18 Commits

Author SHA1 Message Date
Simon Pilgrim
563ff5441e [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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354790 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-25 15:42:02 +00:00
Michael Kruse
0bb9e7af42 Refactor setAlreadyUnrolled() and setAlreadyVectorized().
Loop::setAlreadyUnrolled() and
LoopVectorizeHints::setLoopAlreadyUnrolled() both add loop metadata that
stops the same loop from being transformed multiple times. This patch
merges both implementations.

In doing so we fix 3 potential issues:

 * setLoopAlreadyUnrolled() kept the llvm.loop.vectorize/interleave.*
   metadata even though it will not be used anymore. This already caused
   problems such as http://llvm.org/PR40546. Change the behavior to the
   one of setAlreadyUnrolled which deletes this loop metadata.

 * setAlreadyUnrolled() used to create a new LoopID by calling
   MDNode::get with nullptr as the first operand, then replacing it by
   the returned references using replaceOperandWith. It is possible
   that MDNode::get would instead return an existing node (due to
   de-duplication) that then gets modified. To avoid, use a fresh
   TempMDNode that does not get uniqued with anything else before
   replacing it with replaceOperandWith.

 * LoopVectorizeHints::matchesHintMetadataName() only compares the
   suffix of the attribute to set the new value for. That is, when
   called with "enable", would erase attributes such as
   "llvm.loop.unroll.enable", "llvm.loop.vectorize.enable" and
   "llvm.loop.distribute.enable" instead of the one to replace.
   Fortunately, function was only called with "isvectorized".

Differential Revision: https://reviews.llvm.org/D57566

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353738 91177308-0d34-0410-b5e6-96231b3b80d8
2019-02-11 19:45:44 +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
Sanjay Patel
d4e1d2f774 [LoopVectorizer] give more advice in remark about failure to vectorize call
Something like this is requested by:
https://bugs.llvm.org/show_bug.cgi?id=40265
...and it seems like a common enough case that we should acknowledge it.

Differential Revision: https://reviews.llvm.org/D56551


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351010 91177308-0d34-0410-b5e6-96231b3b80d8
2019-01-12 15:27:15 +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
Anna Thomas
0048f91a87 [LV] Avoid vectorizing unsafe dependencies in uniform address
Summary:
Currently, when vectorizing stores to uniform addresses, the only
instance we prevent vectorization is if there are multiple stores to the
same uniform address causing an unsafe dependency.
This patch teaches LAA to avoid vectorizing loops that have an unsafe
cross-iteration dependency between a load and a store to the same uniform address.

Fixes PR39653.

Reviewers: Ayal, efriedma

Subscribers: rkruppe, llvm-commits

Differential Revision: https://reviews.llvm.org/D54538

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@347220 91177308-0d34-0410-b5e6-96231b3b80d8
2018-11-19 15:39:59 +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
Anna Thomas
edafc389f1 [LV][LAA] Vectorize loop invariant values stored into loop invariant address
Summary:
We are overly conservative in loop vectorizer with respect to stores to loop
invariant addresses.
More details in https://bugs.llvm.org/show_bug.cgi?id=38546
This is the first part of the fix where we start with vectorizing loop invariant
values to loop invariant addresses.

This also includes changes to ORE for stores to invariant address.

Reviewers: anemet, Ayal, mkuper, mssimpso

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50665

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343028 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-25 20:57:20 +00:00
Warren Ristow
99ea666c23 [Loop Vectorizer] Abandon vectorization when no integer IV found
Support for vectorizing loops with secondary floating-point induction
variables was added in r276554.  A primary integer IV is still required
for vectorization to be done.  If an FP IV was found, but no integer IV
was found at all (primary or secondary), the attempt to vectorize still
went forward, causing a compiler-crash.  This change abandons that
attempt when no integer IV is found.  (Vectorizing FP-only cases like
this, rather than bailing out, is discussed as possible future work
in D52327.)

See PR38800 for more information.

Differential Revision: https://reviews.llvm.org/D52327


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342786 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-21 23:03:50 +00:00
Hideki Saito
a858f4fe0b [VPlan] Implement initial vector code generation support for simple outer loops.
Summary:
[VPlan] Implement vector code generation support for simple outer loops.

