Adds new tests for add and sub instructions before reaching a select.
Also adds tests using different bit widths for memory, including
non-power-of-two integers.
This builds on the previous forked pointers patch, which only accepted
a single select as the pointer to check. A recursive function to walk
through IR has been added, which searches for either a loop-invariant
or addrec SCEV.
This will only handle a single fork at present, so selects of selects
or a GEP with a select for both the base and offset will be rejected.
There is also a recursion limit with a cli option to change it.
Reviewed By: fhahn, david-arm
Differential Revision: https://reviews.llvm.org/D108699
* Converted tests to use opaque pointers
* Added suggested test for inbounds GEP
* Added a test for forks on both the base and offset terms of a GEP
* Added a test for a select of a select
* Added a test for a GEP with >2 operands
* Added a test for vector GEPs
This reverts commit 7aa8a67882.
This version includes fixes to address issues uncovered after
the commit landed and discussed at D11448.
Those include:
* Limit select-traversal to selects inside the loop.
* Freeze pointers resulting from looking through selects to avoid
branch-on-poison.
Scaffolding support for generating runtime checks for multiple SCEV expressions
per pointer. The initial version just adds support for looking through
a single pointer select.
The more sophisticated logic for analyzing forks is in D108699
Reviewed By: huntergr
Differential Revision: https://reviews.llvm.org/D114487
Previously we relied on the pointee type to determine what type we need
to do runtime pointer access checks.
With opaque pointers, we can access a pointer with more than one type,
so now we keep track of all the types we're accessing a pointer's
memory with.
Also some other minor getPointerElementType() removals.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D119047
Adds new optimization remarks when vectorization fails.
More specifically, new remarks are added for following 4 cases:
- Backward dependency
- Backward dependency that prevents Store-to-load forwarding
- Forward dependency that prevents Store-to-load forwarding
- Unknown dependency
It is important to note that only one of the sources
of failures (to vectorize) is reported by the remarks.
This source of failure may not be first in program order.
A regression test has been added to test the following cases:
a) Loop can be vectorized: No optimization remark is emitted
b) Loop can not be vectorized: In this case an optimization
remark will be emitted for one source of failure.
Reviewed By: sdesmalen, david-arm
Differential Revision: https://reviews.llvm.org/D108371
This reverts commit 640beb38e7.
That commit caused performance degradtion in Quicksilver test QS:sGPU and a functional test failure in (rocPRIM rocprim.device_segmented_radix_sort).
Reverting until we have a better solution to s_cselect_b64 codegen cleanup
Change-Id: Ibf8e397df94001f248fba609f072088a46abae08
Reviewed By: kzhuravl
Differential Revision: https://reviews.llvm.org/D115960
Change-Id: Id169459ce4dfffa857d5645a0af50b0063ce1105
0a00d64 turned an early exit here into an assertion, but the assertion
can be triggered, as PR52920 shows.
The later code is agnostic to the accessed type, so just drop the
assert. The patch also adds tests for LAA directly and
loop-load-elimination to show the behavior is sane.
In the isDependence function the code does not try hard enough
to determine the dependence between types. If the types are
different it simply gives up, whereas in fact what we really
care about are the type sizes. I've changed the code to compare
sizes instead of types.
Reviewed By: fhahn, sdesmalen
Differential Revision: https://reviews.llvm.org/D108763
The supplied test case, reduced from real world code, crashes with a
'Invalid size request on a scalable vector.' error.
Since it's similar in spirit to an existing LAA test, rename the file to
generalize it to both.
Differential Revision: https://reviews.llvm.org/D114155
When checking to see if we can apply IR flags to a SCEV, we need to identify a bound on the defining scope of the SCEV to be produced. We'd previously added support for a couple SCEVExpr types which trivially imply bounds, but hadn't handled types such as umax where the bounds come from the bounds of the operands. This does the obvious thing, and recurses through operands searching for a tighter bound on the defining scope.
