950 Commits

Author SHA1 Message Date
Sjoerd Meijer
72855fc09a [LV] Scalar Epilogue Lowering. NFC.
This refactors boolean 'OptForSize' that was passed around in a lot of places.
It controlled folding of the tail loop, the scalar epilogue, into the main loop
but code-size reasons may not be the only reason to do this. Thus, this is a
first step to generalise the concept of tail-loop folding, and hence OptForSize
has been renamed and is using an enum ScalarEpilogueStatus that holds the
status how the epilogue should be lowered.

This will be followed up by D65197, that picks up the predicate loop hint and
performs the tail-loop folding.

Differential Revision: https://reviews.llvm.org/D64916

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366993 91177308-0d34-0410-b5e6-96231b3b80d8
2019-07-25 08:06:02 +00:00
Florian Hahn
bbc7752ec4 [LoopVectorize] Pass unfiltered list of arguments to getIntrinsicInstCost.
We do not compute the scalarization overhead in getVectorIntrinsicCost
and TTI::getIntrinsicInstrCost requires the full arguments list.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366049 91177308-0d34-0410-b5e6-96231b3b80d8
2019-07-15 08:48:47 +00:00
Florian Hahn
3748d783e0 [LV] Exclude loop-invariant inputs from scalar cost computation.
Loop invariant operands do not need to be scalarized, as we are using
the values outside the loop. We should ignore them when computing the
scalarization overhead.

Fixes PR41294

Reviewers: hsaito, rengolin, dcaballe, Ayal

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D59995

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366030 91177308-0d34-0410-b5e6-96231b3b80d8
2019-07-14 20:12:36 +00:00
Orlando Cazalet-Hyams
b1ba8a93bc [DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion
Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

llvm-svn: 363046

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363786 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-19 10:50:47 +00:00
Warren Ristow
31868b92df [LV] Suppress vectorization in some nontemporal cases
When considering a loop containing nontemporal stores or loads for
vectorization, suppress the vectorization if the corresponding
vectorized store or load with the aligment of the original scaler
memory op is not supported with the nontemporal hint on the target.

This adds two new functions:
  bool isLegalNTStore(Type *DataType, unsigned Alignment) const;
  bool isLegalNTLoad(Type *DataType, unsigned Alignment) const;

to TTI, leaving the target independent default implementation as
returning true, but with overriding implementations for X86 that
check the legality based on available Subtarget features.

This fixes https://llvm.org/PR40759

Differential Revision: https://reviews.llvm.org/D61764


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363581 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-17 17:20:08 +00:00
Whitney Tsang
bdd7b78551 PHINode: introduce setIncomingValueForBlock() function, and use it.
Summary:
There is PHINode::getBasicBlockIndex() and PHINode::setIncomingValue()
but no function to replace incoming value for a specified BasicBlock*
predecessor.
Clearly, there are a lot of places that could use that functionality.

Reviewer: craig.topper, lebedev.ri, Meinersbur, kbarton, fhahn
Reviewed By: Meinersbur, fhahn
Subscribers: fhahn, hiraditya, zzheng, jsji, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D63338

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363566 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-17 14:38:56 +00:00
Bjorn Pettersson
784000b4c2 [LV] Deny irregular types in interleavedAccessCanBeWidened
Summary:
Avoid that loop vectorizer creates loads/stores of vectors
with "irregular" types when interleaving. An example of
an irregular type is x86_fp80 that is 80 bits, but that
may have an allocation size that is 96 bits. So an array
of x86_fp80 is not bitcast compatible with a vector
of the same type.

Not sure if interleavedAccessCanBeWidened is the best
place for this check, but it solves the problem seen
in the added test case. And it is the same kind of check
that already exists in memoryInstructionCanBeWidened.

