Commit Graph

296 Commits

Author SHA1 Message Date
Philip Reames 31764ea295 [LCSSA] Extract a utility for deciding if a new use requires a new lcssa phi [NFC]
(Triggered by a review comment on D98728, but otherwise unrelated.)
2021-03-17 12:14:01 -07:00
Kazu Hirata 896d0e1a2a [Analysis] Use range-based for loops (NFC) 2021-02-22 20:17:18 -08:00
Kazu Hirata 910e2d1e57 [llvm] Use llvm::is_contained (NFC) 2021-02-14 08:36:20 -08:00
Kazu Hirata 28d3132089 [Analysis] Use range-based for loops (NFC) 2021-02-06 11:17:10 -08:00
Kazu Hirata 23b0ab2acb [llvm] Use the default value of drop_begin (NFC) 2021-01-18 10:16:36 -08:00
Arthur Eubanks 2f0de58294 [NewPM] Support --print-before/after in NPM
This changes --print-before/after to be a list of strings rather than
legacy passes. (this also has the effect of not showing the entire list
of passes in --help-hidden after --print-before/after, which IMO is
great for making it less verbose).

Currently PrintIRInstrumentation passes the class name rather than pass
name to llvm::shouldPrintBeforePass(), meaning
llvm::shouldPrintBeforePass() never functions as intended in the NPM.
There is no easy way of converting class names to pass names outside of
within an instance of PassBuilder.

This adds a map of pass class names to their short names in
PassRegistry.def within PassInstrumentationCallbacks. It is populated
inside the constructor of PassBuilder, which takes a
PassInstrumentationCallbacks.

Add a pointer to PassInstrumentationCallbacks inside
PrintIRInstrumentation and use the newly created map.

This is a bit hacky, but I can't think of a better way since the short
id to class name only exists within PassRegistry.def. This also doesn't
handle passes not in PassRegistry.def but rather added via
PassBuilder::registerPipelineParsingCallback().

llvm/test/CodeGen/Generic/print-after.ll doesn't seem very useful now
with this change.

Reviewed By: ychen, jamieschmeiser

Differential Revision: https://reviews.llvm.org/D87216
2020-12-03 16:52:14 -08:00
Atmn Patel cea0599aa7 [LangRef] Adds llvm.loop.mustprogress loop metadata
This patch adds the llvm.loop.mustprogress loop metadata. This is to be
added to loops where the frontend language requires that the loop makes
observable interactions with the environment. This is the loop-level
equivalent to the function attribute `mustprogress` defined in D86233.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D88464
2020-11-04 22:32:50 -05:00
Stefanos Baziotis a3345300b6 [LCSSA] Doc for special treatment of PHIs
Differential Revision: https://reviews.llvm.org/D89739
2020-10-29 22:50:07 +02:00
Duncan P. N. Exon Smith d4c667c9af Avoid unnecessary uses of `MDNode::getTemporary`, NFC
This is a long-delayed follow-up to
5e5b85098d.

`TempMDNode` includes a bunch of machinery for RAUW, and should only be
used when necessary. RAUW wasn't being used in any of these cases... it
was just a placeholder for a self-reference.

Where the real node was using `MDNode::getDistinct`, just replace the
temporary argument with `nullptr`.

Where the real node was using `MDNode::get`, the `replaceOperandWith`
call was "promoting" the node to a distinct one implicitly due to
self-reference detection in `MDNode::handleChangedOperand`. The
`TempMDNode` was serving a purpose by delaying uniquing, but it's way
simpler to just call `MDNode::getDistinct` in the first place.

Note that using a self-reference at all in these places is a hold-over
from before `distinct` metadata existed. It was an old trick to create
distinct nodes. It would be intrusive to change, including bitcode
upgrades, etc., and it's harmless so I'm not sure there's much value in
removing it from existing schemas. After this commit it still has a tiny
memory cost (in the extra metadata operand) but no more overhead in
construction.

