This patch aims to revert the changes introduced by D70781 D71192 D76364
D70781 was introduced to fix hardware hang where we do not insert exp-
null-done for a kill inside infinit loop. At that time we have not added
exp-null-done for kill early termination, but I believe as for now, we will
always add the exp-null-done for early termination case in LaterBranchLowering.
D71192 was introduced to handle the only_kill case, which is also been
handled by the kill early termination work.
D76364 was used to fix a regression by D71192, where we cleared the done
bit of the export in the existing program and not let the normal return
block branching to the new unified return block.
With this change, we just trust frontends have setup exp-done correctly
which is true for all existing frontends. The backend only inserts
exp-null-done for the kill cases which is handled in SILateBranchLowering.cpp.
Reviewed by: critson
Differential Revision: https://reviews.llvm.org/D105610
There is a number of transforms in SimplifyCFG that take DomTree out of
DomTreeUpdater, and do updates manually. Until they are fixed,
user passes are unable to claim that PDT is preserved.
Note that the default for SimplifyCFG is still not to preserve DomTree,
so this is still effectively NFC.
This is a (last big?) part of the patch series to make SimplifyCFG
preserve DomTree. Currently, it still does not actually preserve it,
even thought it is pretty much fully updated to preserve it.
Once the default is flipped, a valid DomTree must be passed into
simplifyCFG, which means that whatever pass calls simplifyCFG,
should also be smart about DomTree's.
As far as i can see from `check-llvm` with default flipped,
this is the last LLVM test batch (other than bugpoint tests)
that needed fixes to not break with default flipped.
The changes here are boringly identical to the ones i did
over 42+ times/commits recently already,
so while AMDGPU is outside of my normal ecosystem,
i'm going to go for post-commit review here,
like in all the other 42+ changes.
Note that while the pass is taught to preserve {,Post}DomTree,
it still doesn't do that by default, because simplifycfg
still doesn't do that by default, and flipping default
in this pass will implicitly flip the default for simplifycfg.
That will happen, but not right now.
... so just ensure that we pass DomTreeUpdater it into it.
Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.
This reverts commit 5831e86190966d58385678eb74b26aefacbfd101,
which reverted commit 90c1b0442a031d6cad686fdc4e5d3db03c3603a6
in preparation for reverting
commit b2018198c32a0535bb1f5bb5b40fbcf50d8d47b7 in
commit 1067d3e176ea7b0b1942c163bf8c6c90107768c1 due to the introducton
of a dependency cycle.
Now that the other revert is reverted with a fix, this can be relanded.
This reverts commit 90c1b0442a031d6cad686fdc4e5d3db03c3603a6.
This is based on another commit which also needs to be reverted.
The other commit introduced a Dependency Cycle between Transforms/Scalar
and TransformUtils. Scalar already depends (in many ways) on
TransformUtils, so making TransformUtils depend on Scalar should be
avoided.
Summary:
Avoid exposing details about how roots are stored. This enables subsequent
type-erasure changes.
v5:
- cleanup a unit test by using EXPECT_EQ instead of EXPECT_TRUE
Change-Id: I532b774cc71f2224e543bc7d79131d97f63f093d
Reviewers: arsenm, RKSimon, mehdi_amini, courbet
Subscribers: jvesely, wdng, hiraditya, kuhar, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83085
Summary:
For the case where "done" bits on existing exports are removed
by unifyReturnBlockSet(), unify all return blocks - even the
uniformly reached ones. We do not want to end up with a non-unified,
uniformly reached block containing a normal export with the "done"
bit cleared.
That case is believed to be rare - possible with infinite loops
in pixel shaders.
This is a fix for D71192.
Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76364
Summary:
The code was assuming in a few places that if there was only one exit
from the function that it was a normal return, which is invalid. It
could be an infinite loop, in which case we still need to insert the
usual fake edge so that the null export happens. This fixes shaders that
end with an infinite loop that discards.
Reviewers: arsenm, nhaehnle, critson
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71192
Summary:
Due to the fact that kill is just a normal intrinsic, even though it's
supposed to terminate the thread, we can end up with provably infinite
loops that are actually supposed to end successfully. The
AMDGPUUnifyDivergentExitNodes pass breaks up these loops, but because
there's no obvious place to make the loop branch to, it just makes it
return immediately, which skips the exports that are supposed to happen
at the end and hangs the GPU if all the threads end up being killed.
While it would be nice if the fact that kill terminates the thread were
modeled in the IR, I think that the structurizer as-is would make a mess if we
did that when the kill is inside control flow. For now, we just add a null
export at the end to make sure that it always exports something, which fixes
the immediate problem without penalizing the more common case. This means that
we sometimes do two "done" exports when only some of the threads enter the
discard loop, but from tests the hardware seems ok with that.
This fixes dEQP-VK.graphicsfuzz.while-inside-switch with radv.
Reviewers: arsenm, nhaehnle
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70781
Summary:
The code was assuming in a few places that if there was only one exit
from the function that it was a normal return, which is invalid. It
could be an infinite loop, in which case we still need to insert the
usual fake edge so that the null export happens. This fixes shaders that
end with an infinite loop that discards.