Reviewers: fhahn, Ayal, craig.topper

Reviewed By: fhahn

Subscribers: hiraditya, rkruppe, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63386

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363547 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-17 12:02:24 +00:00
Orlando Cazalet-Hyams
f36c1c031e Revert "[DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion"
This reverts commit 1a0f7a2077b70c9864faa476e15b048686cf1ca7.
See phabricator thread for D60831.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363132 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-12 08:34:51 +00:00
Orlando Cazalet-Hyams
6c60c71a4e [DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion
Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

I have set up a separate review D61933 for a fix which is required for this patch.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel, jmorse

Reviewed By: hfinkel, jmorse

Subscribers: jmorse, javed.absar, eraman, kcc, bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363046 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-11 10:37:20 +00:00
Florian Hahn
6a170699ae [LV] Remove the redundant using LoopVectorizationPlanner:VPlanPtr
VPlan.h already contains the declaration of VPlanPtr type alias:

using VPlanPtr = std::unique_ptr<VPlan>;

The LoopVectorizationPlanner class also contains the same declaration
of VPlanPtr and therefore LoopVectorize requires a long wording when
its methods return VPlanPtr:

    LoopVectorizationPlanner::VPlanPtr
    LoopVectorizationPlanner::buildVPlanWithVPRecipes(...)

but LoopVectorize.cpp includes VPlan.h (via LoopVectorizationPlanner.h)
and can use VPlanPtr from that header.

Patch by Pavel Samolysov.

Reviewers: hsaito, rengolin, fhahn

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D62576

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362126 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-30 18:46:13 +00:00
Craig Topper
8c0b3da9d4 [LoopVectorize] Add FNeg instruction support
Differential Revision: https://reviews.llvm.org/D62510

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362124 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-30 18:19:35 +00:00
Simon Pilgrim
79e92fbf63 LoopVectorizationCostModel::selectInterleaveCount - assert we have a non-zero loop cost. NFCI.
The input LoopCost value can be zero, but if so it should be recalculated with the current VF. After that it should always be non-zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@361387 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-22 14:18:17 +00:00
Florian Hahn
75b2eadb06 [LV] Move getScalarizationOverhead and vector call cost computations to CM. (NFC)
This reduces the number of parameters we need to pass in and they seem a
natural fit in LoopVectorizationCostModel. Also simplifies things for
D59995.

As a follow up refactoring, we could only expose a expose a
shouldUseVectorIntrinsic() helper in LoopVectorizationCostModel, instead
of calling getVectorCallCost/getVectorIntrinsicCost in
InnerLoopVectorizer/VPRecipeBuilder.

Reviewers: Ayal, hsaito, dcaballe, rengolin

Reviewed By: rengolin

Differential Revision: https://reviews.llvm.org/D61638

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360758 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-15 10:05:49 +00:00
Alina Sbirlea
c419d3f938 [MemorySSA] Teach LoopSimplify to preserve MemorySSA.
Summary:
Preserve MemorySSA in LoopSimplify, in the old pass manager, if the analysis is available.
Do not preserve it in the new pass manager.
Update tests.

Subscribers: nemanjai, jlebar, javed.absar, Prazek, kbarton, zzheng, jsji, llvm-commits, george.burgess.iv, chandlerc

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60833

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360270 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-08 17:05:36 +00:00
Kostya Serebryany
53dcce4331 revert r360162 as it breaks most of the buildbots
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360190 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-07 20:57:11 +00:00
Orlando Cazalet-Hyams
8c101025dc [DebugInfo@O2][LoopVectorize] pr39024: Vectorized code linenos step through loop even after completion
Summary:
Bug: https://bugs.llvm.org/show_bug.cgi?id=39024

The bug reports that a vectorized loop is stepped through 4 times and each step through the loop seemed to show a different path. I found two problems here:

A) An incorrect line number on a preheader block (for.body.preheader) instruction causes a step into the loop before it begins.
B) Instructions in the middle block have different line numbers which give the impression of another iteration.

In this patch I give all of the middle block instructions the line number of the scalar loop latch terminator branch. This seems to provide the smoothest debugging experience because the vectorized loops will always end on this line before dropping into the scalar loop. To solve problem A I have altered llvm::SplitBlockPredecessors to accommodate loop header blocks.

Reviewers: samsonov, vsk, aprantl, probinson, anemet, hfinkel

Reviewed By: hfinkel

Subscribers: bjope, jmellorcrummey, hfinkel, gbedwell, hiraditya, zzheng, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D60831

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360162 91177308-0d34-0410-b5e6-96231b3b80d8
2019-05-07 15:37:38 +00:00
Alina Sbirlea
6ac87016ff Enable LoopVectorization by default.
Summary:
When refactoring vectorization flags, vectorization was disabled by default in the new pass manager.
This patch re-enables is for both managers, and changes the assumptions opt makes, based on the new defaults.
Comments in opt.cpp should clarify the intended use of all flags to enable/disable vectorization.