Differential Revision: https://reviews.llvm.org/D90079
2020-10-26 17:03:25 -04:00
Stefanos Baziotis 89c1e35f3c [LoopInfo] empty() -> isInnermost(), add isOutermost()
Differential Revision: https://reviews.llvm.org/D82895
2020-09-22 23:28:51 +03:00
Max Kazantsev 72c13446ce [NFC] Add missing 'const' notion to LCSSA-related functions
These functions don't really do any changes to loop info or
dominator tree. We should state this explicitly using 'const'.
2020-04-17 17:49:34 +07:00
Mircea Trofin 447e2c3067 [llvm][NFC][CallSite] Remove Implementation uses of CallSite
Reviewers: dblaikie, davidxl, craig.topper

Subscribers: arsenm, dschuff, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78142
2020-04-14 14:49:47 -07:00
Kit Barton 61368c8e98 Rename LoopInfo::isRotated() to LoopInfo::isRotatedForm().
This patch renames the LoopInfo::isRotated() method to LoopInfo::isRotatedForm()
to make it clear that the method checks whether the loop is in rotated form, not
whether the loop has been rotated by the LoopRotation pass.
2019-12-12 14:22:36 -05:00
Fangrui Song 25e21a09b3 Fix -Wunused-variable in -DLLVM_ENABLE_ASSERTIONS=Off builds after D65958 and D70450 2019-12-11 11:04:03 -08:00
Kit Barton 942c9946cc [Loop] Add isRotated method to Loop class.
Summary:
This patch adds a method to determine if a loop is in rotated form (the latch is
an exiting block). It also modifies the getLoopGuardBranch method to use this
new method. This method can also be used in Loopfusion. Once this patch lands I
will make the corresponding changes there.

Reviewers: jdoerfert, Meinersbur, dmgreen, etiotto, Whitney, fhahn, hfinkel

Reviewed By: Meinersbur

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65958
2019-12-11 09:43:10 -05:00
Alina Sbirlea 5c5cf899ef [MemorySSA] Moving at the end often means before terminator.
Moving accesses in MemorySSA at InsertionPlace::End, when an instruction is
moved into a block, almost always means insert at the end of the block, but
before the block terminator. This matters when the block terminator is a
MemoryAccess itself (an invoke), and the insertion must be done before
the terminator for the update to be correct.

Insert an additional position: InsertionPlace:BeforeTerminator and update
current usages where this applies.

Resolves PR44027.
2019-11-20 17:11:00 -08:00
Reid Kleckner 05da2fe521 Sink all InitializePasses.h includes
This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.

I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
  recompiles    touches affected_files  header
  342380        95      3604    llvm/include/llvm/ADT/STLExtras.h
  314730        234     1345    llvm/include/llvm/InitializePasses.h
  307036        118     2602    llvm/include/llvm/ADT/APInt.h
  213049        59      3611    llvm/include/llvm/Support/MathExtras.h
  170422        47      3626    llvm/include/llvm/Support/Compiler.h
  162225        45      3605    llvm/include/llvm/ADT/Optional.h
  158319        63      2513    llvm/include/llvm/ADT/Triple.h
  140322        39      3598    llvm/include/llvm/ADT/StringRef.h
  137647        59      2333    llvm/include/llvm/Support/Error.h
  131619        73      1803    llvm/include/llvm/Support/FileSystem.h

Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.

Reviewers: bkramer, asbirlea, bollu, jdoerfert

Differential Revision: https://reviews.llvm.org/D70211
2019-11-13 16:34:37 -08:00
Whitney Tsang dcb75bf843 [LOOPGUARD] Remove asserts in getLoopGuardBranch
Summary: The assertion in getLoopGuardBranch can be a 'return nullptr'
under if condition.
Authored By: DTharun
Reviewer: Whitney, fhahn
Reviewed By: Whitney, fhahn
Subscribers: fhahn, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D66084

llvm-svn: 373857
2019-10-06 16:39:43 +00:00
Wei Mi 9c8efeda5c Revert "[LoopInfo] Limit the iterations to check whether a loop has dedicated
exits"

Get a better approach in https://reviews.llvm.org/D68107 to solve the problem.
Revert the initial patch and will commit the new one soon.

This reverts commit rL372990.

llvm-svn: 373044
2019-09-27 05:43:30 +00:00
Whitney Tsang 9c5fbcf920 [LOOPGUARD] Disable loop with multiple loop exiting blocks.
Summary: As discussed in the loop group meeting. With the current
definition of loop guard, we should not allow multiple loop exiting
blocks. For loops that has multiple loop exiting blocks, we can simply
unable to find the loop guard.
When getUniqueExitBlock() obtains a vector size not equals to one, that
means there is either no exit blocks or there exists more than one
unique block the loop exit to.
If we don't disallow loop with multiple loop exit blocks, then with our
current implementation, there can exist exit blocks don't post dominated
by the non pre-header successor of the guard block.
Reviewer: reames, Meinersbur, kbarton, etiotto, bmahjour
Reviewed By: Meinersbur, kbarton
Subscribers: fhahn, hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D66529

llvm-svn: 373011
2019-09-26 20:20:42 +00:00
Wei Mi 67d93f0d91 [LoopInfo] Limit the iterations to check whether a loop has dedicated exits
for extreme large case.

