This CL didn't actually address the test case in PR30499, and clang
still crashes.
Also revert dependent change "Memory-SSA cleanup of clobbers interface, NFC"
Reverts r283965 and r283967.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284093 91177308-0d34-0410-b5e6-96231b3b80d8
This is a refreshed version of a patch that was reverted: it fixes
the problems reported in both PR30216 and PR30499, and
contains all the test-cases from both bugs.
To hoist stores past loads, we used to search for potential
conflicting loads on the hoisting path by following a MemorySSA
def-def link from the store to be hoisted to the previous
defining memory access, and from there we followed the def-use
chains to all the uses that occur on the hoisting path. The
problem is that the def-def link may point to a store that does
not alias with the store to be hoisted, and so the loads that are
walked may not alias with the store to be hoisted, and even as in
the testcase of PR30216, the loads that may alias with the store
to be hoisted are not visited.
The current patch visits all loads on the path from the store to
be hoisted to the hoisting position and uses the alias analysis
to ask whether the store may alias the load. I was not able to
use the MemorySSA functionality to ask for whether load and
store are clobbered: I'm not sure which function to call, so I
used a call to AA->isNoAlias().
Store past store is still working as before using a MemorySSA
query: I added an extra test to pr30216.ll to make sure store
past store does not regress.
Tested on x86_64-linux with check and a test-suite run.
Differential Revision: https://reviews.llvm.org/D25476
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283965 91177308-0d34-0410-b5e6-96231b3b80d8
Given that we're not currently using blocker info, and whether or not we
will end up using it it is unclear, don't waste 8 (or 4) bytes of memory
per path node.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279493 91177308-0d34-0410-b5e6-96231b3b80d8
If the result of the find is only used to compare against end(), just
use is_contained instead.
No functionality change is intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278469 91177308-0d34-0410-b5e6-96231b3b80d8
Besides a general consistently benefit, the extra layer of indirection
allows the mechanical part of https://reviews.llvm.org/D23256 that
requires touching every transformation and analysis to be factored out
cleanly.
Thanks to David for the suggestion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278077 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Ensure that the MemorySSA object never changes address when using the
new pass manager since the walkers contained by MemorySSA cache pointers
to it at construction time. This is achieved by wrapping the
MemorySSAAnalysis result in a unique_ptr. Also add some asserts that
check for this bug.
Reviewers: george.burgess.iv, dberlin
Subscribers: mcrosier, hfinkel, chandlerc, silvas, llvm-commits
Differential Revision: https://reviews.llvm.org/D23171
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278028 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In the use optimizer, we need to keep of whether the lower bound still
dominates us or else we may decide a lower bound is still valid when it
is not due to intervening pushes/pops. Fixes PR28880 (and probably a
bunch of other things).
Reviewers: george.burgess.iv
Subscribers: MatzeB, llvm-commits, sebpop
Differential Revision: https://reviews.llvm.org/D23237
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277978 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Originally the plan was to use the custom worklist to do some block popping,
and because we don't actually need a visited set. The custom one we have
here is slightly broken, and it's not worth fixing vs using depth_first_iterator since we aren't going to go the route we originally
were.
Fixes PR28874
Reviewers: george.burgess.iv
Subscribers: llvm-commits, gberry
Differential Revision: https://reviews.llvm.org/D23187
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277880 91177308-0d34-0410-b5e6-96231b3b80d8
Not a correctness issue, but it would be nice if we didn't have to
recompute our block numbering (worst-case) every time we move MSSA.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277652 91177308-0d34-0410-b5e6-96231b3b80d8
Didn't want to fold this in with r277640, since it touches bits that
aren't entirely related to r277640.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277641 91177308-0d34-0410-b5e6-96231b3b80d8
This is a follow-up to r277637. It teaches MemorySSA that invariant
loads (and loads of provably constant memory) are always liveOnEntry.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277640 91177308-0d34-0410-b5e6-96231b3b80d8
This patch makes MemorySSA recognize atomic/volatile loads, and makes
MSSA treat said loads specially. This allows us to be a bit more
aggressive in some cases.
Administrative note: Revision was LGTM'ed by reames in person.
Additionally, this doesn't include the `invariant.load` recognition in
the differential revision, because I feel it's better to commit that
separately. Will commit soon.
Differential Revision: https://reviews.llvm.org/D16875
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277637 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a bug where we'd sometimes cache overly-conservative results
with our walker. This bug was made more obvious by r277480, which makes
our cache far more spotty than it was. Test case is llvm-unit, because
we're likely going to use CachingWalker only for def optimization in the
future.
The bug stems from that there was a place where the walker assumed that
`DefNode.Last` was a valid target to cache to when failing to optimize
phis. This is sometimes incorrect if we have a cache hit. The fix is to
use the thing we *can* assume is a valid target to cache to. :)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277559 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: We really want to move towards MemoryLocOrCall (or fix AA) everywhere, but for now, this lets us have a single instructionClobbersQuery.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23072
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277530 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes PR28670
Summary:
Rewrite the use optimizer to be less memory intensive and 50% faster.
Fixes PR28670
The new use optimizer works like a standard SSA renaming pass, storing
all possible versions a MemorySSA use could get in a stack, and just
tracking indexes into the stack.
This uses much less memory than caching N^2 alias query results.
It's also a lot faster.
