This adjusts the description of `llvm.memcpy` to also allow operands
to be equal. This is in line with what Clang currently expects.
This change is intended to be temporary and followed by re-introduce
a variant with the non-overlapping guarantee for cases where we can
actually ensure that property in the front-end.
See the links below for more details:
http://lists.llvm.org/pipermail/cfe-dev/2020-August/066614.html
and PR11763.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D86815
As discussed in D86843, -earlycse-debug-hash should be used in more regression
tests to catch inconsistency between the hashing and the equivalence check.
Differential Revision: https://reviews.llvm.org/D86863
MemoryPhis with a single value are correct, but can lead to errors when
updating. Clean up single entry Phis newly added when cloning blocks.
Resolves PR46574.
As mentioned in
http://lists.llvm.org/pipermail/llvm-dev/2020-July/143395.html,
loop-unswitch has not been ported to the NPM. Instead people are using
simple-loop-unswitch.
Pin all tests in Transforms/LoopUnswitch to legacy PM and replace all
other uses of loop-unswitch with simple-loop-unswitch.
One test that didn't fit into the above was
2014-06-21-congruent-constant.ll which seems to only pass with
loop-unswitch. That is also pinned to legacy PM.
Now all tests containing "-loop-unswitch" anywhere in the test succeed with
NPM turned on by default.
Reviewed By: ychen
Differential Revision: https://reviews.llvm.org/D85360
-print-memoryssa in legacy PM is print<memoryssa> in NPM.
Pin tests with -print-memoryssa to legacy PM.
Add corresponding tests for NPM where missing.
This fixes "unknown pass name 'print-memoryssa'".
Some tests still fail in Analysis/MemorySSA due to other passes that
haven't been ported.
pr43427.ll and pr43438.ll required adding -aa-pipeline=basic-aa,
-loop-simplify (since it doesn't run on legacy PM by default), and
decrementing some of the MemoryPhi numbers.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D85333
Merging alias results from different paths, when a path did phi
translation is not necesarily correct. Conservatively terminate such paths.
Aimed to fix PR46156.
Differential Revision: https://reviews.llvm.org/D84905
To match NewPM pass name, and also for readability.
Also rename rpo-functionattrs -> rpo-function-attrs while we're here.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D84694
This is D77454, except for stores. All the infrastructure work was done
for loads, so the remaining changes necessary are relatively small.
Differential Revision: https://reviews.llvm.org/D79968
The "null-pointer-is-valid" attribute needs to be checked by many
pointer-related combines. To make the check more efficient, convert
it from a string into an enum attribute.
In the future, this attribute may be replaced with data layout
properties.
Differential Revision: https://reviews.llvm.org/D78862
For IR generated by a compiler, this is really simple: you just take the
datalayout from the beginning of the file, and apply it to all the IR
later in the file. For optimization testcases that don't care about the
datalayout, this is also really simple: we just use the default
datalayout.
The complexity here comes from the fact that some LLVM tools allow
overriding the datalayout: some tools have an explicit flag for this,
some tools will infer a datalayout based on the code generation target.
Supporting this properly required plumbing through a bunch of new
machinery: we want to allow overriding the datalayout after the
datalayout is parsed from the file, but before we use any information
from it. Therefore, IR/bitcode parsing now has a callback to allow tools
to compute the datalayout at the appropriate time.
Not sure if I covered all the LLVM tools that want to use the callback.
(clang? lli? Misc IR manipulation tools like llvm-link?). But this is at
least enough for all the LLVM regression tests, and IR without a
datalayout is not something frontends should generate.
This change had some sort of weird effects for certain CodeGen
regression tests: if the datalayout is overridden with a datalayout with
a different program or stack address space, we now parse IR based on the
overridden datalayout, instead of the one written in the file (or the
default one, if none is specified). This broke a few AVR tests, and one
AMDGPU test.