Reviewers: arsenm, nhaehnle, critson
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71192
Summary:
Due to the fact that kill is just a normal intrinsic, even though it's
supposed to terminate the thread, we can end up with provably infinite
loops that are actually supposed to end successfully. The
AMDGPUUnifyDivergentExitNodes pass breaks up these loops, but because
there's no obvious place to make the loop branch to, it just makes it
return immediately, which skips the exports that are supposed to happen
at the end and hangs the GPU if all the threads end up being killed.
While it would be nice if the fact that kill terminates the thread were
modeled in the IR, I think that the structurizer as-is would make a mess if we
did that when the kill is inside control flow. For now, we just add a null
export at the end to make sure that it always exports something, which fixes
the immediate problem without penalizing the more common case. This means that
we sometimes do two "done" exports when only some of the threads enter the
discard loop, but from tests the hardware seems ok with that.
This fixes dEQP-VK.graphicsfuzz.while-inside-switch with radv.
Reviewers: arsenm, nhaehnle
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70781
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
Original patch https://reviews.llvm.org/D63659 from
Steven Perron <stevenperron@google.com>
The pass AMDGPUUnifyDivergentExitNodes does not update the phi nodes in
the successors of blocks that is splits. This is fixed by calling
BasicBlock::splitBasicBlock to split the block instead of doing it
manually. This does extra work because a new conditional branch is
created in BB which is immediately replaced, but I think the simplicity
is worth it. It also helps make the code more future proof in case other
things need to be updated.
llvm-svn: 364342
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
Summary:
This is patch 1 of the new DivergenceAnalysis (https://reviews.llvm.org/D50433).
The purpose of this patch is to free up the name DivergenceAnalysis for the new generic
implementation. The generic implementation class will be shared by specialized
divergence analysis classes.
Patch by: Simon Moll
Reviewed By: nhaehnle
Subscribers: jvesely, jholewinski, arsenm, nhaehnle, mgorny, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D50434
Change-Id: Ie8146b11be2c50d5312f30e11c7a3036a15b48cb
llvm-svn: 341071
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)
llvm-svn: 333954
Summary:
The current StructurizeCFG pass only works for CFG with one exit. AMDGPUUnifyDivergentExitNodes combines multiple "return" blocks and/or "unreachable" blocks
to one exit block for the Structurizer to work. However, infinite loop is another kind of special "exit", and if we don't handle it, the case of multiple exits will prevent the structurizer from working.
In this work, for each infinite loop, we add a dummy edge to the "return" block, and thus the AMDGPUUnifyDivergentExitNodes pass will work with infinite loops.
This will make CFG with infinite loops be structurized.
Reviewer:
nhaehnle
Differential Revision:
https://reviews.llvm.org/D46340
llvm-svn: 332625
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
This is a follow-up to https://reviews.llvm.org/D38138.
I fixed the capitalization of some functions because we're changing those
lines anyway and that helped verify that we weren't accidentally dropping
any options by using default param values.
llvm-svn: 314930
This was intended to be no-functional-change, but it's not - there's a test diff.
So I thought I should stop here and post it as-is to see if this looks like what was expected
based on the discussion in PR34603:
https://bugs.llvm.org/show_bug.cgi?id=34603
Notes:
1. The test improvement occurs because the existing 'LateSimplifyCFG' marker is not carried
through the recursive calls to 'SimplifyCFG()->SimplifyCFGOpt().run()->SimplifyCFG()'.
The parameter isn't passed down, so we pick up the default value from the function signature
after the first level. I assumed that was a bug, so I've passed 'Options' down in all of the
'SimplifyCFG' calls.
2. I split 'LateSimplifyCFG' into 2 bits: ConvertSwitchToLookupTable and KeepCanonicalLoops.
This would theoretically allow us to differentiate the transforms controlled by those params
independently.
3. We could stash the optional AssumptionCache pointer and 'LoopHeaders' pointer in the struct too.
I just stopped here to minimize the diffs.
4. Similarly, I stopped short of messing with the pass manager layer. I have another question that
could wait for the follow-up: why is the new pass manager creating the pass with LateSimplifyCFG
set to true no matter where in the pipeline it's creating SimplifyCFG passes?
// Create an early function pass manager to cleanup the output of the
// frontend.
EarlyFPM.addPass(SimplifyCFGPass());
-->
/// \brief Construct a pass with the default thresholds
/// and switch optimizations.
SimplifyCFGPass::SimplifyCFGPass()
: BonusInstThreshold(UserBonusInstThreshold),
LateSimplifyCFG(true) {} <-- switches get converted to lookup tables and loops may not be in canonical form
If this is unintended, then it's possible that the current behavior of dropping the 'LateSimplifyCFG'
setting via recursion was masking this bug.
Differential Revision: https://reviews.llvm.org/D38138
llvm-svn: 314308
StructurizeCFG can't handle cases with multiple
returns creating regions with multiple exits.
Create a copy of UnifyFunctionExitNodes that only
unifies exit nodes that skips exit nodes
with uniform branch sources.
llvm-svn: 298729