We had a case that a single loop which has 4000 exits and the average number
of predecessors of each exit is > 1000, and we found compiling the case spent
a significant amount of time on checking whether a loop has dedicated exits.
This patch adds a limit for the iterations to the check. With the patch, the
time to compile our testcase reduced from 1000s to 200s (clang release build).

Differential Revision: https://reviews.llvm.org/D67359

llvm-svn: 372990
2019-09-26 15:36:25 +00:00
Whitney Tsang 8ee361ebe5 [LOOPINFO] Introduce the loop guard API.
Summary:
This is the first patch for the loop guard. We introduced
getLoopGuardBranch() and isGuarded().
This currently only works on simplified loop, as it requires a preheader
and a latch to identify the guard.
It will work on loops of the form:
/// GuardBB:
///   br cond1, Preheader, ExitSucc <== GuardBranch
/// Preheader:
///   br Header
/// Header:
///  ...
///   br Latch
/// Latch:
///   br cond2, Header, ExitBlock
/// ExitBlock:
///   br ExitSucc
/// ExitSucc:
Prior discussions leading upto the decision to introduce the loop guard
API: http://lists.llvm.org/pipermail/llvm-dev/2019-May/132607.html
Reviewer: reames, kbarton, hfinkel, jdoerfert, Meinersbur, dmgreen
Reviewed By: reames
Subscribers: wuzish, hiraditya, jsji, llvm-commits, bmahjour, etiotto
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D63885

llvm-svn: 367033
2019-07-25 16:13:18 +00:00
Evgeniy Stepanov 6abd78cc7c Make DT a transitive dependency of LI.
Summary:
LoopInfoWrapperPass::verify uses DT, which means DT must be alive
even if it has no direct users.

Fixes a crash in expensive checks mode.

Reviewers: pcc, leonardchan

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64896

llvm-svn: 366388
2019-07-17 23:31:59 +00:00
Nick Desaulniers c4f245b40a [LoopUnroll+LoopUnswitch] do not transform loops containing callbr
Summary:
There is currently a correctness issue when unrolling loops containing
callbr's where their indirect targets are being updated correctly to the
newly created labels, but their operands are not.  This manifests in
unrolled loops where the second and subsequent copies of callbr
instructions have blockaddresses of the label from the first instance of
the unrolled loop, which would result in nonsensical runtime control
flow.

For now, conservatively do not unroll the loop.  In the future, I think
we can pursue unrolling such loops provided we transform the cloned
callbr's operands correctly.

Such a transform and its legalities are being discussed in:
https://reviews.llvm.org/D64101

Link: https://bugs.llvm.org/show_bug.cgi?id=42489
Link: https://groups.google.com/forum/#!topic/clang-built-linux/z-hRWP9KqPI

Reviewers: fhahn, hfinkel, efriedma

Reviewed By: fhahn, hfinkel, efriedma

Subscribers: efriedma, hiraditya, zzheng, dmgreen, llvm-commits, pirama, kees, nathanchance, E5ten, craig.topper, chandlerc, glider, void, srhines

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64368

llvm-svn: 366130
2019-07-15 21:16:29 +00:00
Whitney Tsang 2d0896c1cb [LOOPINFO] Extend Loop object to add utilities to get the loop bounds,
step, and loop induction variable.

Summary: This PR extends the loop object with more utilities to get loop
bounds, step, and loop induction variable. There already exists passes
which try to obtain the loop induction variable in their own pass, e.g.
loop interchange. It would be useful to have a common area to get these
information.