Reviewers: chandlerc, jgorbe

Subscribers: jlebar, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61091

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359167 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-25 04:49:48 +00:00
Alina Sbirlea
a837603c47 [NewPassManager] Adding pass tuning options: loop vectorize.
Summary:
Trying to add the plumbing necessary to add tuning options to the new pass manager.
Testing with the flags for loop vectorize.

Reviewers: chandlerc

Subscribers: sanjoy, mehdi_amini, jlebar, steven_wu, dexonsmith, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59723

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358763 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-19 16:11:59 +00:00
Hiroshi Yamauchi
7716d65968 [PGO] Profile guided code size optimization.
Summary:
Enable some of the existing size optimizations for cold code under PGO.

A ~5% code size saving in big internal app under PGO.

The way it gets BFI/PSI is discussed in the RFC thread

http://lists.llvm.org/pipermail/llvm-dev/2019-March/130894.html 

Note it doesn't currently touch loop passes.

Reviewers: davidxl, eraman

Reviewed By: eraman

Subscribers: mgorny, javed.absar, smeenai, mehdi_amini, eraman, zzheng, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59514

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358422 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-15 16:49:00 +00:00
Florian Hahn
9928b761ce [VPLAN] Minor improvement to testing and debug messages.
1. Use computed VF for stress testing.
2. If the computed VF does not produce vector code (VF smaller than 2), force VF to be 4.
3. Test vectorization of i64 data on AArch64 to make sure we generate VF != 4 (on X86 that was already tested on AVX).

Patch by Francesco Petrogalli <francesco.petrogalli@arm.com>

Differential Revision: https://reviews.llvm.org/D59952

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358056 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-10 08:17:28 +00:00
Evandro Menezes
d71ea05ab7 [IR] Refactor attribute methods in Function class (NFC)
Rename the functions that query the optimization kind attributes.

Differential revision: https://reviews.llvm.org/D60287

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357731 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-04 22:40:06 +00:00
Vedant Kumar
3bc14040b5 [DebugInfo] Fix pr41180 : Loop Vectorization Debugify Failure
Bug: https://bugs.llvm.org/show_bug.cgi?id=41180

In the bug test case the debug location was missing for the cmp instruction in
the "middle block" BB. This patch fixes the bug by copying the debug location
from the cmp of the scalar loop's terminator branch, if it exists.

The patch also fixes the debug location on the subsequent branch instruction.
It was previously using the location of the of the original loop's pre-header
block terminator. Both of these instructions will now map to the source line of
the conditional branch in the original loop.

A regression test has been added that covers these issues.

Patch by Orlando Cazalet-Hyams!

Differential Revision: https://reviews.llvm.org/D59944

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357499 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-02 17:28:34 +00:00
Benjamin Kramer
6ec2ba75e9 Make helper functions static. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357187 91177308-0d34-0410-b5e6-96231b3b80d8
2019-03-28 17:18:42 +00:00
Florian Hahn
3259337afd [VPlan] Determine Vector Width programmatically.
With this change, the VPlan native path is triggered with the directive:

   #pragma clang loop vectorize(enable)

There is no need to specify the vectorize_width(N) clause.

Patch by Francesco Petrogalli <francesco.petrogalli@arm.com>

Differential Revision: https://reviews.llvm.org/D57598

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@357156 91177308-0d34-0410-b5e6-96231b3b80d8
2019-03-28 10:37:12 +00:00
Sanjoy Das
2d9ad10711 Reland "Relax constraints for reduction vectorization"
Change from original commit: move test (that uses an X86 triple) into the X86
subdirectory.

Original description:
Gating vectorizing reductions on *all* fastmath flags seems unnecessary;
`reassoc` should be sufficient.

