The test case requires the peeled loop to be forgotten after peeling,
even though it does not have a parent. When called via the unroller,
SE->forgetTopmostLoop is also called, so the test case would also pass
without any SCEV invalidation, but peelLoop is exposed as utility
function. Also, in the test case, simplifyLoop will make changes,
removing the loop from SCEV, but it is better to not rely on this
behavior.
Reviewers: sanjoy, mkazantsev
Reviewed By: mkazantsev
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58192
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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
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
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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
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For Hexagon, peeling loops with small runtime trip count is beneficial for our
benchmarks. We set PeelCount in HexagonTargetInfo.cpp and we use PeelCount set
by the target for computing the desired peel count.
Differential Revision: https://reviews.llvm.org/D44880
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For Hexagon, peeling loops with small runtime trip count is beneficial for our
benchmarks. We set PeelCount in HexagonTargetInfo.cpp and we use PeelCount set
by the target for computing the desired peel count.
Differential Revision: https://reviews.llvm.org/D44880
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We check `canPeel` twice: when evaluating the number of iterations to be peeled
and within the method `peelLoop` that performs peeling. This method is only
executed if the calculated peel count is positive. Thus, the check in `peelLoop` can
never fail. This patch replaces this check with an assert.
Differential Revision: https://reviews.llvm.org/D44919
Reviewed By: fhahn
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If the loop body contains conditions of the form IndVar < #constant, we
can remove the checks by peeling off #constant iterations.
This improves codegen for PR34364.
Reviewers: mkuper, mkazantsev, efriedma
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D43876
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Removes verifyDomTree, using assert(verify()) everywhere instead, and
changes verify a little to always run IsSameAsFreshTree first in order
to print good output when we find errors. Also adds verifyAnalysis for
PostDomTrees, which will allow checking of PostDomTrees it the same way
we check DomTrees and MachineDomTrees.
Differential Revision: https://reviews.llvm.org/D41298
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Summary:
This replaces calls to getEntryCount().hasValue() with hasProfileData
that does the same thing. This refactoring is useful to do before adding
synthetic function entry counts but also a useful cleanup IMO even
otherwise. I have used hasProfileData instead of hasRealProfileData as
David had earlier suggested since I think profile implies "real" and I
use the phrase "synthetic entry count" and not "synthetic profile count"
but I am fine calling it hasRealProfileData if you prefer.
Reviewers: davidxl, silvas
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41461
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This patch is a generalization of the improvement introduced in rL296898.
Previously, we were able to peel one iteration of a loop to get rid of a Phi that becomes
an invariant on the 2nd iteration. In more general case, if a Phi becomes invariant after
N iterations, we can peel N times and turn it into invariant.
In order to do this, we for every Phi in loop's header we define the Invariant Depth value
which is calculated as follows:
Given %x = phi <Inputs from above the loop>, ..., [%y, %back.edge].
If %y is a loop invariant, then Depth(%x) = 1.
If %y is a Phi from the loop header, Depth(%x) = Depth(%y) + 1.
Otherwise, Depth(%x) is infinite.
Notice that if we peel a loop, all Phis with Depth = 1 become invariants,
and all other Phis with finite depth decrease the depth by 1.
Thus, peeling N first iterations allows us to turn all Phis with Depth <= N
into invariants.
Reviewers: reames, apilipenko, mkuper, skatkov, anna, sanjoy
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31613
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When peeling loops basing on phis becoming invariants, we make a wrong loop size check.
UP.Threshold should be compared against the total numbers of instructions after the transformation,
which is equal to 2 * LoopSize in case of peeling one iteration.
We should also check that the maximum allowed number of peeled iterations is not zero.
Reviewers: sanjoy, anna, reames, mkuper
Reviewed By: mkuper
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31753
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Summary:
We should check if loop size allows us to peel at least one iteration
before we do so.
Patch by Max Kazantsev!
Reviewers: sanjoy, mkuper, efriedma
Reviewed By: mkuper
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30632
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Summary:
If a loop contains a Phi node which has an invariant input from back
edge, it is profitable to peel such loops (rather than unroll them) to
use the advantage that this Phi is always invariant starting from 2nd
iteration. After the 1st iteration is peeled, other optimizations can
potentially simplify calculations with this invariant.
Patch by Max Kazantsev!
Reviewers: sanjoy, apilipenko, igor-laevsky, anna, mkuper, reames
Reviewed By: mkuper
Subscribers: mkuper, mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D30161
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Summary:
In current implementation the loop peeling happens after trip-count based partial unrolling and may
sometimes not happen at all due to it (for example, if trip count is known, but UP.Partial = false). This
is generally bad, the more than there are some situations where peeling is profitable even if the partial
unrolling is disabled.
This patch is a NFC which reorders peeling and partial unrolling application and prepares the code for
implementation of the said optimizations.
Patch by Max Kazantsev!
Reviewers: sanjoy, anna, reames, apilipenko, igor-laevsky, mkuper
Reviewed By: mkuper
Subscribers: mkuper, llvm-commits, mzolotukhin
Differential Revision: https://reviews.llvm.org/D30243
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Mostly straightforward changes; we just didn't do the computation before.
One sort of interesting change in LoopUnroll.cpp: we weren't handling
dominance for children of the loop latch correctly, but
foldBlockIntoPredecessor hid the problem for complete unrolling.
Currently punting on loop peeling; made some minor changes to isolate
that problem to LoopUnrollPeel.cpp.
Adds a flag -unroll-verify-domtree; it verifies the domtree immediately
after we finish updating it. This is on by default for +Asserts builds.
Differential Revision: https://reviews.llvm.org/D28073
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Summary:
Regardless how the loop body weight is distributed, we should preserve
total loop body weight. i.e. we should have same weight reaching the body of the loop
or its duplicates in peeled and unpeeled case.
Reviewers: mkuper, davidxl, anemet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28179
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This implements PGO-driven loop peeling.
The basic idea is that when the average dynamic trip-count of a loop is known,
based on PGO, to be low, we can expect a performance win by peeling off the
first several iterations of that loop.
Unlike unrolling based on a known trip count, or a trip count multiple, this
doesn't save us the conditional check and branch on each iteration. However,
it does allow us to simplify the straight-line code we get (constant-folding,
etc.). This is important given that we know that we will usually only hit this
code, and not the actual loop.
This is currently disabled by default.
Differential Revision: https://reviews.llvm.org/D25963
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