Summary:
Remove all the caching the clobber walker does, and that the
caching walker does. With the patch to enable storing clobbering
access results for stores, i can find no improvement with the cache
turned on (and a number of degradations, both time and memory, from
the cost of caching. For a large program i have, we do millions of
lookups and inserts with zero hits).
I haven't tried to rename or simplify the walker otherwise yet.
(Appreciate some perf testing on this past my own testing)
Reviewers: george.burgess.iv, davide
Subscribers: Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D31576
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299578 91177308-0d34-0410-b5e6-96231b3b80d8
stores with some fixes.
Summary:
This enables us to cache the clobbering access for stores, despite the
fact that we can't rewrite the use-def chains themselves.
Early testing shows that, after this change, for larger testcases, it
will be a significant net positive (memory and time) to remove the
walker caching.
Reviewers: george.burgess.iv, davide
Subscribers: Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D31567
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299486 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This enables us to cache the clobbering access for stores, despite the
fact that we can't rewrite the use-def chains themselves.
Early testing shows that, after this change, for larger testcases, it will be a significant net positive (memory and time) to remove the walker caching.
Reviewers: george.burgess.iv, davide
Subscribers: Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D31567
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299322 91177308-0d34-0410-b5e6-96231b3b80d8
Add updater to passes that now need it.
Move around code in MemorySSA to expose needed functions.
Summary: Mostly cleanup
Reviewers: george.burgess.iv
Subscribers: llvm-commits, Prazek
Differential Revision: https://reviews.llvm.org/D30221
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295887 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This lets one add aliasing stores to the updater.
(i'm next going to move the creation/etc functions to the updater)
Reviewers: george.burgess.iv
Subscribers: llvm-commits, Prazek
Differential Revision: https://reviews.llvm.org/D30154
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@295677 91177308-0d34-0410-b5e6-96231b3b80d8
We had various variants of defining dump() functions in LLVM. Normalize
them (this should just consistently implement the things discussed in
http://lists.llvm.org/pipermail/cfe-dev/2014-January/034323.html
For reference:
- Public headers should just declare the dump() method but not use
LLVM_DUMP_METHOD or #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
- The definition of a dump method should look like this:
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
LLVM_DUMP_METHOD void MyClass::dump() {
// print stuff to dbgs()...
}
#endif
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293359 91177308-0d34-0410-b5e6-96231b3b80d8
insertUse, moveBefore and moveAfter operations.
Summary:
This creates a basic MemorySSA updater that handles arbitrary
insertion of uses and defs into MemorySSA, as well as arbitrary
movement around the CFG. It replaces the current splice API.
It can be made to handle arbitrary control flow changes.
Currently, it uses the same updater algorithm from D28934.
The main difference is because MemorySSA is single variable, we have
the complete def and use list, and don't need anyone to give it to us
as part of the API. We also have to rename stores below us in some
cases.
If we go that direction in that patch, i will merge all the updater
implementations (using an updater_traits or something to provide the
get* functions we use, called read*/write* in that patch).
Sadly, the current SSAUpdater algorithm is way too slow to use for
what we are doing here.
I have updated the tests we have to basically build memoryssa
incrementally using the updater api, and make sure it still comes out
the same.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29047
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293356 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This is the first in a series of patches to add a simple, generalized updater to MemorySSA.
For MemorySSA, every def is may-def, instead of the normal must-def.
(the best way to think of memoryssa is "everything is really one variable, with different versions of that variable at different points in the program).
This means when updating, we end up having to do a bunch of work to touch defs below and above us.
In order to support this quickly, i have ilist'd all the defs for each block. ilist supports tags, so this is quite easy. the only slightly messy part is that you can't have two iplists for the same type that differ only whether they have the ownership part enabled or not, because the traits are for the value type.
The verifiers have been updated to test that the def order is correct.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29046
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293085 91177308-0d34-0410-b5e6-96231b3b80d8
analyses to have a common type which is enforced rather than using
a char object and a `void *` type when used as an identifier.
This has a number of advantages. First, it at least helps some of the
confusion raised in Justin Lebar's code review of why `void *` was being
used everywhere by having a stronger type that connects to documentation
about this.
However, perhaps more importantly, it addresses a serious issue where
the alignment of these pointer-like identifiers was unknown. This made
it hard to use them in pointer-like data structures. We were already
dodging this in dangerous ways to create the "all analyses" entry. In
a subsequent patch I attempted to use these with TinyPtrVector and
things fell apart in a very bad way.
And it isn't just a compile time or type system issue. Worse than that,
the actual alignment of these pointer-like opaque identifiers wasn't
guaranteed to be a useful alignment as they were just characters.
This change introduces a type to use as the "key" object whose address
forms the opaque identifier. This both forces the objects to have proper
alignment, and provides type checking that we get it right everywhere.
It also makes the types somewhat less mysterious than `void *`.
We could go one step further and introduce a truly opaque pointer-like
type to return from the `ID()` static function rather than returning
`AnalysisKey *`, but that didn't seem to be a clear win so this is just
the initial change to get to a reliably typed and aligned object serving
is a key for all the analyses.
Thanks to Richard Smith and Justin Lebar for helping pick plausible
names and avoid making this refactoring many times. =] And thanks to
Sean for the super fast review!
While here, I've tried to move away from the "PassID" nomenclature
entirely as it wasn't really helping and is overloaded with old pass
manager constructs. Now we have IDs for analyses, and key objects whose
address can be used as IDs. Where possible and clear I've shortened this
to just "ID". In a few places I kept "AnalysisID" to make it clear what
was being identified.
Differential Revision: https://reviews.llvm.org/D27031
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287783 91177308-0d34-0410-b5e6-96231b3b80d8
This patch fixes the non-determinism caused due to iterating SmallPtrSet's
which was uncovered due to the experimental "reverse iteration order " patch:
https://reviews.llvm.org/D26718
The following unit tests failed because of the undefined order of iteration.
LLVM :: Transforms/Util/MemorySSA/cyclicphi.ll
LLVM :: Transforms/Util/MemorySSA/many-dom-backedge.ll
LLVM :: Transforms/Util/MemorySSA/many-doms.ll
LLVM :: Transforms/Util/MemorySSA/phi-translation.ll
Reviewers: dberlin, mgrang
Subscribers: dberlin, llvm-commits, david2050
Differential Revision: https://reviews.llvm.org/D26704
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287563 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This allows us to mark when uses have been optimized.
This lets us avoid rewalking (IE when people call getClobberingAccess on everything), and also
enables us to later relax the requirement of use optimization during updates with less cost.
Reviewers: george.burgess.iv
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25172
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284771 91177308-0d34-0410-b5e6-96231b3b80d8
As Danny pointed out, defClobbersUseOrDef should use MemoryLocOrCall to make
sure fences are properly handled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284099 91177308-0d34-0410-b5e6-96231b3b80d8
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
