Summary:
This is unfortunately needed for correctness, if we are to extend the tolerance of the update API to the way simple loop unswitch is doing cloning.
In simple loop unswitch (as opposed to loop unswitch), not all blocks are cloned. This can create unreachable cloned blocks (no predecessor), which are later cleaned up.
In MemorySSA, the APIs for supporting these kind of updates (clone + update exit blocks), make certain assumption on the integrity of the CFG. When cloning, if something was not cloned, it's values in MemorySSA default to LiveOnEntry. When updating exit blocks, it is safe to assume that we can first insert phis in the blocks merging two clones, then add additional phis in the IDF of the blocks that received phis. This no longer holds true if one of the clones being merged comes from an unreachable block. We'd conservatively need to add all phis before filling in their incoming definitions. In practice this restriction can be relaxed if we clean up trivial phis after the first round of insertion.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63354
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363880 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When computing IDF for insert updates, ensure we use the snapshot CFG offered by GraphDiff.
Caught by D63389.
Reviewers: kuhar, george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits, Szelethus
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63443
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363879 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
LoopRotate doesn't create a faithful clone of an instruction, it may
simplify it beforehand. Hence the clone of an instruction that has a
MemoryDef associated may not be a definition, but a use or not a memory
alternig instruction.
Don't rely on the template when the clone may be simplified.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63355
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363597 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Add all MemoryPhis in IDF before filling in their incomign values.
Otherwise, a new Phi can be added that needs to become the incoming
value of another Phi.
Test fails the verification in verifyPrevDefInPhis.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, zzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63353
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363590 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: After applying a set of insert updates, there may be trivial Phis left over. Clean them up.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63033
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363094 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360270 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Originally the insertDef method was only used when building MemorySSA, and was limiting the number of Phi nodes that it created.
Now it's used for updates as well, and it can create additional Phis needed for correctness.
Make sure no Phis are created in unreachable blocks (condition met during MSSA build), otherwise the renamePass will find a null DTNode.
Resolves PR41640.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61410
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359845 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: Create a method to clean up multiple potentially trivial phis, since we will need this often.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61471
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359842 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When inserting a new Def, MemorySSA may be have non-minimal number of Phis.
While inserting, the walk to find the previous definition may cleanup minimal Phis.
When the last definition is trivial to obtain, we do not cache it.
It is possible while getting the previous definition for a Def to get two different answers:
- one that was straight-forward to find when walking the first path (a trivial phi in this case), and
- another that follows a cleanup of the trivial phi, it determines it may need additional Phi nodes, it inserts them and returns a new phi in the same position as the former trivial one.
While the Phis added for the second path are all redundant, they are not complete (the walk is only done upwards), and they are not properly cleaned up afterwards.
A way to fix this problem is to cache the straight-forward answer we got on the first walk.
The caching is only kept for the duration of a getPreviousDef call, and for Phis we use TrackingVH, so removing the trivial phi will lead to replacing it with the next dominating phi in the cache.
Resolves PR40749.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60634
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358313 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The original assumption for the insertDef method was that it would not
materialize Defs out of no-where, hence it will not insert phis needed
after inserting a Def.
However, when cloning an instruction (use case used in LICM), we do
materialize Defs "out of no-where". If the block receiving a Def has at
least one other Def, then no processing is needed. If the block just
received its first Def, we must check where Phi placement is needed.
The only new usage of insertDef is in LICM, hence the trigger for the bug.
But the original goal of the method also fails to apply for the move()
method. If we move a Def from the entry point of a diamond to either the
left or right blocks, then the merge block must add a phi.
While this usecase does not currently occur, or may be viewed as an
incorrect transformation, MSSA must behave corectly given the scenario.
Resolves PR40749 and PR40754.
Reviewers: george.burgess.iv
Subscribers: sanjoy, jlebar, Prazek, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58652
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355040 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
EarlyCSE needs to optimize MemoryPhis after an access is removed and has
special handling for it. This should be handled by MemorySSA instead.
The default remains that MemoryPhis are *not* optimized after an access
is removed.
Reviewers: george.burgess.iv
Subscribers: sanjoy, jlebar, llvm-commits, Prazek
Differential Revision: https://reviews.llvm.org/D57199
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352787 91177308-0d34-0410-b5e6-96231b3b80d8
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
Add methods to BasicBlock which make it easier to efficiently check
whether a block has N (or more) predecessors.
This can be more efficient than using pred_size(), which is a linear
time operation.
We might consider adding similar methods for successors. I haven't done
so in this patch because succ_size() is already O(1).
With this patch applied, I measured a 0.065% compile-time reduction in
user time for running `opt -O3` on the sqlite3 amalgamation (30 trials).
The change in mergeStoreIntoSuccessor alone saves 45 million linked list
iterations in a stage2 Release build of llc.
See llvm.org/PR39702 for a harder but more general way of achieving
similar results.
Differential Revision: https://reviews.llvm.org/D54686
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@347256 91177308-0d34-0410-b5e6-96231b3b80d8
by `getTerminator()` calls instead be declared as `Instruction`.
