Setting -fvisibility=hidden when compiling Target libs has the advantage of
not being intrusive on the codebase, but it also sets the visibility of all
functions within header-only component like ADT. In the end, we end up with
some symbols with hidden visibility within llvm dylib (through the target libs),
and some with external visibility (through other libs). This paves the way for
subtle bugs like https://reviews.llvm.org/D101972
This patch explicitly set the visibility of some classes to `default` so that
`llvm::Any` related symbols keep a `default` visibility. Indeed a template
function with `default` visibility parametrized by a type with `hidden`
visibility is granted `hidden` visibility, and we don't want this for the
uniqueness of `llvm::Any::TypeId`.
Differential Revision: https://reviews.llvm.org/D108943
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
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.
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
Currently, LoopDeletion refuses to remove dead loops with no exit blocks
because it cannot statically determine the control flow after it removes
the block. This leads to miscompiles if the loop is an infinite loop and
should've been removed.
Differential Revision: https://reviews.llvm.org/D90115
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
An irreducible SCC is one which has multiple "header" blocks, i.e., blocks
with control-flow edges incident from outside the SCC. This pass converts an
irreducible SCC into a natural loop by introducing a single new header
block and redirecting all the edges on the original headers to this
new block.
This is a useful workaround for a limitation in the structurizer
which, which produces incorrect control flow in the presence of
irreducible regions. The AMDGPU backend provides an option to
enable this pass before the structurizer, which may eventually be
enabled by default.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D77198
This restores commit 2ada8e2525dd2653f30c8696a27162a3b1647d66.
Originally reverted with commit 44e09b59b869a91bf47d76e8bc569d9ee91ad145.
This reverts commit 2ada8e2525dd2653f30c8696a27162a3b1647d66.
Buildbots produced compilation errors which I was not able to quickly
reproduce locally. Need more time to investigate.
An irreducible SCC is one which has multiple "header" blocks, i.e., blocks
with control-flow edges incident from outside the SCC. This pass converts an
irreducible SCC into a natural loop by introducing a single new header
block and redirecting all the edges on the original headers to this
new block.
This is a useful workaround for a limitation in the structurizer
which, which produces incorrect control flow in the presence of
irreducible regions. The AMDGPU backend provides an option to
enable this pass before the structurizer, which may eventually be
enabled by default.
Reviewed By: nhaehnle
Differential Revision: https://reviews.llvm.org/D77198
Recently I had to use it and although one assumes it returns null if
there's no parent loop, I think it helps to doc it.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D74890
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.
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
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
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
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
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
I've noticed a lot of confusion around this area recently with key terms being misused in a number of threads. To help reign that in, let's go ahead and document the current terminology and meaning thereof.
My hope is to grow this over time into a broader discussion of canonical loop forms - yes, there are more than one ... many more than one - but for the moment, simply having the key terminology is a good stopping place.
Note: I am landing this *without* an LGTM. All feedback so far has been positive, and trying to apply all of the suggested changes/extensions would cause the review to never end. Instead, I decided to land it with the obvious fixes made based on reviewer comments, then iterate from there.
Differential Revision: https://reviews.llvm.org/D65164
llvm-svn: 366960
It is possible that exit block has two predecessors and one of them is a latch
block while another is not.
Current algorithm is based on the assumption that all exits are dedicated
and therefore we can check only first predecessor of loop exit to find all unique
exits.
However if we do not consider latch block and it is first predecessor of some
exit then this exit will be found.
Regression test is added.
As a side effect of algorithm re-writing, the restriction that all exits are dedicated
is eliminated.
Reviewers: reames, fhahn, efriedma
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D64787
llvm-svn: 366294
Extract the code from LoopUnrollRuntime into utility function to
re-use it in D63923.
Reviewers: reames, mkuper
Reviewed By: reames
Subscribers: fhahn, hiraditya, zzheng, dmgreen, llvm-commits
Differential Revision: https://reviews.llvm.org/D64548
llvm-svn: 366040
D63921 requires getExitEdges fills a vector of Edge pairs where
BasicBlocks are not constant.
