead, represent the mask as out-of-line data in the instruction. This
should be more efficient in the places that currently use
getShuffleVector(), and paves the way for further changes to add new
shuffles for scalable vectors.

This doesn't change the syntax in textual IR. And I don't currently plan
to change the bitcode encoding in this patch, although we'll probably
need to do something once we extend shufflevector for scalable types.

I expect that once this is finished, we can then replace the raw "mask"
with something more appropriate for scalable vectors.  Not sure exactly
what this looks like at the moment, but there are a few different ways
we could handle it.  Maybe we could try to describe specific shuffles.
Or maybe we could define it in terms of a function to convert a fixed-length
array into an appropriate scalable vector, using a "step", or something
like that.

Differential Revision: https://reviews.llvm.org/D72467
2020-03-31 13:08:59 -07:00
Huihui Zhang 8f52573962 [InstSimplify][SVE] Fix SimplifyInsert/ExtractElementInst for scalable vector.
Summary:
For scalable vector, index out-of-bound can not be determined at compile-time.
The same apply for VectorUtil findScalarElement().

Add test cases to check the functionality of SimplifyInsert/ExtractElementInst for scalable vector.

Reviewers: sdesmalen, efriedma, spatel, apazos

Reviewed By: efriedma

Subscribers: cameron.mcinally, tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75782
2020-03-11 15:09:56 -07:00
Nikita Popov f37e899fd7 [VectorUtils] Accept IRBuilderBase; NFC 2020-02-18 18:02:04 +01:00
Jim Lin 466f8843f5 [NFC] Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h,td}
2020-02-18 10:49:13 +08:00
Sanjay Patel 686a038ed8 [Analysis] add query to get splat value from array of ints
I was debug stepping through an x86 shuffle lowering and
noticed we were doing an N^2 search for splat index. I
didn't find the equivalent functionality anywhere else in
LLVM, so here's a helper that takes an array of int and
returns a splatted index while ignoring undefs (any
negative value).

This might also be used inside existing
ShuffleVectorInst/ShuffleVectorSDNode functions and/or
help with D72467.

Differential Revision: https://reviews.llvm.org/D74064
2020-02-05 14:55:02 -05:00
Sanjay Patel 9b9e2da07d [Analysis] add optional index parameter to isSplatValue()
We want to allow splat value transforms to improve PR44588 and related bugs:
https://bugs.llvm.org/show_bug.cgi?id=44588
...but to do that, we need to know if values are splatted from the same,
specific index (lane) rather than splatted from an arbitrary index.

We can improve the undef handling with 1-liner follow-ups because the
Constant API optionally allow undefs now.

Differential Revision: https://reviews.llvm.org/D73549
2020-02-02 10:52:00 -05:00
Francesco Petrogalli 623cff81fe [llvm][VectorUtils] Tweak VFShape for scalable vector functions.
Summary:
This patch makes sure that the field VFShape.VF is greater than zero
when demangling the vector function name of scalable vector functions
encoded in the "vector-function-abi-variant" attribute.

This change is required to be able to provide instances of VFShape
that can be used to query the VFDatabase for the vectorization passes,
as such passes always require a positive value for the Vectorization Factor (VF)
needed by the vectorization process.

It is not possible to extract the value of VFShape.VF from the mangled
name of scalable vector functions, because it is encoded as
`x`. Therefore, the VFABI demangling function has been modified to
extract such information from the IR declaration of the vector
function, under the assumption that _all_ vectors in the signature of
the vector function have the same number of lanes. Such assumption is
valid because it is also assumed by the Vector Function ABI
specifications supported by the demangling function (x86, AArch64, and
LLVM internal one).

The unit tests that demangle scalable names have been modified by
adding the IR module that carries the declaration of the vector
function name being demangled.

In particular, the demangling function fails in the following cases:

1. When the declaration of the scalable vector function is not
    present in the module.

2. When the value of VFSHape.VF is not greater than 0.

Reviewers: jdoerfert, sdesmalen, andwar

Reviewed By: jdoerfert

Subscribers: mgorny, kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73286
2020-01-30 05:53:56 +00:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Francesco Petrogalli 66c120f025 [VectorUtils] Rework the Vector Function Database (VFDatabase).
Summary:
This commits is a rework of the patch in
https://reviews.llvm.org/D67572.

The rework was requested to prevent out-of-tree performance regression
when vectorizing out-of-tree IR intrinsics. The vectorization of such
intrinsics is enquired via the static function `isTLIScalarize`. For
detail see the discussion in https://reviews.llvm.org/D67572.

Reviewers: uabelho, fhahn, sdesmalen

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72734
2020-01-16 15:08:26 +00:00
Francesco Petrogalli 19f73f0d1b Revert "[VectorUtils] Introduce the Vector Function Database (VFDatabase)."
This reverts commit 0be81968a2.

