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Commit Graph

416 Commits

Author SHA1 Message Date
Mircea Trofin
5f8ff6c8ac [llvm] Moved InlineSizeEstimatorAnalysis test to .ll
Summary:
Following guidance in
https://llvm.org/docs/TestingGuide.html#testing-analysis

Reviewers: mehdi_amini

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83918
2020-07-16 12:25:16 -07:00
Eric Christopher
3a125536d7 Temporarily Revert "[AssumeBundles] Use operand bundles to encode alignment assumptions"
due to the performance bugs filed in https://bugs.llvm.org/show_bug.cgi?id=46753.

An SROA change soon may obviate some of these problems.

This reverts commit 8d09f20798ac180b1749276bff364682ce0196ab.
2020-07-16 11:54:04 -07:00
Mircea Trofin
b01ead51c6 [llvm][NFC] Hide the tensorflow dependency from headers.
Summary:
This change avoids exposing tensorflow types when including TFUtils.h.
They are just an implementation detail, and don't need to be used
directly when implementing an analysis requiring ML model evaluation.

The TFUtils APIs, while generically typed, are still not exposed unless
the tensorflow C library is present, as they currently have no use
otherwise.

Reviewers: mehdi_amini, davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83843
2020-07-14 21:14:11 -07:00
Mircea Trofin
788f9832ab [llvm][NFC] expose LLVM_HAVE_TF_API through llvm-config.h
Summary:
This allows users of the llvm library discover whether llvm was built
with the tensorflow c API dependency, which helps if using the TFUtils
wrapper, for example.

We don't do the same for the LLVM_HAVE_TF_AOT flag, because that does
not expose any API.

Reviewers: mehdi_amini, davidxl

Subscribers: mgorny, aaron.ballman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83746
2020-07-14 14:09:35 -07:00
Mircea Trofin
d4fa8385c7 Reapply "[llvm] Native size estimator for training -Oz inliner"
This reverts commit 9908a3b9f521c954cbf6adcec35b14b2f6c8da49.

The fix was to exclude the content of TFUtils.h (automatically
included in the LLVM_Analysis module, when LLVM_ENABLE_MODULES is enabled).

Differential Revision: https://reviews.llvm.org/D82817
2020-07-13 16:26:26 -07:00
Tyker
174a27b790 [AssumeBundles] Use operand bundles to encode alignment assumptions
Summary:
NOTE: There is a mailing list discussion on this: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137632.html

Complemantary to the assumption outliner prototype in D71692, this patch
shows how we could simplify the code emitted for an alignemnt
assumption. The generated code is smaller, less fragile, and it makes it
easier to recognize the additional use as a "assumption use".

As mentioned in D71692 and on the mailing list, we could adopt this
scheme, and similar schemes for other patterns, without adopting the
assumption outlining.

Reviewers: hfinkel, xbolva00, lebedev.ri, nikic, rjmccall, spatel, jdoerfert, sstefan1

Reviewed By: jdoerfert

Subscribers: thopre, yamauchi, kuter, fhahn, merge_guards_bot, hiraditya, bollu, rkruppe, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71739
2020-07-14 01:05:58 +02:00
Davide Italiano
5e0e121c8b Revert "[llvm] Native size estimator for training -Oz inliner"
This reverts commit 83080a294ad7d145d758821bcf4354ad0cb7d299 as
it breaks the macOS modules build.
2020-07-13 13:13:36 -07:00
Mircea Trofin
f77d61cf7b [llvm] Native size estimator for training -Oz inliner
Summary:
This is an experimental ML-based native size estimator, necessary for
computing partial rewards during -Oz inliner policy training. Data
extraction for model training will be provided in a separate patch.

RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-April/140763.html

Reviewers: davidxl, jdoerfert

Subscribers: mgorny, hiraditya, mgrang, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D82817
2020-07-13 10:13:56 -07:00
Sanne Wouda
7ed97c8065 Fix crash when getVFABIMappings is called with an indirect call instruction
Differential Revision: https://reviews.llvm.org/D83122
2020-07-13 15:28:46 +01:00
SharmaRithik
dfc5577648 [CodeMoverUtils] Move OrderedInstructions to CodeMoverUtils
Summary: This patch moves OrderedInstructions to CodeMoverUtils as It was
the only place where OrderedInstructions is required.
Authored By: RithikSharma
Reviewer: Whitney, bmahjour, etiotto, fhahn, nikic
Reviewed By: Whitney, nikic
Subscribers: mgorny, hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D80643
2020-07-10 11:22:43 +05:30
Guillaume Chatelet
966a5c445d [NFC] Adding the align attribute on Atomic{CmpXchg|RMW}Inst
This is the first step to add support for the align attribute to AtomicRMWInst and AtomicCmpXchgInst.
Next step is to add support in IRBuilder and BitcodeReader.
Bug: https://bugs.llvm.org/show_bug.cgi?id=27168