This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344502 91177308-0d34-0410-b5e6-96231b3b80d8
Fix for https://bugs.llvm.org/show_bug.cgi?id=38807, which occurred
while compiling SemaTemplateInstantiate.cpp with clang and GVNHoist
enabled. In the following example:
1=def(entry)
/ \
2=def(1) 4=def(1)
3=def(2) 5=def(4)
When removing the MemoryDef 2=def(1) from its basic block, and just
before adding it to the end of the parent basic block, we first
replace all its uses with the defining memory access:
3=def(2) -> 3=def(1)
Then we call insertDef for adding 2=def(1) to the parent basic block,
where we replace the uses of 1=def(entry) with 2=def(1). Doing so we
create a self reference:
2=def(1) -> 2=def(2) (bad)
3=def(1) -> 3=def(2) (ok)
4=def(1) -> 4=def(2) (ok)
Differential Revision: https://reviews.llvm.org/D51801
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341947 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
End goal is to update MemorySSA in all loop passes. LoopUnswitch clones all blocks in a loop. SimpleLoopUnswitch clones some blocks. LoopRotate clones some instructions.
Some of these loop passes also make CFG changes.
This is an API based on what I found needed in LoopUnswitch, SimpleLoopUnswitch, LoopRotate, LoopInstSimplify, LoopSimplifyCFG.
Adding dependent patches using this API for context.
Reviewers: george.burgess.iv, dberlin
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D45299
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341855 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Block splitting is done with either identical edges being merged, or not.
Only critical edges can be split without merging identical edges based on an option.
Teach the memoryssa updater to take this into account: for the same edge between two blocks only move one entry from the Phi in Old to the new Phi in New.
Reviewers: george.burgess.iv
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D51563
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341709 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@340698 91177308-0d34-0410-b5e6-96231b3b80d8
Bug fix for PR37445. The underlying problem and its fix are similar to PR37808.
The bug lies in MemorySSAUpdater::getPreviousDefRecursive(), where PhiOps is
computed before the call to tryRemoveTrivialPhi() and it ends up being out of
date, pointing to stale data. We have now turned each of the PhiOps into a
TrackingVH<MemoryAccess>.
Differential Revision: https://reviews.llvm.org/D49425
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337680 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
When splitting predecessors in BasicBlockUtils, we create a new block as an immediate predecessor of the original BB, then we connect a given set of predecessors to the new block.
The API in this patch will be used to update MemoryPhis for this CFG change.
If all predecessors are being moved, we move the MemoryPhi directly. Otherwise we create a new MemoryPhi in the NewBB and populate its incoming values, while deleting them from BB's Phi.
[Split from D45299 for easier review]
Reviewers: george.burgess.iv
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D49156
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337581 91177308-0d34-0410-b5e6-96231b3b80d8
Bug fix for PR37808. The regression test is a reduced version of the
original reproducer attached to the bug report. As stated in the report,
the problem was that InsertedPHIs was keeping dangling pointers to
deleted Memory-Phis. MemoryPhis are created eagerly and sometimes get
zapped shortly afterwards. I've used WeakVH instead of an expensive
removal operation from the active workset.
Differential Revision: https://reviews.llvm.org/D48372
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337149 91177308-0d34-0410-b5e6-96231b3b80d8
For the first one, we dereference `NewDef` right before the `if` anyway.
For the second, we shouldn't have NULL users().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336952 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The move APIs added in this patch will be used to update MemorySSA when CFG changes merge or split blocks, by moving memory accesses accordingly in MemorySSA's internal data structures.
[Split from D45299 for easier review]
Reviewers: george.burgess.iv
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D48897
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336860 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
MemoryPhis now have APIs analogous to BB Phis to remove an incoming value/block.
The MemorySSAUpdater uses the above APIs when updating MemorySSA given a set of dead blocks about to be deleted.
Reviewers: george.burgess.iv
Subscribers: sanjoy, jlebar, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D48396
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336015 91177308-0d34-0410-b5e6-96231b3b80d8
Style guide says `else`s after returns are iffy, and I agree. I also
don't know what broke the comments here and in CFLAA, but *shrug*.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@333332 91177308-0d34-0410-b5e6-96231b3b80d8
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
Fix PR36484, as suggested:
<quote>
during moves, mark the direct users of the erased things that were phis as "not to be optimized"
<quote>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329621 91177308-0d34-0410-b5e6-96231b3b80d8
MemorySSAUpdater::getPreviousDefRecursive is a recursive algorithm, for
each block, it computes the previous definition for each predecessor,
then takes those definitions and combines them. But currently it doesn't
remember results which it already computed; this means it can visit the
same block multiple times, which adds up to exponential time overall.
To fix this, this patch adds a cache. If we computed the result for a
block already, we don't need to visit it again because we'll come up
with the same result. Well, unless we RAUW a MemoryPHI; in that case,
the TrackingVH will be updated automatically.
This matches the original source paper for this algorithm.
The testcase isn't really a test for the bug, but it adds coverage for
the case where tryRemoveTrivialPhi erases an existing PHI node. (It's
hard to write a good regression test for a performance issue.)
Differential Revision: https://reviews.llvm.org/D44715
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328577 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Check that the first access before one being tested is valid.
Before this patch, if there was no definition prior to the Use being tested,
the first time Iter was deferenced, it hit the sentinel.
Reviewers: dberlin, gbiv
Subscribers: sanjoy, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D33950
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304926 91177308-0d34-0410-b5e6-96231b3b80d8
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304787 91177308-0d34-0410-b5e6-96231b3b80d8
- Mark an internal function static
- Remove the llvm namespace (just holding on to the `using namespace
llvm;` Works on My Machine(TM))
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300947 91177308-0d34-0410-b5e6-96231b3b80d8
Analysis, it has Analysis passes, and once NewGVN is made an Analysis,
this removes the cross dependency from Analysis to Transform/Utils.
NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299980 91177308-0d34-0410-b5e6-96231b3b80d8
