Commit Graph

314 Commits

Author SHA1 Message Date
Kazu Hirata 5d1ae6346b [Analysis] Teach getOptionalIntLoopAttribute to return std::optional (NFC)
This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-11-19 15:36:50 -08:00
Florian Hahn 16cf666bb7
[Loop] Move block and loop dispo invalidation to makeLoopInvariant.
makeLoopInvariant may recursively move its operands to make them
invariant, before moving the passed in instruction. Those recursively
moved instructions are currently missed when invalidating block and loop
dispositions.

To address this, move the invalidation code to Loop::makeLoopInvariant.

Fixes #58314.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D135909
2022-10-14 21:58:14 +01:00
Nikita Popov 534b9246a2 [LoopInfo] Allow cloning of callbr
After D129288, callbr is safe to clone without special handling.
This permits optimizations like loop unroll and loop unswitch on
loops containing callbrs.

Fixes https://github.com/llvm/llvm-project/issues/41834.

Differential Revision: https://reviews.llvm.org/D129993
2022-07-19 09:57:28 +02:00
Max Kazantsev 51f837a680 [NFC] Introduce API to detect tokens penetrating LCSSA form
Following discussion in PR56243, we need to somehow detect the situation
when token values penetrate LCSSA form for transforms that require that
it is maintained by all values (for example, to sustain use-def dominance
invarians). This patch introduces a parameter to LCSSA checkers to control
their ignorance about tokens.

Differential Revision: https://reviews.llvm.org/D129983
Reviewed By: efriedma
2022-07-19 13:52:30 +07:00
Kazu Hirata 129b531c9c [llvm] Use value_or instead of getValueOr (NFC) 2022-06-18 23:07:11 -07:00
Martin Storsjö 46776f7556 Fix warnings about variables that are set but only used in debug mode
Add void casts to mark the variables used, next to the places where
they are used in assert or `LLVM_DEBUG()` expressions.

Differential Revision: https://reviews.llvm.org/D123117
2022-04-06 10:01:46 +03:00
serge-sans-paille 71c3a5519d Cleanup includes: LLVMAnalysis
Number of lines output by preprocessor:
before: 1065940348
after:  1065307662

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D120659
2022-03-01 18:01:54 +01:00
William S. Moses 0d04c77856 [ScalarEvolution] Mark a loop as finite if in a willreturn function
A limited version of (https://reviews.llvm.org/D118090) that only marks a loop as finite if in a willreturn function.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D118429
2022-01-28 14:17:05 -05:00
Kazu Hirata b752eb887f [Analysis] Use default member initialization (NFC)
Identified with modernize-use-default-member-init.
2022-01-23 20:32:56 -08:00
duanbo.db 53dc525828 [LoopInfo] Fix function getInductionVariable
The way function gets the induction variable is by judging whether
StepInst or IndVar in the phi statement is one of the operands of CMP.
But if the LatchCmpOp0/LatchCmpOp1 is a constant,  the subsequent
comparison may result in null == null, which is meaningless. This patch
fixes the typo.

Reviewed By: Whitney

Differential Revision: https://reviews.llvm.org/D112980
2021-11-11 16:22:42 +08:00
Michael Kruse 650bbc5620 [OpenMP][OpenMPIRBuilder] Implement loop unrolling.
Recommit of 707ce34b06. Don't introduce a
dependency to the LLVMPasses component, instead register the required
passes individually.

Add methods for loop unrolling to the OpenMPIRBuilder class and use them in Clang if `-fopenmp-enable-irbuilder` is enabled. The unrolling methods are:

 * `unrollLoopFull`
 * `unrollLoopPartial`
 * `unrollLoopHeuristic`

`unrollLoopPartial` and `unrollLoopHeuristic` can use compiler heuristics to automatically determine the unroll factor. If possible, that is if no CanonicalLoopInfo is required to pass to another method, metadata for LLVM's LoopUnrollPass is added. Otherwise the unroll factor is determined using the same heurstics as user by LoopUnrollPass. Not requiring a CanonicalLoopInfo, especially with `unrollLoopHeuristic` allows greater flexibility.

With full unrolling and partial unrolling with known unroll factor, instead of duplicating instructions by the OpenMPIRBuilder, the full unroll is still delegated to the LoopUnrollPass. In case of partial unrolling the loop is first tiled using the existing `tileLoops` methods, then the inner loop fully unrolled using the same mechanism.