Differential Revision: https://reviews.llvm.org/D83136
2020-07-07 09:54:13 +00:00
Roman Lebedev
cb062e6baf Revert "[AssumeBundles] Use operand bundles to encode alignment assumptions"
Assume bundle can have more than one entry with the same name,
but at least AlignmentFromAssumptionsPass::extractAlignmentInfo() uses
getOperandBundle("align"), which internally assumes that it isn't the
case, and happily crashes otherwise.

Minimal reduced reproducer: run `opt -alignment-from-assumptions` on

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

%0 = type { i64, %1*, i8*, i64, %2, i32, %3*, i8* }
%1 = type opaque
%2 = type { i8, i8, i16 }
%3 = type { i32, i32, i32, i32 }

; Function Attrs: nounwind
define i32 @f(%0* noalias nocapture readonly %arg, %0* noalias %arg1) local_unnamed_addr #0 {
bb:
  call void @llvm.assume(i1 true) [ "align"(%0* %arg, i64 8), "align"(%0* %arg1, i64 8) ]
  ret i32 0
}

; Function Attrs: nounwind willreturn
declare void @llvm.assume(i1) #1

attributes #0 = { nounwind "reciprocal-estimates"="none" }
attributes #1 = { nounwind willreturn }


This is what we'd have with -mllvm -enable-knowledge-retention

This reverts commit c95ffadb2474a4d8c4f598d94d35a9f31d9606cb.
2020-07-04 23:49:23 +03:00
Simon Pilgrim
332483b894 GlobalsModRef.h - reduce CallGraph.h include to forward declarations. NFC.
Fix implicit include dependencies in source files.
2020-06-25 16:00:43 +01:00
Tyker
e767fc4f7e [AssumeBundles] Use operand bundles to encode alignment assumptions
Summary:
NOTE: There is a mailing list discussion on this: http://lists.llvm.org/pipermail/llvm-dev/2019-December/137632.html

Complemantary to the assumption outliner prototype in D71692, this patch
shows how we could simplify the code emitted for an alignemnt
assumption. The generated code is smaller, less fragile, and it makes it
easier to recognize the additional use as a "assumption use".

As mentioned in D71692 and on the mailing list, we could adopt this
scheme, and similar schemes for other patterns, without adopting the
assumption outlining.

Reviewers: hfinkel, xbolva00, lebedev.ri, nikic, rjmccall, spatel, jdoerfert, sstefan1

Reviewed By: jdoerfert

Subscribers: yamauchi, kuter, fhahn, merge_guards_bot, hiraditya, bollu, rkruppe, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71739
2020-06-25 12:59:44 +02:00
Simon Pilgrim
dcda485b5b ProfileSummaryInfoTest.cpp - fix implicit CommandLine.h dependency. NFC.
ProfileSummaryInfoTest references cl::opt but don't include CommandLine.h.
2020-06-23 13:07:18 +01:00
Simon Pilgrim
30d12a5b04 ScalarEvolution.h - reduce LoopInfo.h include to forward declarations. NFC.
Move ScalarEvolution::forgetLoopDispositions implementation to ScalarEvolution.cpp to remove the dependency.

Add implicit header dependency to source files where necessary.
2020-06-17 15:48:23 +01:00
Christopher Tetreault
61e16ba8f2 [SVE] Deprecate default false variant of VectorType::get
Reviewers: efriedma, fpetrogalli, kmclaughlin, huntergr

Reviewed By: fpetrogalli

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

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D80342
2020-06-16 15:16:11 -07:00
Hiroshi Yamauchi
b2733d94ae [TLI] Add four C++17 delete variants.
Summary:
delete(void*, unsigned int, align_val_t)
delete(void*, unsigned long, align_val_t)
delete[](void*, unsigned int, align_val_t)
delete[](void*, unsigned long, align_val_t)

Differential Revision: https://reviews.llvm.org/D81853
2020-06-16 11:12:02 -07:00
Mircea Trofin
534cba2336 [llvm][NFC] Move content of ML subdirectory into Analysis
The initial intent was to organize ML stuff in its own directory, but
it turns out that conflicts with llvm component layering policies: it
is not a component, because subsequent changes want to rely on other
analyses, which would create a cycle; and we don't have a reliable,
cross-platform mechanism to compile files in a subdirectory, and fit in
the existing LLVM build structure.