I'm honestly surprised by how little this seems to mater on existing tests, but it's worth doing for completeness sake alone.
Differential Revision: https://reviews.llvm.org/D111191
This fixes a violation of the wrap flag rules introduced in c4048d8f. This was also noted in the (very old) PR23527.
The issue being fixed is that we assume the inbound flag on any GEP assumes that all users of *any* gep (or add) which happens to map to that SCEV would also be UB if the (other) gep overflowed. That's simply not true.
In terms of the test diffs, I don't see anything seriously problematic. The lost flags are expected (given the semantic restriction on when its legal to tag the SCEV), and there are several cases where the previously inferred flags are unsound per the new semantics.
The only common trend I noticed when looking at the deltas is that by not considering branch on poison as immediate UB in ValueTracking, we do miss a few cases we could reclaim. We may be able to claw some of these back with the follow ideas mentioned in PR51817.
It's worth noting that most of the changes are analysis result only changes. The two transform changes are pretty minimal. In one case, we miss the opportunity to infer a nuw (correctly). In the other, we fail to fold an exit and produce a loop invariant form instead. This one is probably over-reduced as the program appears to be undefined in practice, and neither before or after exploits that.
Differential Revision: https://reviews.llvm.org/D109789
SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses for each incoming pointer
value.
This results in 2 more loops vectorized in SPEC2000/186.crafty and
avoids regressions when sinking instructions before vectorizing.
Fixes PR50296, PR50288.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D102266
Only tests in llvm/test/Analysis.
-analyze is legacy PM-specific.
This only touches files with `-passes`.
I looked through everything and made sure that everything had a new PM equivalent.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D109040
This is a followup to D104662 to generate slightly nicer code for
pointer overflow checks. Bypass expandAddToGEP and instead
explicitly generate i8 GEPs. This saves some bitcasts and negates
the value in a more obvious way. In particular, this prevents SCEV
from looking through the umul.with.overflow, same as in the integer
case.
The wrapping-pointer-ni.ll test deserves a comment: Previously,
this generated a typed GEP which used the umulo argument rather
than the multiplication result. This results in more compact IR in
that case, but effectively does the multiplication twice, the
second one is just hidden in the GEP. Reusing the umulo result
seems pretty reasonable to me.
Differential Revision: https://reviews.llvm.org/D109093
Currently we drop wrapping flags for expressions like (A + C1)<flags> - C2.
But we can retain flags under certain conditions:
* Adding a smaller constant is NUW if the original AddExpr was NUW.
* Adding a constant with the same sign and small magnitude is NSW, if the
original AddExpr was NSW.
This can improve results after using `SimplifyICmpOperands`, which may
subtract one in order to use stricter predicates, as is the case for
`isKnownPredicate`.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D104319
This reverts commit 1ed7f8ede5.
This change can cause loop-distribute to crash in some cases. Revert
until I have more time to wrap up a fix.
See PR50296, PR5028 and D102266.
SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses for each incoming pointer
value.
This results in 2 more loops vectorized in SPEC2000/186.crafty and
avoids regressions when sinking instructions before vectorizing.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D101286
Currently, InsertNoopCastOfTo() would implicitly insert that cast,
but now that we have SCEVPtrToIntExpr, i'm hoping we could stop
InsertNoopCastOfTo() from doing that. But first all users must be fixed.
After D98856 these tests will by default break (fatal_error) if any of
the wrong interfaces are used, so there's no longer a need to have a
RUN line that checks for a warning message emitted by the compiler.
The TypeSize warning would occur because RuntimePointerChecking::insert
was not scalable vector aware. The fix is to use
ScalarEvolution::getSizeOfExpr to grab the size of types.
Differential Revision: https://reviews.llvm.org/D90171
The SCEV code for constructing GEP expressions currently assumes
that the addition of the base and all the offsets is nsw if the GEP
is inbounds. While the addition of the offsets is indeed nsw, the
addition to the base address is not, as the base address is
interpreted as an unsigned value.