Reviewed By: jdoerfert, kiranchandramohan

Differential Revision: https://reviews.llvm.org/D107764
2021-09-04 19:18:58 -05:00
Roman Lebedev 50634deaa5
Revert "[OpenMP][OpenMPIRBuilder] Implement loop unrolling."
Breaks build with -DBUILD_SHARED_LIBS=ON
```
CMake Error: The inter-target dependency graph contains the following strongly connected component (cycle):
  "LLVMFrontendOpenMP" of type SHARED_LIBRARY
    depends on "LLVMPasses" (weak)
  "LLVMipo" of type SHARED_LIBRARY
    depends on "LLVMFrontendOpenMP" (weak)
  "LLVMCoroutines" of type SHARED_LIBRARY
    depends on "LLVMipo" (weak)
  "LLVMPasses" of type SHARED_LIBRARY
    depends on "LLVMCoroutines" (weak)
    depends on "LLVMipo" (weak)
At least one of these targets is not a STATIC_LIBRARY.  Cyclic dependencies are allowed only among static libraries.
CMake Generate step failed.  Build files cannot be regenerated correctly.
```

This reverts commit 707ce34b06.
2021-09-02 12:42:23 +03:00
Michael Kruse 707ce34b06 [OpenMP][OpenMPIRBuilder] Implement loop unrolling.
Add methods for loop unrolling to the OpenMPIRBuilder class and use them in Clang if `-fopenmp-enable-irbuilder` is enabled. The unrolling methods are:

 * `unrollLoopFull`
 * `unrollLoopPartial`
 * `unrollLoopHeuristic`

`unrollLoopPartial` and `unrollLoopHeuristic` can use compiler heuristics to automatically determine the unroll factor. If possible, that is if no CanonicalLoopInfo is required to pass to another method, metadata for LLVM's LoopUnrollPass is added. Otherwise the unroll factor is determined using the same heurstics as user by LoopUnrollPass. Not requiring a CanonicalLoopInfo, especially with `unrollLoopHeuristic` allows greater flexibility.

With full unrolling and partial unrolling with known unroll factor, instead of duplicating instructions by the OpenMPIRBuilder, the full unroll is still delegated to the LoopUnrollPass. In case of partial unrolling the loop is first tiled using the existing `tileLoops` methods, then the inner loop fully unrolled using the same mechanism.

Reviewed By: jdoerfert, kiranchandramohan

Differential Revision: https://reviews.llvm.org/D107764
2021-09-02 02:37:25 -05:00
Rosie Sumpter 44c9adb414 [LoopFlatten][LoopInfo] Use Loop to identify latch compare instruction
Make getLatchCmpInst non-static and use it in LoopFlatten as a more
robust way of identifying the compare.

Differential Revision: https://reviews.llvm.org/D106256
2021-07-21 10:14:18 +01:00
Philip Reames 7629b2a09c [LI] Add a cover function for checking if a loop is mustprogress [nfc]
Essentially, the cover function simply combines the loop level check and the function level scope into one call.  This simplifies several callers and is (subjectively) less error prone.
2021-06-10 13:37:32 -07:00
Philip Reames b6ee5f2b1d Move code for checking loop metadata into Analysis [nfc]
I need the mustprogress loop metadata in ScalarEvolution and it makes sense to keep all the accessors for quering loop metadate together.
2021-06-10 13:01:22 -07:00
Whitney Tsang 1006ac3963 [LoopNest] Consider loop nest with inner loop guard using outer loop
induction variable to be perfect

This patch allow more conditional branches to be considered as loop
guard, and so more loop nests can be considered perfect.

Reviewed By: bmahjour, sidbav

Differential Revision: https://reviews.llvm.org/D94717
2021-05-07 16:04:18 +00:00
Arthur Eubanks c8f0a7c215 [NewPM] Cleanup IR printing instrumentation
Being lazy with printing the banner seems hard to reason with, we should print it
unconditionally first (it could also lead to duplicate banners if we
have multiple functions in -filter-print-funcs).

The printIR() functions were doing too many things. I separated out the
call from PrintPassInstrumentation since we were essentially doing two
completely separate things in printIR() from different callers.

There were multiple ways to generate the name of some IR. That's all
been moved to getIRName(). The printing of the IR name was also
inconsistent, now it's always "IR Dump on $foo" where "$foo" is the
name. For a function, it's the function name. For a loop, it's what's
printed by Loop::print(), which is more detailed. For an SCC, it's the
list of functions in parentheses. For a module it's "[module]", to
differentiate between a possible SCC with a function called "module".

To preserve D74814, we have to check if we're going to print anything at
all first. This is unfortunate, but I would consider this a special
case that shouldn't be handled in the core logic.

Reviewed By: jamieschmeiser

Differential Revision: https://reviews.llvm.org/D100231
2021-04-15 09:50:55 -07:00
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