This change moves the files into Analysis, and subsequent changes will
leverage conditional compilation for those that have optional
dependencies.
2020-06-15 14:35:33 -07:00
Mircea Trofin
982fab44f8 Revert "[llvm] Added support for stand-alone cmake object libraries."
This reverts commit 695c7d6313d74dc02222f6497d4c4985d67f433f.

Breaks windows (e.g.
http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/16497)

Likely to cause problems with XCode.
2020-06-15 12:15:39 -07:00
Mircea Trofin
a46434135a [llvm] Added support for stand-alone cmake object libraries.
Summary:
Currently, add_llvm_library would create an OBJECT library alongside
of a STATIC / SHARED library, but losing the link interface (its
elements would become dependencies instead). To support scenarios
where linking an object library also brings in its usage
requirements, this patch adds support for 'stand-alone' OBJECT
libraries - i.e. without an accompanying SHARED/STATIC library, and
maintaining the link interface defined by the user.

The support is via a new option, OBJECT_ONLY, to avoid breaking changes
- since just specifying "OBJECT" would currently imply also STATIC or
SHARED, depending on BUILD_SHARED_LIBS.

This is useful for cases where, for example, we want to build a part
of a component separately. Using a STATIC target would incur the risk
that symbols not referenced in the consumer would be dropped (which may
be undesirable).

The current application is the ML part of Analysis. It should be part
of the Analysis component, so it may reference other analyses; and (in
upcoming changes) it has dependencies on optional libraries.

Reviewers: karies, davidxl

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81447
2020-06-15 12:01:43 -07:00
Wenlei He
f6c8ca4756 [NewPM] Avoid redundant CGSCC run for updated SCC
Summary:
When an SCC got split due to inlining, we have two mechanisms for reprocessing the updated SCC, first is UR.UpdatedC
that repeatedly rerun the new, current SCC; second is a worklist for all newly split SCCs. We can avoid rerun of
the same SCC when the SCC is set to be processed by both mechanisms *back to back*. In pathological cases, such redundant
rerun could cause exponential size growth due to inlining along cycles, even when there's no SCC mutation and hence
convergence is not a problem.

Note that it's ok to have SCC updated and rerun immediately, and also in the work list if we have actually moved an SCC
to be topologically "below" the current one due to merging. In that case, we will need to revisit the current SCC after
those moved SCCs. For that reason, the redundant avoidance here only targets back to back rerun of the same SCC - the
case described by the now removed FIXME comment.

Reviewers: chandlerc, wmi

Subscribers: llvm-commits, hoy

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80589
2020-06-14 19:54:52 -07:00
Simon Pilgrim
4dedca4724 LoopAnalysisManager.h - reduce includes to forward declarations. NFC.
Move implicit include dependencies down to header/source files.
2020-06-06 14:06:46 +01:00
Simon Pilgrim
4f8fb4d4d7 TargetLibraryInfo.h - reduce Triple.h include to forward declaration. NFC.
Move implicit include dependencies down to source files.
2020-06-05 14:35:30 +01:00
Hiroshi Yamauchi
c65f25e192 [PGO] Improve the working set size heuristics under the partial sample PGO.
Summary:
The working set size heuristics (ProfileSummaryInfo::hasHugeWorkingSetSize)
under the partial sample PGO may not be accurate because the profile is partial
and the number of hot profile counters in the ProfileSummary may not reflect the
actual working set size of the program being compiled.

To improve this, the (approximated) ratio of the the number of profile counters
of the program being compiled to the number of profile counters in the partial
sample profile is computed (which is called the partial profile ratio) and the
working set size of the profile is scaled by this ratio to reflect the working
set size of the program being compiled and used for the working set size
heuristics.

The partial profile ratio is approximated based on the number of the basic
blocks in the program and the NumCounts field in the ProfileSummary and computed
through the thin LTO indexing. This means that there is the limitation that the
scaled working set size is available to the thin LTO post link passes only.