The rest Loop API mostly returns non-const BasicBlocks, so to be more consistent with
other Loop API getExitEdges is modified to return non-const BasicBlocks as well.
This is an alternative solution to D64060.
Reviewers: reames, fhahn
Reviewed By: reames, fhahn
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D64309
llvm-svn: 365437
Currently isLoopExiting returns true for BBs that are not part of the
loop. To avoid hiding subtle bugs, this patch adds an assertion to make
sure the passed BB is inside the loop
Reviewers: reames, efriedma, hfinkel, arsenm, nhaehnle
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D63952
llvm-svn: 365077
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
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
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
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
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
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
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
llvm-svn: 331272
By checking that none of the child loops contain a BB we make sure BBMap
contains the innermost loop defining BB. This invariant was violated in
LoopInterchange and got caught by this assertion.
Reviewers: chandlerc, mzolotukhin, sanjoy, mehdi_amini, efriedma
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D45971
llvm-svn: 330698
making it no longer even remotely simple.
The pass will now be more of a "full loop unswitching" pass rather than
anything substantively simpler than any other approach. I plan to rename
it accordingly once the dust settles.
The key ideas of the new loop unswitcher are carried over for
non-trivial unswitching:
1) Fully unswitch a branch or switch instruction from inside of a loop to
outside of it.
2) Update the CFG and IR. This avoids needing to "remember" the
unswitched branches as well as avoiding excessively cloning and
reliance on complex parts of simplify-cfg to cleanup the cfg.
3) Update the analyses (where we can) rather than just blowing them away
or relying on something else updating them.
Sadly, #3 is somewhat compromised here as the dominator tree updates
were too complex for me to want to reason about. I will need to make
another attempt to do this now that we have a nice dynamic update API
for dominators. However, we do adhere to #3 w.r.t. LoopInfo.
This approach also adds an important principls specific to non-trivial
unswitching: not *all* of the loop will be duplicated when unswitching.
This fact allows us to compute the cost in terms of how much *duplicate*
code is inserted rather than just on raw size. Unswitching conditions
which essentialy partition loops will work regardless of the total loop
size.
Some remaining issues that I will be addressing in subsequent commits:
- Handling unstructured control flow.
- Unswitching 'switch' cases instead of just branches.
- Moving to the dynamic update API for dominators.
Some high-level, interesting limitationsV that folks might want to push
on as follow-ups but that I don't have any immediate plans around:
- We could be much more clever about not cloning things that will be
deleted. In fact, we should be able to delete *nothing* and do
a minimal number of clones.
- There are many more interesting selection criteria for which branch to
unswitch that we might want to look at. One that I'm interested in
particularly are a set of conditions which all exit the loop and which
can be merged into a single unswitched test of them.
Differential revision: https://reviews.llvm.org/D34200
llvm-svn: 318549
This avoid code duplication and allow us to add the disable unroll metadata elsewhere.
Differential Revision: https://reviews.llvm.org/D38928
llvm-svn: 315850
The second argument for Allocator::Deallocate is the number of elements,
not the size of a single element. In asan mode specifying a large number
of elements poisoned random memory regions, leading to crashes
everywhere.
llvm-svn: 314413
Summary:
And now that we no longer have to explicitly free() the Loop instances, we can
(with more ease) use the destructor of LoopBase to do what LoopBase::clear() was
doing.
Reviewers: chandlerc
Subscribers: mehdi_amini, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D38201
llvm-svn: 314375
Summary:
With this change:
- Methods in LoopBase trip an assert if the receiver has been invalidated
- LoopBase::clear frees up the memory held the LoopBase instance
This change also shuffles things around as necessary to work with this stricter invariant.
Reviewers: chandlerc
Subscribers: mehdi_amini, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D38055
llvm-svn: 313708