Reviewers: tvvikram, mkuper, kristof.beyls, sdesmalen, Ayal

Reviewed By: sdesmalen

Subscribers: dcaballe, huntergr, jmolloy, mcrosier, jlebar, bixia, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57728

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355889 91177308-0d34-0410-b5e6-96231b3b80d8
2019-03-12 01:31:44 +00:00
Sanjoy Das
5b9ba1171e Revert "Relax constraints for reduction vectorization"
This reverts commit r355868.  Breaks hexagon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355873 91177308-0d34-0410-b5e6-96231b3b80d8
2019-03-11 22:37:31 +00:00
Sanjoy Das
ceec6f23cb Relax constraints for reduction vectorization
Summary:
Gating vectorizing reductions on *all* fastmath flags seems unnecessary;
`reassoc` should be sufficient.

Reviewers: tvvikram, mkuper, kristof.beyls, sdesmalen, Ayal

Reviewed By: sdesmalen

Subscribers: dcaballe, huntergr, jmolloy, mcrosier, jlebar, bixia, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57728

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355868 91177308-0d34-0410-b5e6-96231b3b80d8
2019-03-11 21:36:41 +00:00
Alina Sbirlea
7c0006da85 [MemorySSA & LoopPassManager] Add remaining book keeping [NFCI].
Add plumbing to get MemorySSA in the remaining loop passes.
Also update unit test to add the dependency.
[EnableMSSALoopDependency remains disabled].

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353901 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-12 23:48:02 +00:00
Florian Hahn
04a78b6099 [LV] Remove unnecessary assignment to UserIC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353469 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-07 21:23:37 +00:00
Florian Hahn
6bed14d8a4 [LV] Prevent interleaving if computeMaxVF returned None.
As discussed in D57382, interleaving should be avoided if computeMaxVF
returns None, same as we currently do for vectorization.

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=6477

Reviewers: Ayal, dcaballe, hsaito, mkuper, rengolin

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D57837

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353461 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-07 20:49:10 +00:00
James Y Knight
3bab951f0f [opaque pointer types] Pass value type to GetElementPtr creation.
This cleans up all GetElementPtr creation in LLVM to explicitly pass a
value type rather than deriving it from the pointer's element-type.

Differential Revision: https://reviews.llvm.org/D57173

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352913 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-01 20:44:47 +00:00
James Y Knight
6c00b3f35f [opaque pointer types] Pass value type to LoadInst creation.
This cleans up all LoadInst creation in LLVM to explicitly pass the
value type rather than deriving it from the pointer's element-type.

Differential Revision: https://reviews.llvm.org/D57172

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352911 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-01 20:44:24 +00:00
Mircea Trofin
06831ab511 [llvm] Clarify responsiblity of some of DILocation discriminator APIs
Summary:
Renamed setBaseDiscriminator to cloneWithBaseDiscriminator, to match
similar APIs. Also changed its behavior to copy over the other
discriminator components, instead of eliding them.

Renamed cloneWithDuplicationFactor to
cloneByMultiplyingDuplicationFactor, which more closely matches what
this API does.

Reviewers: dblaikie, wmi

Reviewed By: dblaikie

Subscribers: zzheng, llvm-commits

Differential Revision: https://reviews.llvm.org/D56220

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351996 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-24 00:10:25 +00:00
Hideki Saito
6866f6ea0e [LV][VPlan] Change to implement VPlan based predication for
VPlan-native path

Context: Patch Series #2 for outer loop vectorization support in LV
using VPlan. (RFC:
http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html).

Patch series #2 checks that inner loops are still trivially lock-step
among all vector elements. Non-loop branches are blindly assumed as
divergent.

Changes here implement VPlan based predication algorithm to compute
predicates for blocks that need predication. Predicates are computed
for the VPLoop region in reverse post order. A block's predicate is
computed as OR of the masks of all incoming edges. The mask for an
incoming edge is computed as AND of predecessor block's predicate and
either predecessor's Condition bit or NOT(Condition bit) depending on
whether the edge from predecessor block to the current block is true
or false edge.

Reviewers: fhahn, rengolin, hsaito, dcaballe

Reviewed By: fhahn

Patch by Satish Guggilla, thanks!