Fix the GEP expression code to not assume nsw for the base+offset
calculation. However, do assume nuw if we know that the offset is
non-negative. With this, we use the same behavior as the
construction of GEP addrecs does. (Modulo the fact that we
disregard SCEV unification, as the pre-existing FIXME points out).
Differential Revision: https://reviews.llvm.org/D90648
We do not need to use the implicit cast here. We can instead can rely on
a comparison between two TypeSize objects instead. This algorithm will
work fine with scalable vectors.
Reviewed By: DavidTruby
Differential Revision: https://reviews.llvm.org/D90146
Same change as 0dda633317, but for
mul expressions. We want to first fold any constant operans and
then strengthen the nowrap flags, as we can compute more precise
flags at that point.
This reverts commit r365260 which broke the following tests:
Clang :: CodeGenCXX/cfi-mfcall.cpp
Clang :: CodeGenObjC/ubsan-nullability.m
LLVM :: Transforms/LoopVectorize/AArch64/pr36032.ll
llvm-svn: 365284
Without this, we have the unfortunate property that tests are dependent on the order of operads passed the CreateOr and CreateAnd functions. In actual usage, we'd promptly optimize them away, but it made tests slightly more verbose than they should have been.
llvm-svn: 365260
This case is slightly tricky, because loop distribution should be
allowed in some cases, and not others. As long as runtime dependency
checks don't need to be introduced, this should be OK. This is further
complicated by the fact that LoopDistribute partially ignores if LAA
says that vectorization is safe, and then does its own runtime pointer
legality checks.
Note this pass still does not handle noduplicate correctly, as this
should always be forbidden with it. I'm not going to bother trying to
fix it, as it would require more effort and I think noduplicate should
be removed.
https://reviews.llvm.org/D62607
llvm-svn: 363160
Summary:
Currently we express umin as `~umax(~x, ~y)`. However, this becomes
a problem for operands in non-integral pointer spaces, because `~x`
is not something we can compute for `x` non-integral. However, since
comparisons are generally still allowed, we are actually able to
express `umin(x, y)` directly as long as we don't try to express is
as a umax. Support this by adding an explicit umin/smin representation
to SCEV. We do this by factoring the existing getUMax/getSMax functions
into a new function that does all four. The previous two functions were
largely identical.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D50167
llvm-svn: 360159
Summary:
Currently, when vectorizing stores to uniform addresses, the only
instance we prevent vectorization is if there are multiple stores to the
same uniform address causing an unsafe dependency.
This patch teaches LAA to avoid vectorizing loops that have an unsafe
cross-iteration dependency between a load and a store to the same uniform address.
Fixes PR39653.
Reviewers: Ayal, efriedma
Subscribers: rkruppe, llvm-commits
Differential Revision: https://reviews.llvm.org/D54538
llvm-svn: 347220
Summary:
Teach vectorizer about vectorizing variant value stores to uniform
address. Similar to rL343028, we do not allow vectorization if we have
multiple stores to the same uniform address.
Cost model already has the change for considering the extract
instruction cost for a variant value store. See added test cases for how
vectorization is done.
The patch also contains changes to the ORE messages.
Reviewers: Ayal, mkuper, anemet, hsaito
Subscribers: rkruppe, llvm-commits
Differential Revision: https://reviews.llvm.org/D52656
llvm-svn: 344613
Summary:
We are overly conservative in loop vectorizer with respect to stores to loop
invariant addresses.
More details in https://bugs.llvm.org/show_bug.cgi?id=38546
This is the first part of the fix where we start with vectorizing loop invariant
values to loop invariant addresses.
This also includes changes to ORE for stores to invariant address.
Reviewers: anemet, Ayal, mkuper, mssimpso
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50665
llvm-svn: 343028
Graham Hunter