The VFDatabase needs some rework to be able to handle vectorization
and subsequent scalarization of intrinsics in out-of-tree versions of
the compiler. For more details, see the discussion in
https://reviews.llvm.org/D67572.
2019-12-13 19:42:04 +00:00
Francesco Petrogalli 0be81968a2 [VectorUtils] Introduce the Vector Function Database (VFDatabase).
This patch introduced the VFDatabase, the framework proposed in
http://lists.llvm.org/pipermail/llvm-dev/2019-June/133484.html. [*]

In this patch the VFDatabase is used to bridge the TargetLibraryInfo
(TLI) calls that were previously used to query for the availability of
vector counterparts of scalar functions.

The VFISAKind field `ISA` of VFShape have been moved into into VFInfo,
under the assumption that different vector ISAs may provide the same
vector signature. At the moment, the vectorizer accepts any of the
available ISAs as long as the signature provided by the VFDatabase
matches the one expected in the vectorization process. For example,
when targeting AVX or AVX2, which both have 256-bit registers, the IR
signature of the two vector functions associated to the two ISAs is
the same. The `getVectorizedFunction` method at the moment returns the
first available match. We will need to add more heuristics to the
search system to decide which of the available version (TLI, AVX,
AVX2, ...)  the system should prefer, when multiple versions with the
same VFShape are present.

Some of the code in this patch is based on the work done by Sumedh
Arani in https://reviews.llvm.org/D66025.

[*] Notice that in the proposal the VFDatabase was called SVFS. The
name VFDatabase is more in line with LLVM recommendations for
naming classes and variables.

Differential Revision: https://reviews.llvm.org/D67572
2019-12-10 16:36:44 +00:00
Francesco Petrogalli eac93757c3 [VectorUtils] API for VFShape, update VFInfo.
Summary:
This patch introduces an API to build and modify vector shapes.

The validity of a VFShape can be checked with the
`hasValidParameterList` method, which is also run in an assertion each
time a VFShape is modified.

The field VFISAKind has been moved to VFInfo under the assumption that
different ISAs can map to the same VFShape (as it can be in the case
of vector extensions with the same registers size, for example AVX and
AVX2).

Reviewers: sdesmalen, jdoerfert, simoll, hsaito

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70513
2019-12-04 20:40:05 +00:00
Francesco Petrogalli d6de5f12d4 [SVFS] Inject TLI Mappings in VFABI attribute.
This patch introduces a function pass to inject the scalar-to-vector
mappings stored in the TargetLIbraryInfo (TLI) into the Vector
Function ABI (VFABI) variants attribute.

The test is testing the injection for three vector libraries supported
by the TLI (Accelerate, SVML, MASSV).

The pass does not change any of the analysis associated to the
function.

Differential Revision: https://reviews.llvm.org/D70107
2019-11-15 18:42:56 +00:00
Reid Kleckner 4c1a1d3cf9 Add missing includes needed to prune LLVMContext.h include, NFC
These are a pre-requisite to removing #include "llvm/Support/Options.h"
from LLVMContext.h: https://reviews.llvm.org/D70280
2019-11-14 15:23:15 -08:00
Francesco Petrogalli e9a06e0606 [VFABI] Read/Write functions for the VFABI attribute.
The attribute is stored at the `FunctionIndex` attribute set, with the
name "vector-function-abi-variant".

The get/set methods of the attribute have assertion to verify that:

1. Each name in the attribute is a valid VFABI mangled name.

2. Each name in the attribute correspond to a function declared in the
   module.

Differential Revision: https://reviews.llvm.org/D69976
2019-11-12 03:40:42 +00:00
Guillaume Chatelet 837a1b84ce [Alignment][NFC] Make VectorUtils uas llvm::Align
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: hiraditya, rogfer01, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68784

llvm-svn: 374330
2019-10-10 12:35:04 +00:00
Simon Pilgrim c52a7093df InterleavedAccessInfo - Don't dereference a dyn_cast result. NFCI.
llvm-svn: 372117
2019-09-17 13:25:56 +00:00
Bjorn Pettersson 5e331e4ce8 [Intrinsic] Add the llvm.umul.fix.sat intrinsic
Summary:
Add an intrinsic that takes 2 unsigned integers with
the scale of them provided as the third argument and
performs fixed point multiplication on them. The
result is saturated and clamped between the largest and
smallest representable values of the first 2 operands.

This is a part of implementing fixed point arithmetic
in clang where some of the more complex operations
will be implemented as intrinsics.

Patch by: leonardchan, bjope

Reviewers: RKSimon, craig.topper, bevinh, leonardchan, lebedev.ri, spatel

Reviewed By: leonardchan

Subscribers: ychen, wuzish, nemanjai, MaskRay, jsji, jdoerfert, Ka-Ka, hiraditya, rjmccall, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57836

llvm-svn: 371308
2019-09-07 12:16:14 +00:00
Hideki Saito 09fac2450b [LV] Avoid building interleaved group in presence of WAW dependency
Reviewers: hsaito, Ayal, fhahn, anna, mkazantsev

Reviewed By: hsaito

Patch by evrevnov, thanks!