Reviewers: davidxl

Subscribers: mgorny, eraman, hiraditya, steven_wu, dexonsmith, arphaman, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79831
2020-06-01 10:29:23 -07:00
Mircea Trofin
bd7106c9d8 [llvm] Add function feature extraction analysis
Summary:
This patch introduces an analysis pass to extract function features,
which will be needed by the ML InlineAdvisor.

RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-April/140763.html

Reviewers: davidxl, dblaikie, jdoerfert

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80579
2020-05-27 13:38:50 -07:00
Bardia Mahjour
5d0bb232c2 [DDG] Data Dependence Graph - Add query function for memory dependencies between two nodes
Summary:
When working with the DDG it's useful to be able to query details of the
memory dependencies between two nodes connected by a memory edge. The DDG
does not hold a copy of the dependencies, but it contains a reference to a
DependenceInfo object through which dependence information can be queried.
This patch adds a query function to the DDG to obtain all the Dependence
objects that exist between instructions of two nodes.

Authored By: bmahjour

Reviewers: Meinersbur, Whitney, etiotto

Reviewed By: Whitney

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80529
2020-05-27 12:40:14 -04:00
Paul Walker
c2c5d749a2 [VFABI] Fix parsing of uniform parameters that shouldn't expect step or positional data.
Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80575
2020-05-27 16:07:45 +00:00
Serge Pavlov
e9538ca02f [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
Florian Hahn
dbd4f386aa [ValueTracking] Use assumptions in computeConstantRange.
This patch updates computeConstantRange to optionally take an assumption
cache as argument and use the available assumptions to limit the range
of the result.

Currently this is limited to assumptions that are comparisons.

Reviewers: reames, nikic, spatel, jdoerfert, lebedev.ri

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D76193
2020-05-23 20:07:52 +01:00
Florian Hahn
69f89dfbd9 [SCEV] Move ScalarEvolutionExpander.cpp to Transforms/Utils (NFC).
SCEVExpander modifies the underlying function so it is more suitable in
Transforms/Utils, rather than Analysis. This allows using other
transform utils in SCEVExpander.

This patch was originally committed as b8a3c34eee06, but broke the
modules build, as LoopAccessAnalysis was using the Expander.

The code-gen part of LAA was moved to lib/Transforms recently, so this
patch can be landed again.

Reviewers: sanjoy.google, efriedma, reames

Reviewed By: sanjoy.google

Differential Revision: https://reviews.llvm.org/D71537
2020-05-20 10:53:40 +01:00
Nikita Popov
14ba2f0ba5 [ValueTracking] Fix computeKnownBits() with bitwidth-changing ptrtoint
computeKnownBitsFromAssume() currently asserts if m_V matches a
ptrtoint that changes the bitwidth. Because InstCombine
canonicalizes ptrtoint instructions to use explicit zext/trunc,
we never ran into the issue in practice. I'm adding unit tests,
as I don't know if this can be triggered via IR anywhere.

Fix this by calling anyextOrTrunc(BitWidth) on the computed
KnownBits. Note that we are going from the KnownBits of the
ptrtoint result to the KnownBits of the ptrtoint operand,
so we need to truncate if the ptrtoint zexted and anyext if
the ptrtoint truncated.

Differential Revision: https://reviews.llvm.org/D79234
2020-05-16 14:17:11 +02:00
Anna Thomas
8194578ca4 [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
Alina Sbirlea
c25b0c2bff [NewPassManager] Add assertions when getting statefull cached analysis.
Summary:
Analyses that are statefull should not be retrieved through a proxy from
an outer IR unit, as these analyses are only invalidated at the end of
the inner IR unit manager.
This patch disallows getting the outer manager and provides an API to
get a cached analysis through the proxy. If the analysis is not
stateless, the call to getCachedResult will assert.

Reviewers: chandlerc

Subscribers: mehdi_amini, eraman, hiraditya, zzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D72893
2020-05-13 12:38:38 -07:00
Juneyoung Lee
d6be273bbc [ValueTracking] Let propagatesPoison support binops/unaryops/cast/etc.
Summary:
This patch makes propagatesPoison be more accurate by returning true on
more bin ops/unary ops/casts/etc.

The changed test in ScalarEvolution/nsw.ll was introduced by
a19edc4d15 .
IIUC, the goal of the tests is to show that iv.inc's SCEV expression still has
no-overflow flags even if the loop isn't in the wanted form.
It becomes more accurate with this patch, so think this is okay.