Outside the CodeGen tests I mentioned, the test changes are all just
fixing CHECK lines and moving around datalayout lines in weird places.
Differential Revision: https://reviews.llvm.org/D78403
Summary: When phi translation cannot be performed, be conservative and make the MemoryLocation unknown.
Reviewers: george.burgess.iv
Subscribers: Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79386
Summary:
A valid DominatorTree is needed to do PhiTranslation.
Before this patch, a MemoryUse could be optimized to an access outside a loop, while the address it loads from is modified in the loop.
This can lead to a miscompile.
Reviewers: george.burgess.iv
Subscribers: Prazek, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D79068
This is fixing up various places that use the implicit
TypeSize->uint64_t conversion.
The new overloads in MemoryLocation.h are already used in various places
that construct a MemoryLocation from a TypeSize, including MemorySSA.
(They were using the implicit conversion before.)
Differential Revision: https://reviews.llvm.org/D76249
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.
When simplifying a Phi to the unique value found incoming, check that
there wasn't a Phi already created to break a cycle. If so, remove it.
Resolves PR43541.
Some additional nits included.
llvm-svn: 374471
Summary:
Whenever we get the previous definition, the assumption is that the
recursion starts ina reachable block.
If the recursion starts in an unreachable block, we may recurse
indefinitely. Handle this case by returning LoE if the block is
unreachable.
Resolves PR43426.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68809
llvm-svn: 374447
Summary:
The rule for the moveAllAfterMergeBlocks API si for all instructions
from `From` to have been moved to `To`, while keeping the CFG edges (and
block terminators) unchanged.
Update all the callsites for moveAllAfterMergeBlocks to follow this.
Pending follow-up: since the same behavior is needed everytime, merge
all callsites into one. The common denominator may be the call to
`MergeBlockIntoPredecessor`.
Resolves PR43569.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68659
llvm-svn: 374177
MemoryPhis should be added in the IDF of the blocks newly gaining Defs.
This includes the blocks that gained a Phi and the block gaining a Def,
if the block did not have one before.
Resolves PR43427.
llvm-svn: 373505
If a single predecessor is found, still check if the block is
unreachable. The test that found this had a self loop unreachable block.
Resolves PR43493.
llvm-svn: 373383
The check for "was there an access in this block" should be: is the last
access in this block and is it not a newly inserted phi.
Resolves new test in PR43438.
Also fix a typo when simplifying trivial Phis to match the comment.
llvm-svn: 373380
Summary:
If a block has all incoming values with the same MemoryAccess (ignoring
incoming values from unreachable blocks), then use that incoming
MemoryAccess and do not create a Phi in the first place.
Revert IDF work-around added in rL372673; it should not be required unless
the Def inserted is the first in its block.
The patch also cleans up a series of tests, added during the many
iterations on insertDef.
The patch also fixes PR43438.
The same issue that occurs in insertDef with "adding phis, hence the IDF of
Phis is needed", can also occur in fixupDefs: the `getPreviousRecursive`
call only adds Phis walking on the predecessor edges, which means there
may be the case of a Phi added walking the CFG "backwards" which
triggers the needs for an additional Phi in successor blocks.
Such Phis are added during fixupDefs only in the presence of unreachable
blocks.
Hence this highlights the need to avoid adding Phis in blocks with
unreachable predecessors in the first place.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67995
llvm-svn: 372932
Summary:
MemoryPhis may be needed following a Def insertion inthe IDF of all the
new accesses added (phis + potentially a def). Ensure this also occurs when
only the new MemoryPhis are the defining accesses.
Note: The need for computing IDF here is because of new Phis added with
edges incoming from unreachable code, Phis that had previously been
simplified. The preferred solution is to not reintroduce such Phis.
This patch is the needed fix while working on the preferred solution.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67927
llvm-svn: 372673
Summary:
When inserting a Def, the current algorithm is walking edges backward
and inserting new Phis where needed. There may be additional Phis needed
in the IDF of the newly inserted Def and Phis.