Context: Patch Series #1 for outer loop vectorization support in LV  using VPlan. (RFC: http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html).
                                                          
This patch introduces vector code generation support for simple outer loops that are currently supported in the VPlanNativePath. Changes here essentially do the following:

  - force vector code generation using explicit vectorize_width

  - add conservative early returns in cost model and other places for VPlanNativePath

  - add code for setting up outer loop inductions 

  - support for widening non-induction PHIs that can result from inner loops and uniform conditional branches

  - support for generating uniform inner branches

We plan to add a handful C outer loop executable tests once the initial code generation support is committed. This patch is expected to be NFC for the inner loop vectorizer path. Since we are moving in the direction of supporting outer loop vectorization in LV, it may also be time to rename classes such as InnerLoopVectorizer. 

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

Reviewed By: fhahn, hsaito

Subscribers: dmgreen, bollu, tschuett, rkruppe, rogfer01, llvm-commits

Differential Revision: https://reviews.llvm.org/D50820

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342197 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-14 00:36:00 +00:00
Anna Thomas
099d4ece4f [LV] Vectorize loops where non-phi instructions used outside loop
Summary:
Follow up change to rL339703, where we now vectorize loops with non-phi
instructions used outside the loop. Note that the cyclic dependency
identification occurs when identifying reduction/induction vars.

We also need to identify that we do not allow users where the PSCEV information
within and outside the loop are different. This was the fix added in rL307837
for PR33706.

Reviewers: Ayal, mkuper, fhahn

Subscribers: javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D50778

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340278 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-21 14:40:27 +00:00
Anna Thomas
a3fdc1d293 NFC: Clarify comment in loop vectorization legality
Clarifying the comment about PSCEV and external IV users by referencing
the bug in question.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339722 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-14 20:25:13 +00:00
Anna Thomas
1464f16217 [LV] Teach about non header phis that have uses outside the loop
Summary:
This patch teaches the loop vectorizer to vectorize loops with non
header phis that have have outside uses.  This is because the iteration
dependence distance for these phis can be widened upto VF (similar to
how we do for induction/reduction) if they do not have a cyclic
dependence with header phis. When identifying reduction/induction/first
order recurrence header phis, we already identify if there are any cyclic
dependencies that prevents vectorization.

The vectorizer is taught to extract the last element from the vectorized
phi and update the scalar loop exit block phi to contain this extracted
element from the vector loop.

This patch can be extended to vectorize loops where instructions other
than phis have outside uses.

Reviewers: Ayal, mkuper, mssimpso, efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50579

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339703 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-14 18:22:19 +00:00
Nicola Zaghen
0818e789cb Rename DEBUG macro to LLVM_DEBUG.
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332240 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-14 12:53:11 +00:00
Adrian Prantl
26b584c691 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331272 91177308-0d34-0410-b5e6-96231b3b80d8
2018-05-01 15:54:18 +00:00
Hideki Saito
8784c51c37 [NFC][LV][LoopUtil] Move LoopVectorizationLegality to its own file
Summary:
This is a follow up to D45420 (included here since it is still under review and this change is dependent on that) and D45072 (committed).
Actual change for this patch is LoopVectorize* and cmakefile. All others are all from D45420.

LoopVectorizationLegality is an analysis and thus really belongs to Analysis tree. It is modular enough and it is reusable enough ---- we can further improve those aspects once uses outside of LV picks up.

Hopefully, this will make it easier for people familiar with vectorization theory, but not necessarily LV itself to contribute, by lowering the volume of code they should deal with. We probably should start adding some code in LV to check its own capability (i.e., vectorization is legal but LV is not ready to handle it) and then bail out.


Reviewers: rengolin, fhahn, hfinkel, mkuper, aemerson, mssimpso, dcaballe, sguggill

Reviewed By: rengolin, dcaballe

Subscribers: egarcia, rogfer01, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D45552

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331139 91177308-0d34-0410-b5e6-96231b3b80d8
2018-04-29 07:26:18 +00:00