Reviewers: spatel, lebedev.ri, jdoerfert, reames, nikic, sanjoy

Reviewed By: spatel, nikic

Subscribers: regehr, nlopes, efriedma, fhahn, javed.absar, llvm-commits, hiraditya

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78615
2020-05-13 02:51:42 +09:00
Nikita Popov
0eae65a653 [ValueTracking] Convert test to unit test (NFC)
Test this directly, rather than going through InstSimplify.
2020-05-03 12:23:57 +02:00
Anh Tuyen Tran
3734d8462b [VFDatabase] Scalar functions are vector functions with VF =1
Summary:
Return scalar function when VF==1. The new trivial mapping scalar --> scalar when VF==1 to prevent false positive for "isVectorizable" query.

Author: masoud.ataei (Masoud Ataei)

Reviewers: Whitney (Whitney Tsang), fhahn (Florian Hahn), pjeeva01 (Jeeva P.), fpetrogalli (Francesco Petrogalli), rengolin (Renato Golin)

Reviewed By: fpetrogalli (Francesco Petrogalli)

Subscribers: hiraditya (Aditya Kumar), llvm-commits, LLVM

Tag: LLVM

Differential Revision: https://reviews.llvm.org/D78054
2020-04-29 17:20:37 +00:00
Tyker
8a1b84f3ac [AssumeBundles] Refactor asssume builder
Summary:
refactor assume bulider for the next patch.
the assume builder now generate only one assume per attribute kind and per value they are on. to do this it takes the highest. this is desirable because currently, for all attributes the higest value is the most valuable.

Reviewers: jdoerfert

Reviewed By: jdoerfert

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78013
2020-04-25 13:43:52 +02:00
Craig Topper
16d452e561 [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
Craig Topper
bb554c7b77 [CallSite removal] Remove unneeded includes of CallSite.h. NFC 2020-04-22 00:07:13 -07:00
Craig Topper
c168418ffb [CallSite removal][Analysis] Use CallBase instead of CallSite in SparsePropagation unit test. NFC 2020-04-19 22:39:24 -07:00
Mircea Trofin
6e2b52a866 [llvm][NFC] Dereferencing before cast-ing in ProfileSummaryInfoTest
Incorporated feedback from https://reviews.llvm.org/D78414
2020-04-18 17:47:37 -07:00
Mircea Trofin
0ca1b1c956 [llvm][NFC][CallSite] Remove CallSite from ProfileSummary
Summary: Depends on D78395.

Reviewers: craig.topper, dblaikie, wmi, davidxl

Subscribers: eraman, hiraditya, haicheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78414
2020-04-18 12:03:14 -07:00
Craig Topper
3454be975b [CallSite removal][TargetLibraryInfo] Replace ImmutableCallSite with CallBase in one of the getLibFunc signatures. NFC
Differential Revision: https://reviews.llvm.org/D78083
2020-04-15 22:43:41 -07:00
Juneyoung Lee
64eac7a6cd [ValueTracking] Implement canCreatePoison
Summary:
This PR adds `canCreatePoison(Instruction *I)` which returns true if `I` can generate poison from non-poison
operands.

Reviewers: spatel, nikic, lebedev.ri

Reviewed By: spatel

Subscribers: hiraditya, llvm-commits, regehr, nlopes

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77890
2020-04-15 05:58:06 +09:00
Aaron Puchert
ac540cb0fe [ValueLattice] Remove unused DataLayout parameter of mergeIn, NFC
Reviewed By: fhahn, echristo

Differential Revision: https://reviews.llvm.org/D78061
2020-04-14 13:32:53 +02:00
Tyker
b6c8c60f14 [AssumeBundles] adapt Assumption cache to assume bundles
Summary: change assumption cache to store an assume along with an index to the operand bundle containing the knowledge.

Reviewers: jdoerfert, hfinkel

Reviewed By: jdoerfert

Subscribers: hiraditya, mgrang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77402
2020-04-13 12:04:51 +02:00
Sanjay Patel
91701e7d4b [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
8105dac4cc [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
Johannes Doerfert
2941d88d79 [CallGraphUpdater] Remove dead constants before replacing a function
Dead constants might be left when a function is replaced, we can
gracefully handle this case and avoid complexity for the users who would
see an assertion otherwise.
2020-04-08 22:52:46 -05:00