/// Example:
/// for (int i = lb; i < ub; i+=step)
///   <loop body>
/// --- pseudo LLVMIR ---
/// beforeloop:
///   guardcmp = (lb < ub)
///   if (guardcmp) goto preheader; else goto afterloop
/// preheader:
/// loop:
///   i1 = phi[{lb, preheader}, {i2, latch}]
///   <loop body>
///   i2 = i1 + step
/// latch:
///   cmp = (i2 < ub)
///   if (cmp) goto loop
/// exit:
/// afterloop:
///
/// getBounds
///   getInitialIVValue      --> lb
///   getStepInst            --> i2 = i1 + step
///   getStepValue           --> step
///   getFinalIVValue        --> ub
///   getCanonicalPredicate  --> '<'
///   getDirection           --> Increasing
/// getInductionVariable          --> i1
/// getAuxiliaryInductionVariable --> {i1}
/// isCanonical                   --> false

Reviewers: kbarton, hfinkel, dmgreen, Meinersbur, jdoerfert, syzaara,
fhahn
Reviewed By: kbarton
Subscribers: tvvikram, bmahjour, etiotto, fhahn, jsji, hiraditya,
llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D60565

llvm-svn: 362644
2019-06-05 20:42:47 +00:00
Whitney Tsang 590b1aee60 Revert "Title: [LOOPINFO] Extend Loop object to add utilities to get the loop"
This reverts commit d34797dfc2.

llvm-svn: 362615
2019-06-05 15:32:56 +00:00
Benjamin Kramer b90b354798 [LoopInfo] Fix unused variable warning. NFC.
llvm-svn: 362610
2019-06-05 14:43:58 +00:00
Whitney Tsang d34797dfc2 Title: [LOOPINFO] Extend Loop object to add utilities to get the loop
bounds, step, and loop induction variable.

Summary: This PR extends the loop object with more utilities to get loop
bounds, step, and loop induction variable. There already exists passes
which try to obtain the loop induction variable in their own pass, e.g.
loop interchange. It would be useful to have a common area to get these
information.

/// Example:
/// for (int i = lb; i < ub; i+=step)
///   <loop body>
/// --- pseudo LLVMIR ---
/// beforeloop:
///   guardcmp = (lb < ub)
///   if (guardcmp) goto preheader; else goto afterloop
/// preheader:
/// loop:
///   i1 = phi[{lb, preheader}, {i2, latch}]
///   <loop body>
///   i2 = i1 + step
/// latch:
///   cmp = (i2 < ub)
///   if (cmp) goto loop
/// exit:
/// afterloop:
///
/// getBounds
///   getInitialIVValue      --> lb
///   getStepInst            --> i2 = i1 + step
///   getStepValue           --> step
///   getFinalIVValue        --> ub
///   getCanonicalPredicate  --> '<'
///   getDirection           --> Increasing
/// getInductionVariable          --> i1
/// getAuxiliaryInductionVariable --> {i1}
/// isCanonical                   --> false

Reviewers: kbarton, hfinkel, dmgreen, Meinersbur, jdoerfert, syzaara,
fhahn
Reviewed By: kbarton
Subscribers: tvvikram, bmahjour, etiotto, fhahn, jsji, hiraditya,
llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D60565

llvm-svn: 362609
2019-06-05 14:34:12 +00:00
Kit Barton 987fdfd9a7 Revert [LOOPINFO] Extend Loop object to add utilities to get the loop bounds, step, induction variable, and guard branch.
This reverts r361517 (git commit 2049e4dd8f)

llvm-svn: 361553
2019-05-23 20:53:05 +00:00
Kit Barton 2049e4dd8f [LOOPINFO] Extend Loop object to add utilities to get the loop bounds, step, induction variable, and guard branch.
Summary:
    This PR extends the loop object with more utilities to get loop bounds, step, induction variable, and guard branch. There already exists passes which try to obtain the loop induction variable in their own pass, e.g. loop interchange. It would be useful to have a common area to get these information. Moreover, loop fusion (https://reviews.llvm.org/D55851) is planning to use getGuard() to extend the kind of loops it is able to fuse, e.g. rotated loop with non-constant upper bound, which would have a loop guard.