Differential Revision: https://reviews.llvm.org/D63981

llvm-svn: 367654
2019-08-02 06:31:50 +00:00
Bjorn Pettersson 512b118779 [Scalarizer] Add scalarizer support for smul.fix.sat
Summary:
Handle smul.fix.sat in the scalarizer. This is done by
adding smul.fix.sat to the set of "isTriviallyVectorizable"
intrinsics.

The addition of smul.fix.sat in isTriviallyVectorizable and
hasVectorInstrinsicScalarOpd can also be seen as a preparation
to be able to use hasVectorInstrinsicScalarOpd in ConstantFolding.

Reviewers: rengolin, RKSimon, dblaikie

Reviewed By: rengolin

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63704

llvm-svn: 364177
2019-06-24 12:07:11 +00:00
Sanjay Patel 40e3bdf876 [Analysis] add isSplatValue() for vectors in IR
We have the related getSplatValue() already in IR (see code just above the proposed addition).
But sometimes we only need to know that the value is a splat rather than capture the splatted
scalar value. Also, we have an isSplatValue() function already in SDAG.

Motivation - recent bugs that would potentially benefit from improved splat analysis in IR:
https://bugs.llvm.org/show_bug.cgi?id=37428
https://bugs.llvm.org/show_bug.cgi?id=42174

Differential Revision: https://reviews.llvm.org/D63138

llvm-svn: 363106
2019-06-11 22:25:18 +00:00
Sanjay Patel e490e4a0e7 [Analysis] simplify code for getSplatValue(); NFC
AFAIK, this is only currently called by TTI, but it could be
used from instcombine or CGP to help solve problems like:
https://bugs.llvm.org/show_bug.cgi?id=37428
https://bugs.llvm.org/show_bug.cgi?id=42174

llvm-svn: 362810
2019-06-07 16:09:54 +00:00
Philip Reames 88cd69b56f Consolidate existing utilities for interpreting vector predicate maskes [NFC]
llvm-svn: 359163
2019-04-25 02:30:17 +00:00
Simon Pilgrim a066f1f9e6 [Vectorizer] Add vectorization support for fixed smul/umul intrinsics
This requires a couple of tweaks to existing vectorization functions as they were assuming that only the second call argument (ctlz/cttz/powi) could ever be the 'always scalar' argument, but for smul.fix + umul.fix its the third argument.

Differential Revision: https://reviews.llvm.org/D58616

llvm-svn: 354790
2019-02-25 15:42:02 +00:00
Hiroshi Inoue 02a2bb2f54 [NFC] fix trivial typos in comments
llvm-svn: 353147
2019-02-05 08:30:48 +00:00
Simon Pilgrim 0e08b6f017 Move saturated arithmetic intrinsics to other integer intrinsics. NFCI.
They were in the floating point group.

llvm-svn: 351953
2019-01-23 13:49:10 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Simon Pilgrim c2aadfaaad [SLPVectorizer] Flag ADD/SUB SSAT/USAT intrinsics trivially vectorizable (PR40123)
Enables SLP vectorization for the SSE2 PADDS/PADDUS/PSUBS/PSUBUS style intrinsics

llvm-svn: 350300
2019-01-03 12:18:23 +00:00
Clement Courbet d4bd3eb85d [NFC] Fix trailing comma after function.
lib/Analysis/VectorUtils.cpp:482:2: warning: extra ‘;’ [-Wpedantic]

llvm-svn: 349732
2018-12-20 09:20:07 +00:00
Michael Kruse 978ba61536 Introduce llvm.loop.parallel_accesses and llvm.access.group metadata.
The current llvm.mem.parallel_loop_access metadata has a problem in that
it uses LoopIDs. LoopID unfortunately is not loop identifier. It is
neither unique (there's even a regression test assigning the some LoopID
to multiple loops; can otherwise happen if passes such as LoopVersioning
make copies of entire loops) nor persistent (every time a property is
removed/added from a LoopID's MDNode, it will also receive a new LoopID;
this happens e.g. when calling Loop::setLoopAlreadyUnrolled()).
Since most loop transformation passes change the loop attributes (even
if it just to mark that a loop should not be processed again as
llvm.loop.isvectorized does, for the versioned and unversioned loop),
the parallel access information is lost for any subsequent pass.

This patch unlinks LoopIDs and parallel accesses.
llvm.mem.parallel_loop_access metadata on instruction is replaced by
llvm.access.group metadata. llvm.access.group points to a distinct
MDNode with no operands (avoiding the problem to ever need to add/remove
operands), called "access group". Alternatively, it can point to a list
of access groups. The LoopID then has an attribute
llvm.loop.parallel_accesses with all the access groups that are parallel
(no dependencies carries by this loop).

This intentionally avoid any kind of "ID". Loops that are clones/have
their attributes modifies retain the llvm.loop.parallel_accesses
attribute. Access instructions that a cloned point to the same access
group. It is not necessary for each access to have it's own "ID" MDNode,
but those memory access instructions with the same behavior can be
grouped together.

The behavior of llvm.mem.parallel_loop_access is not changed by this
patch, but should be considered deprecated.

Differential Revision: https://reviews.llvm.org/D52116

llvm-svn: 349725
2018-12-20 04:58:07 +00:00