Differential Revision: https://reviews.llvm.org/D53349



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351990 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-23 22:43:12 +00:00
Chandler Carruth
6b547686c5 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351636 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-19 08:50:56 +00:00
Mircea Trofin
001ab10906 [llvm] API for encoding/decoding DWARF discriminators.
Summary:
Added a pair of APIs for encoding/decoding the 3 components of a DWARF discriminator described in http://lists.llvm.org/pipermail/llvm-dev/2016-October/106532.html: the base discriminator, the duplication factor (useful in profile-guided optimization) and the copy index (used to identify copies of code in cases like loop unrolling)

The encoding packs 3 unsigned values in 32 bits. This CL addresses 2 issues:
- communicates overflow back to the user
- supports encoding all 3 components together. Current APIs assume a sequencing of events. For example, creating a new discriminator based on an existing one by changing the base discriminator was not supported.

Reviewers: davidxl, danielcdh, wmi, dblaikie

Reviewed By: dblaikie

Subscribers: zzheng, dmgreen, aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D55681

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349973 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-21 22:48:50 +00:00
Michael Kruse
6b71eaac0a [LoopVectorize] Rename pass options. NFC.
Rename:
NoUnrolling to InterleaveOnlyWhenForced
and
AlwaysVectorize to !VectorizeOnlyWhenForced

Contrary to what the name 'AlwaysVectorize' suggests, it does not
unconditionally vectorize all loops, but applies a cost model to
determine whether vectorization is profitable to all loops. Hence,
passing false will disable the cost model, except when a loop is marked
with llvm.loop.vectorize.enable. The 'OnlyWhenForced' suffix (suggested
by @hfinkel in D55716) better matches this behavior.

Similarly, 'NoUnrolling' disables the profitability cost model for
interleaving (a term to distinguish it from unrolling by the
LoopUnrollPass); rename it for consistency.

Differential Revision: https://reviews.llvm.org/D55785

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349513 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-18 17:46:09 +00:00
Michael Kruse
9a395de086 [Unroll/UnrollAndJam/Vectorizer/Distribute] Add followup loop attributes.
When multiple loop transformation are defined in a loop's metadata, their order of execution is defined by the order of their respective passes in the pass pipeline. For instance, e.g.

    #pragma clang loop unroll_and_jam(enable)
    #pragma clang loop distribute(enable)

is the same as

    #pragma clang loop distribute(enable)
    #pragma clang loop unroll_and_jam(enable)

and will try to loop-distribute before Unroll-And-Jam because the LoopDistribute pass is scheduled after UnrollAndJam pass. UnrollAndJamPass only supports one inner loop, i.e. it will necessarily fail after loop distribution. It is not possible to specify another execution order. Also,t the order of passes in the pipeline is subject to change between versions of LLVM, optimization options and which pass manager is used.

This patch adds 'followup' attributes to various loop transformation passes. These attributes define which attributes the resulting loop of a transformation should have. For instance,

    !0 = !{!0, !1, !2}
    !1 = !{!"llvm.loop.unroll_and_jam.enable"}
    !2 = !{!"llvm.loop.unroll_and_jam.followup_inner", !3}
    !3 = !{!"llvm.loop.distribute.enable"}

defines a loop ID (!0) to be unrolled-and-jammed (!1) and then the attribute !3 to be added to the jammed inner loop, which contains the instruction to distribute the inner loop.

Currently, in both pass managers, pass execution is in a fixed order and UnrollAndJamPass will not execute again after LoopDistribute. We hope to fix this in the future by allowing pass managers to run passes until a fixpoint is reached, use Polly to perform these transformations, or add a loop transformation pass which takes the order issue into account.

For mandatory/forced transformations (e.g. by having been declared by #pragma omp simd), the user must be notified when a transformation could not be performed. It is not possible that the responsible pass emits such a warning because the transformation might be 'hidden' in a followup attribute when it is executed, or it is not present in the pipeline at all. For this reason, this patche introduces a WarnMissedTransformations pass, to warn about orphaned transformations.

Since this changes the user-visible diagnostic message when a transformation is applied, two test cases in the clang repository need to be updated.

To ensure that no other transformation is executed before the intended one, the attribute `llvm.loop.disable_nonforced` can be added which should disable transformation heuristics before the intended transformation is applied. E.g. it would be surprising if a loop is distributed before a #pragma unroll_and_jam is applied.

With more supported code transformations (loop fusion, interchange, stripmining, offloading, etc.), transformations can be used as building blocks for more complex transformations (e.g. stripmining+stripmining+interchange -> tiling).

