18 Commits

Author SHA1 Message Date
Florian Hahn
30565e0e43 [LoopUnrollAndJam] Use Lazy strategy for DTU.
We can also apply the earlier updates to the lazy DTU, instead of
applying them directly.

Reviewers: kuhar, brzycki, asbirlea, SjoerdMeijer

Reviewed By: brzycki, asbirlea, SjoerdMeijer

Differential Revision: https://reviews.llvm.org/D66918

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370391 91177308-0d34-0410-b5e6-96231b3b80d8
2019-08-29 17:47:58 +00:00
Alina Sbirlea
798b89ee1e [Utils] Clean another duplicated util method.
Summary:
Following the cleanup in D48202, method foldBlockIntoPredecessor has the
same behavior. Replace its uses with MergeBlockIntoPredecessor.
Remove foldBlockIntoPredecessor.

Reviewers: chandlerc, dmgreen

Subscribers: jlebar, javed.absar, zzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62751

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362538 91177308-0d34-0410-b5e6-96231b3b80d8
2019-06-04 18:45:15 +00:00
Alina Sbirlea
3a08fe1789 [SCEV] Add option to forget everything in SCEV.
Summary:
Create a method to forget everything in SCEV.
Add a cl::opt and PassManagerBuilder option to use this in LoopUnroll.

Motivation: Certain Halide applications spend a very long time compiling in forgetLoop, and prefer to forget everything and rebuild SCEV from scratch.
Sample difference in compile time reduction: 21.04 to 14.78 using current ToT release build.
Testcase showcasing this cannot be opensourced and is fairly large.

The option disabled by default, but it may be desirable to enable by
default. Evidence in favor (two difference runs on different days/ToT state):

File Before (s) After (s)
clang-9.bc 7267.91 6639.14
llvm-as.bc 194.12 194.12
llvm-dis.bc 62.50 62.50
opt.bc 1855.85 1857.53

File Before (s) After (s)
clang-9.bc 8588.70 7812.83
llvm-as.bc 196.20 194.78
llvm-dis.bc 61.55 61.97
opt.bc 1739.78 1886.26

Reviewers: sanjoy

Subscribers: mehdi_amini, jlebar, zzheng, javed.absar, dmgreen, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60144

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358304 91177308-0d34-0410-b5e6-96231b3b80d8
2019-04-12 19:16:07 +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
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
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
Max Kazantsev
288477a949 [NFC] Make LoopSafetyInfo abstract to allow alternative implementations
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344592 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-16 08:31:05 +00:00
Chandler Carruth
2aaf7228e0 [TI removal] Make variables declared as TerminatorInst and initialized
by `getTerminator()` calls instead be declared as `Instruction`.

This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344502 91177308-0d34-0410-b5e6-96231b3b80d8
2018-10-15 10:04:59 +00:00
David Green
a5f4d29929 [UnJ] Rename hasInvariantIterationCount to hasIterationCountInvariantInParent NFC
This hopefully describes the API of the function more precisely.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339762 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-15 10:59:41 +00:00
Max Kazantsev
d823f47a68 [NFC] Refactoring of LoopSafetyInfo, step 1
Turn structure into class, encapsulate methods, add clarifying comments.

Differential Revision: https://reviews.llvm.org/D50693
Reviewed By: reames


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339752 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-15 05:55:43 +00:00
David Green
d2a6b5951c [UnJ] Create a hasInvariantIterationCount function. NFC
Pulled out a separate function for some code that calculates
if an inner loop iteration count is invariant to it's outer
loop.

Differential Revision: https://reviews.llvm.org/D50063


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339500 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-11 06:57:28 +00:00
David Green
f166ea7ca2 [UnJ] Add debug messages for why loops are not unrolled. NFC
Adds some cleaned up debug messages from back when I was writing this.
Hopefully useful to others (and myself) as to why unroll and jam is not
transforming as expected.

Differential Revision: https://reviews.llvm.org/D50062


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338676 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-02 07:30:53 +00:00
David Green
0b19d8a7b1 [UnJ] Common some code. NFC
Create a processHeaderPhiOperands for analysing the instructions
in the aft blocks that must be moved before the loop.

Differential Revision: https://reviews.llvm.org/D49061



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338033 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-26 15:19:07 +00:00
David Green
ecc246961c [UnJ] Use SmallPtrSets for block collections. NFC
We no longer care about the order of blocks in these collections,
so can change to SmallPtrSets, making contains checks quicker.

Differential revision: https://reviews.llvm.org/D49060



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336897 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-12 10:44:47 +00:00
David Green
e101271f21 [UnrollAndJam] New Unroll and Jam pass
This is a simple implementation of the unroll-and-jam classical loop
optimisation.

The basic idea is that we take an outer loop of the form:

  for i..
    ForeBlocks(i)
    for j..
      SubLoopBlocks(i, j)
    AftBlocks(i)

Instead of doing normal inner or outer unrolling, we unroll as follows:

  for i... i+=2
    ForeBlocks(i)
    ForeBlocks(i+1)
    for j..
      SubLoopBlocks(i, j)
      SubLoopBlocks(i+1, j)
    AftBlocks(i)
    AftBlocks(i+1)
  Remainder Loop

So we have unrolled the outer loop, then jammed the two inner loops into
one. This can lead to a simpler inner loop if memory accesses can be shared
between the now jammed loops.

To do this we have to prove that this is all safe, both for the memory
accesses (using dependence analysis) and that ForeBlocks(i+1) can move before
AftBlocks(i) and SubLoopBlocks(i, j).

Differential Revision: https://reviews.llvm.org/D41953



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336062 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-01 12:47:30 +00:00
David Green
00d34a85c6 Revert 333358 as it's failing on some builders.
I'm guessing the tests reply on the ARM backend being built.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333359 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-27 12:54:33 +00:00
David Green
3dde46793c [UnrollAndJam] Add a new Unroll and Jam pass
This is a simple implementation of the unroll-and-jam classical loop
optimisation.

The basic idea is that we take an outer loop of the form:

for i..
  ForeBlocks(i)
  for j..
    SubLoopBlocks(i, j)
  AftBlocks(i)

Instead of doing normal inner or outer unrolling, we unroll as follows:

for i... i+=2
  ForeBlocks(i)
  ForeBlocks(i+1)
  for j..
    SubLoopBlocks(i, j)
    SubLoopBlocks(i+1, j)
  AftBlocks(i)
  AftBlocks(i+1)
Remainder

So we have unrolled the outer loop, then jammed the two inner loops into
one. This can lead to a simpler inner loop if memory accesses can be shared
between the now-jammed loops.

To do this we have to prove that this is all safe, both for the memory
accesses (using dependence analysis) and that ForeBlocks(i+1) can move before
AftBlocks(i) and SubLoopBlocks(i, j).

Differential Revision: https://reviews.llvm.org/D41953



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333358 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-27 12:11:21 +00:00