The current version defers phi node walking to the normal walker.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23032
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277480 91177308-0d34-0410-b5e6-96231b3b80d8
checkClobberSanity will now be run for all results of `ClobberWalk`,
instead of just the crazy phi-optimized ones. This can help us catch
cases where our cache is being wonky.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276553 91177308-0d34-0410-b5e6-96231b3b80d8
liveOnEntry is always a MemoryDef; asserting that a MemoryPhi isn't
liveOnEntry, while correct, isn't very helpful. :)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276542 91177308-0d34-0410-b5e6-96231b3b80d8
A seemingly common use for the walker's getClobberingMemoryAccess
function is:
```
MemoryAccess *getClobber(MemorySSAWalker *W, MemoryUseOrDef *MUD) {
const Instruction *I = MUD->getMemoryInst();
return W->getClobberingMemoryAccess(I);
}
```
Which is kind of redundant, since walkers will ultimately query MSSA to
find out which MemoryAccess `I` maps to (...which is always `MUD`).
So, this patch adds an overload of getClobberingMemoryAccess that
accepts MemoryAccesses directly. As a result, the Instruction overload
of getClobberingMemoryAccess becomes a lightweight wrapper around our
new overload.
Additionally, this patch un`virtual`izes the Instruction overload of
getClobberingMemoryAccess, since there doesn't seem to be a walker that
benefits from that being virtual, and I can't think of how else one
would implement it. Happy to make it virtual again if we would benefit
from doing so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276169 91177308-0d34-0410-b5e6-96231b3b80d8
This patch updates MemorySSA's use-optimizing walker to be more
accurate and, in some cases, faster.
Essentially, this changed our core walking algorithm from a
cache-as-you-go DFS to an iteratively expanded DFS, with all of the
caching happening at the end. Said expansion happens when we hit a Phi,
P; we'll try to do the smallest amount of work possible to see if
optimizing above that Phi is legal in the first place. If so, we'll
expand the search to see if we can optimize to the next phi, etc.
An iteratively expanded DFS lets us potentially quit earlier (because we
don't assume that we can optimize above all phis) than our old walker.
Additionally, because we don't cache as we go, we can now optimize above
loops.
As an added bonus, this patch adds a ton of verification (if
EXPENSIVE_CHECKS are enabled), so finding bugs is easier.
Differential Revision: https://reviews.llvm.org/D21777
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275940 91177308-0d34-0410-b5e6-96231b3b80d8
Calling getModRefInfo with a fence resulted in crashes because fences
don't have a memory location. Add a new predicate to Instruction
called isFenceLike which indicates that the instruction mutates memory
but not any single memory location in particular. In practice, it is a
proxy for the set of instructions which "mayWriteToMemory" but cannot be
used with MemoryLocation::get.
This fixes PR28570.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275581 91177308-0d34-0410-b5e6-96231b3b80d8
This patch moves MSSA's caching walker into MemorySSA, and moves the
actual definition of MSSA's caching walker out of MemorySSA.h. This is
done in preparation for the new walker, which should be out for review
soonish.
Also, this patch removes a field from UpwardsMemoryQuery and has a few
lines of diff from clang-format'ing MemorySSA.cpp.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273723 91177308-0d34-0410-b5e6-96231b3b80d8
Add support for the new pass manager to MemorySSA pass.
Change MemorySSA to be computed eagerly upon construction.
Change MemorySSAWalker to be owned by the MemorySSA object that creates
it.
Reviewers: dberlin, george.burgess.iv
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19664
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271432 91177308-0d34-0410-b5e6-96231b3b80d8
It turns out that too many passes are relying on alias analysis results
for control dependencies. Until we fix that by introducing a more accurate
modelling of control dependencies, special case assume in MemorySSA instead.
Also introduce tests to ensure we don't regress the FunctionAttrs or LICM
passes.
Differential Revision: http://reviews.llvm.org/D20658
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270823 91177308-0d34-0410-b5e6-96231b3b80d8
There is only one caller of MemorySSA::createNewAccess, and it passes true
as the IgnoreNonMemory argument. Remove that argument and fold its behavior
into createNewAccess.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@270812 91177308-0d34-0410-b5e6-96231b3b80d8
This patch fixes two somewhat related bugs in MemorySSA's caching
walker. These bugs were found because D19695 brought up the problem
that we'd have defs cached to themselves, which is incorrect.
The bugs this fixes are:
- We would sometimes skip the nearest clobber of a MemoryAccess, because
we would query our cache for a given potential clobber before
checking if the potential clobber is the clobber we're looking for.
The cache entry for the potential clobber would point to the nearest
clobber *of the potential clobber*, so if that was a cache hit, we'd
ignore the potential clobber entirely.
- There are times (sometimes in DFS, sometimes in the getClobbering...
functions) where we would insert cache entries that say a def
clobbers itself.
There's a bit of common code between the fixes for the bugs, so they
aren't split out into multiple commits.
This patch also adds a few unit tests, and refactors existing tests a
bit to reduce the duplication of setup code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268087 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Historically, we had a switch in the Makefiles for turning on "expensive
checks". This has never been ported to the cmake build, but the
(dead-ish) code is still around.
This will also make it easier to turn it on in buildbots.
Reviewers: chandlerc
Subscribers: jyknight, mzolotukhin, RKSimon, gberry, llvm-commits
Differential Revision: http://reviews.llvm.org/D19723
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268050 91177308-0d34-0410-b5e6-96231b3b80d8