Reviewed By: hfinkel, dmgreen

Differential Revision: https://reviews.llvm.org/D49281
Differential Revision: https://reviews.llvm.org/D55288


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348944 91177308-0d34-0410-b5e6-96231b3b80d8
2018-12-12 17:32:52 +00:00
Florian Hahn
8f37d00cdf [VPlan] VPlan version of InterleavedAccessInfo.
This patch turns InterleaveGroup into a template with the instruction type
being a template parameter. It also adds a VPInterleavedAccessInfo class, which
only contains a mapping from VPInstructions to their respective InterleaveGroup.
As we do not have access to scalar evolution in VPlan, we can re-use
convert InterleavedAccessInfo to VPInterleavedAccess info.


Reviewers: Ayal, mssimpso, hfinkel, dcaballe, rengolin, mkuper, hsaito

Reviewed By: rengolin

Differential Revision: https://reviews.llvm.org/D49489


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346758 91177308-0d34-0410-b5e6-96231b3b80d8
2018-11-13 15:58:18 +00:00
Simon Pilgrim
789879d5be [CostModel] Add more realistic SK_ExtractSubvector generic costs.
Instead of defaulting to a cost = 1, expand to element extract/insert like we do for other shuffles.

This exposes an issue in LoopVectorize which could call SK_ExtractSubvector with a scalar subvector type.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346656 91177308-0d34-0410-b5e6-96231b3b80d8
2018-11-12 14:25:23 +00:00
Ayal Zaks
6d0de65682 [LV] Avoid vectorizing loops under opt for size that involve SCEV checks
Fix PR39417, PR39497

The loop vectorizer may generate runtime SCEV checks for overflow and stride==1
cases, leading to execution of original scalar loop. The latter is forbidden
when optimizing for size. An assert introduced in r344743 triggered the above
PR's showing it does happen. This patch fixes this behavior by preventing
vectorization in such cases.

Differential Revision: https://reviews.llvm.org/D53612


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345959 91177308-0d34-0410-b5e6-96231b3b80d8
2018-11-02 09:16:12 +00:00
Dorit Nuzman
06bac6c858 [LV] Support vectorization of interleave-groups that require an epilog under
optsize using masked wide loads 

Under Opt for Size, the vectorizer does not vectorize interleave-groups that
have gaps at the end of the group (such as a loop that reads only the even
elements: a[2*i]) because that implies that we'll require a scalar epilogue
(which is not allowed under Opt for Size). This patch extends the support for
masked-interleave-groups (introduced by D53011 for conditional accesses) to
also cover the case of gaps in a group of loads; Targets that enable the
masked-interleave-group feature don't have to invalidate interleave-groups of
loads with gaps; they could now use masked wide-loads and shuffles (if that's
what the cost model selects).

Reviewers: Ayal, hsaito, dcaballe, fhahn

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D53668



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345705 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-31 09:57:56 +00:00
Simon Pilgrim
38ad550dd9 [TTI] Fix uses of SK_ExtractSubvector shuffle costs (PR39368)
Correct costings of SK_ExtractSubvector requires the SubTy argument to indicate the type/size of the extracted subvector.

Unlike the rest of the shuffle kinds this means that the main Ty argument represents the source vector type not the destination!

I've done my best to fix a number of vectorizer uses:

SLP - the reduction epilogue costs should be using a SK_PermuteSingleSrc shuffle as these all occur at the hardware vector width - we're not extracting (illegal) subvector types. This is causing the cost model diffs as SK_ExtractSubvector costs are poorly handled and tend to just return 1 at the moment.

LV - I'm not clear on what the SK_ExtractSubvector should represents for recurrences - I've used a <1 x ?> subvector extraction as that seems to match the VF delta.

Differential Revision: https://reviews.llvm.org/D53573

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345617 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-30 18:10:02 +00:00
Jonas Paulsson
ccd4f446eb [LoopVectorizer] Fix for cost values of memory accesses.
This commit is a combination of two patches:

* "Fix in getScalarizationOverhead()"

   If target returns false in TTI.prefersVectorizedAddressing(), it means the
   address registers will not need to be extracted. Therefore, there should
   be no operands scalarization overhead for a load instruction.