Adding Phis in the IDF of the Def was added ina previous patch, but we
may also need other Phis in the IDF of the newly added Phis.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67637
llvm-svn: 372138
Summary:
Regularly when moving an instruction that may not read or write memory,
the instruction is not modelled in MSSA, so not action is necessary.
For a non-conventional AA pipeline, MSSA needs to explicitly check when
creating accesses, so as to not model instructions that may not read and
write memory.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67562
llvm-svn: 372137
Summary:
Do not model debuginfo intrinsics in MemorySSA.
Regularly these are non-memory modifying instructions. With -disable-basicaa, they were being modelled as Defs.
Reviewers: george.burgess.iv
Subscribers: aprantl, Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67307
llvm-svn: 371565
Summary:
When inserting a new Def, and inserting Phis in the IDF when needed,
also mark the already existing Phis in the IDF as non-optimized, since
these may need fixing as well.
In the test attached, there is a Phi in the IDF that happens to be
trivial, and is wrongfully removed by the call to getLastDef that
follows. This is a valid situation and the existing IDF Phis need to
marked as "may need fixing" as well.
Resolves PR43044.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66495
llvm-svn: 369464
Summary:
When inserting uses from outside the MemorySSA creation, we don't
normally need to rename uses, based on the assumption that there will be
no inserted Phis (if Def existed that required a Phi, that Phi already
exists). However, when dealing with unreachable blocks, MemorySSA will
optimize away Phis whose incoming blocks are unreachable, and these Phis end
up being re-added when inserting a Use.
There are two potential solutions here:
1. Analyze the inserted Phis and clean them up if they are unneeded
(current method for cleaning up trivial phis does not cover this)
2. Leave the Phi in place and rename uses, the same way as whe inserting
defs.
This patch use approach 2.
Resolves first test in PR42940.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66033
llvm-svn: 369291
Summary:
Verify that the incoming defs into phis are the last defs from the
respective incoming blocks.
When moving blocks, insertDef must RenameUses. Adding this verification
makes GVNHoist tests fail that uncovered this issue.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63147
llvm-svn: 367451
Summary:
LoopRotate may simplify instructions, leading to the new instructions not having memory accesses created for them.
Allow this behavior, by allowing the new access to be null when the template is null, and looking upwards for the proper defined access when dealing with simplified instructions.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65338
llvm-svn: 367352
Summary:
The map kept in loop rotate is used for instruction remapping, in order
to simplify the clones of instructions. Thus, if an instruction can be
simplified, its simplified value is placed in the map, even when the
clone is added to the IR. MemorySSA in contrast needs to know about that
clone, so it can add an access for it.
To resolve this: keep a different map for MemorySSA.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63680
llvm-svn: 365672
Summary:
The getClobberingMemoryAccess API checks for clobbering accesses in a loop by walking the backedge. This may check if a memory access is being
clobbered by the loop in a previous iteration, depending how smart AA got over the course of the updates in MemorySSA (it does not occur when built from scratch).
If no clobbering access is found inside the loop, it will optimize to an access outside the loop. This however does not mean that access is safe to sink.
Given:
```
for i
load a[i]
store a[i]
```
The access corresponding to the load can be optimized to outside the loop, and the load can be hoisted. But it is incorrect to sink it.
In order to sink the load, we'd need to check no Def clobbers the Use in the same iteration. With this patch we currently restrict sinking to either
Defs not existing in the loop, or Defs preceding the load in the same block. An easy extension is to ensure the load (Use) post-dominates all Defs.
Caught by PR42294.
This issue also shed light on the converse problem: hoisting stores in this same scenario would be illegal. With this patch we restrict
hoisting of stores to the case when their corresponding Defs are dominating all Uses in the loop.
Reviewers: george.burgess.iv
Subscribers: jlebar, Prazek, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63582
llvm-svn: 363982
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
llvm-svn: 363880
Florian Hahn