      /// Example:
      /// for (int i = lb; i < ub; i+=step)
      ///   <loop body>
      /// --- pseudo LLVMIR ---
      /// beforeloop:
      ///   guardcmp = (lb < ub)
      ///   if (guardcmp) goto preheader; else goto afterloop
      /// preheader:
      /// loop:
      ///   i1 = phi[{lb, preheader}, {i2, latch}]
      ///   <loop body>
      ///   i2 = i1 + step
      /// latch:
      ///   cmp = (i2 < ub)
      ///   if (cmp) goto loop
      /// exit:
      /// afterloop:
      ///
      /// getBounds
      ///   getInitialIVValue      --> lb
      ///   getStepInst            --> i2 = i1 + step
      ///   getStepValue           --> step
      ///   getFinalIVValue        --> ub
      ///   getCanonicalPredicate  --> '<'
      ///   getDirection           --> Increasing
      /// getGuard             --> if (guardcmp) goto loop; else goto afterloop
      /// getInductionVariable          --> i1
      /// getAuxiliaryInductionVariable --> {i1}
      /// isCanonical                   --> false

    Committed on behalf of @Whitney (Whitney Tsang).

    Reviewers: kbarton, hfinkel, dmgreen, Meinersbur, jdoerfert, syzaara, fhahn

    Reviewed By: kbarton

    Subscribers: tvvikram, bmahjour, etiotto, fhahn, jsji, hiraditya, llvm-commits

    Tags: #llvm

    Differential Revision: https://reviews.llvm.org/D60565

llvm-svn: 361517
2019-05-23 17:56:35 +00:00
Alina Sbirlea f31eba6494 [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

llvm-svn: 360270
2019-05-08 17:05:36 +00:00
Keno Fischer d8f856d265 [LoopInfo] Faster implementation of setLoopID. NFC.
Summary:
This change was part of D46460. However, in the meantime rL341926 fixed the
correctness issue here. What remained was the performance issue in setLoopID
where it would iterate through all blocks in the loop and their successors,
rather than just the predecessor of the header (the later presumably being
much faster). We already have the `getLoopLatches` to compute precisely these
basic blocks in an efficient manner, so just use it (as the original commit
did for `getLoopID`).

Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D61215

llvm-svn: 359684
2019-05-01 14:39:11 +00:00
Mircea Trofin b27d0fd0bf [llvm][NFC] Factor out logic for getting incoming & back Loop edges
Reviewers: davidxl

Reviewed By: davidxl

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59967

llvm-svn: 357284
2019-03-29 17:39:17 +00:00
Michael Kruse 77a614a6e1 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

llvm-svn: 353738
2019-02-11 19:45:44 +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
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
Michael Kruse 7244852557 [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

llvm-svn: 348944
2018-12-12 17:32:52 +00:00
Chandler Carruth edb12a838a [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).

llvm-svn: 344502
2018-10-15 10:04:59 +00:00
Fedor Sergeev 662e5686fe [New PM][PassInstrumentation] IR printing support for New Pass Manager
Implementing -print-before-all/-print-after-all/-filter-print-func support
through PassInstrumentation callbacks.

- PrintIR routines implement printing callbacks.

- StandardInstrumentations class provides a central place to manage all
  the "standard" in-tree pass instrumentations. Currently it registers
  PrintIR callbacks.

Reviewers: chandlerc, paquette, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D50923

llvm-svn: 342896
2018-09-24 16:08:15 +00:00
Michael Kruse 534c87df82 [Loopinfo] Remove one latch-case in getLoopID. NFC.
getLoopID has different control flow for two cases: If there is a
single loop latch and for any other number of loop latches (0 and more
than one). The latter case should return the same result if there is
only a single latch. We can save the preceding redundant search for a
latch by handling both cases with the same code.

Differential Revision: https://reviews.llvm.org/D52118

llvm-svn: 342406
2018-09-17 18:40:29 +00:00
Johannes Doerfert a58e9214ac [LoopInfo] Fix Loop::getLoopID() for loops with multiple latches
The previous implementation traversed all loop blocks and bailed if one
was not a latch block. Since we are only interested in latch blocks, we
should only traverse those.

llvm-svn: 341926
2018-09-11 11:44:17 +00:00
Chandler Carruth 96fc1de77d [IR] Begin removal of TerminatorInst by removing successor manipulation.
The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.

The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.

Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.

This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html

There will be a series of much more mechanical changes following this
one to complete this move.

Differential Revision: https://reviews.llvm.org/D47467

llvm-svn: 340698
2018-08-26 08:41:15 +00:00
Diego Caballero 29a07b37bf [LoopInfo] Port loop exit interfaces from Loop to LoopBase
This patch ports hasDedicatedExits, getUniqueExitBlocks and
getUniqueExitBlock in Loop to LoopBase so that they can be used
from other LoopBase sub-classes.