* "Don't pass the instruction pointer from getMemInstScalarizationCost."

   Since VF is always > 1, this is a cost query for an instruction in the
   vectorized loop and it should not be evaluated within the scalar
   context of the instruction.

Review: Ulrich Weigand, Hal Finkel
https://reviews.llvm.org/D52351
https://reviews.llvm.org/D52417

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345603 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-30 14:34:15 +00:00
Dorit Nuzman
63aae622d8 [LV] Don't have fold-tail under optsize invalidate interleave-groups when
masked-interleaving is enabled

Enable interleave-groups under fold-tail scenario for Opt for size compilation;
D50480 added support for vectorizing loops of arbitrary trip-count without a
remiander, which in turn makes everything in the loop conditional, including
interleave-groups if any. It therefore invalidated all interleave-groups
because we didn't have support for vectorizing predicated interleaved-groups
at the time. In the meantime, D53011 introduced this support, so we don't
have to invalidate interleave-groups when masked-interleaved support is enabled.

Reviewers: Ayal, hsaito, dcaballe, fhahn

Reviewed By: hsaito

Differential Revision: https://reviews.llvm.org/D53559



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345115 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-24 07:11:38 +00:00
Dorit Nuzman
e7a92994d4 Leftover bits from https://reviews.llvm.org/D53420 that were accidentally left
out of revision 344883



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345021 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-23 11:51:55 +00:00
Dorit Nuzman
c7a8ddb849 [IAI,LV] Avoid creating a scalar epilogue due to gaps in interleave-groups when
optimizing for size

LV is careful to respect -Os and not to create a scalar epilog in all cases
(runtime tests, trip-counts that require a remainder loop) except for peeling
due to gaps in interleave-groups. This patch fixes that; -Os will now have us
invalidate such interleave-groups and vectorize without an epilog.

The patch also removes a related FIXME comment that is now obsolete, and was
also inaccurate:
"FIXME: return None if loop requiresScalarEpilog(<MaxVF>), or look for a smaller
MaxVF that does not require a scalar epilog."
(requiresScalarEpilog() has nothing to do with VF).

Reviewers: Ayal, hsaito, dcaballe, fhahn

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D53420



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344883 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-22 06:17:09 +00:00
Ayal Zaks
9e75857c92 [LV] Fold tail by masking to vectorize loops of arbitrary trip count under opt for size
When optimizing for size, a loop is vectorized only if the resulting vector loop
completely replaces the original scalar loop. This holds if no runtime guards
are needed, if the original trip-count TC does not overflow, and if TC is a
known constant that is a multiple of the VF. The last two TC-related conditions
can be overcome by
1. rounding the trip-count of the vector loop up from TC to a multiple of VF;
2. masking the vector body under a newly introduced "if (i <= TC-1)" condition.

The patch allows loops with arbitrary trip counts to be vectorized under -Os,
subject to the existing cost model considerations. It also applies to loops with
small trip counts (under -O2) which are currently handled as if under -Os.

The patch does not handle loops with reductions, live-outs, or w/o a primary
induction variable, and disallows interleave groups.

(Third, final and main part of -)
Differential Revision: https://reviews.llvm.org/D50480


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344743 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-18 15:03:15 +00:00
Anna Thomas
c2874102cb [LV] Teach vectorizer about variant value store into uniform address
Summary:
Teach vectorizer about vectorizing variant value stores to uniform
address. Similar to rL343028, we do not allow vectorization if we have
multiple stores to the same uniform address.

Cost model already has the change for considering the extract
instruction cost for a variant value store. See added test cases for how
vectorization is done.
The patch also contains changes to the ORE messages.

Reviewers: Ayal, mkuper, anemet, hsaito

Subscribers: rkruppe, llvm-commits

Differential Revision: https://reviews.llvm.org/D52656

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344613 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-16 15:46:26 +00:00
Ayal Zaks
631cfd79b3 [LV] Fix comments reported when not vectorizing single iteration loops; NFC
Landing this as a separate part of https://reviews.llvm.org/D50480, being a
seemingly unrelated change ([LV] Vectorizing loops of arbitrary trip count
without remainder under opt for size).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344483 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-14 17:53:02 +00:00