Reviewers: chandlerc, sanjoy, hfinkel, fhahn

Reviewed By: chandlerc

Differential Revision: https://reviews.llvm.org/D48817

llvm-svn: 336572
2018-07-09 17:52:49 +00:00
Vedant Kumar e0b5f86b30 [STLExtras] Add distance() for ranges, pred_size(), and succ_size()
This commit adds a wrapper for std::distance() which works with ranges.
As it would be a common case to write `distance(predecessors(BB))`, this
also introduces `pred_size()` and `succ_size()` helpers to make that
easier to write.

Differential Revision: https://reviews.llvm.org/D46668

llvm-svn: 332057
2018-05-10 23:01:54 +00:00
Nico Weber 432a38838d IWYU for llvm-config.h in llvm, additions.
See r331124 for how I made a list of files missing the include.
I then ran this Python script:

    for f in open('filelist.txt'):
        f = f.strip()
        fl = open(f).readlines()

        found = False
        for i in xrange(len(fl)):
            p = '#include "llvm/'
            if not fl[i].startswith(p):
                continue
            if fl[i][len(p):] > 'Config':
                fl.insert(i, '#include "llvm/Config/llvm-config.h"\n')
                found = True
                break
        if not found:
            print 'not found', f
        else:
            open(f, 'w').write(''.join(fl))

and then looked through everything with `svn diff | diffstat -l | xargs -n 1000 gvim -p`
and tried to fix include ordering and whatnot.

No intended behavior change.

llvm-svn: 331184
2018-04-30 14:59:11 +00:00
Fedor Sergeev 3b459c3847 IR printing improvement for loop passes - handle -print-module-scope
Summary:
Adding support for -print-module-scope similar to how it is
being done for function passes. This option causes loop-pass printer
to emit a whole-module IR instead of just a loop itself.

Reviewers: sanjoy, silvas, weimingz

Reviewed By: sanjoy

Subscribers: apilipenko, skatkov, llvm-commits

Differential Revision: https://reviews.llvm.org/D40247

llvm-svn: 319566
2017-12-01 18:33:58 +00:00
Zachary Turner 8065f0b975 Mark all library options as hidden.
These command line options are not intended for public use, and often
don't even make sense in the context of a particular tool anyway. About
90% of them are already hidden, but when people add new options they
forget to hide them, so if you were to make a brand new tool today, link
against one of LLVM's libraries, and run tool -help you would get a
bunch of junk that doesn't make sense for the tool you're writing.

This patch hides these options. The real solution is to not have
libraries defining command line options, but that's a much larger effort
and not something I'm prepared to take on.

Differential Revision: https://reviews.llvm.org/D40674

llvm-svn: 319505
2017-12-01 00:53:10 +00:00
Fedor Sergeev 61975b49fe IR printing improvement for loop passes
Summary:
Loop-pass printing is somewhat deficient since it does not provide the
context around the loop (e.g. preheader). This context information becomes
pretty essential when analyzing transformations that move stuff out of the loop.

Extending printLoop to cover preheader and exit blocks (if any).

Reviewers: sanjoy, silvas, weimingz

Reviewed By: sanjoy

Subscribers: apilipenko, skatkov, llvm-commits

Differential Revision: https://reviews.llvm.org/D40246

llvm-svn: 318878
2017-11-22 20:59:53 +00:00
Aaron Ballman 615eb47035 Reverting r315590; it did not include changes for llvm-tblgen, which is causing link errors for several people.
Error LNK2019 unresolved external symbol "public: void __cdecl `anonymous namespace'::MatchableInfo::dump(void)const " (?dump@MatchableInfo@?A0xf4f1c304@@QEBAXXZ) referenced in function "public: void __cdecl `anonymous namespace'::AsmMatcherEmitter::run(class llvm::raw_ostream &)" (?run@AsmMatcherEmitter@?A0xf4f1c304@@QEAAXAEAVraw_ostream@llvm@@@Z) llvm-tblgen D:\llvm\2017\utils\TableGen\AsmMatcherEmitter.obj 1

llvm-svn: 315854
2017-10-15 14:32:27 +00:00
Hongbin Zheng 73f650435b [LoopInfo][Refactor] Make SetLoopAlreadyUnrolled a member function of the Loop Pass, NFC.
This avoid code duplication and allow us to add the disable unroll metadata elsewhere.

Differential Revision: https://reviews.llvm.org/D38928

llvm-svn: 315850
2017-10-15 07:31:02 +00:00