Clamp function was too optimistic when choosing signed or unsigned min/max function for calculations.
In fact, `!IsSignedPredicate` guarantees us that `Smallest` and `Greatest` can be compared safely using unsigned
predicates, but we did not check this for `S` which can in theory be negative.
This patch makes Clamp use signed min/max for cases when it fails to prove `S` being non-negative,
and it adds a test where such situation may lead to incorrect conditions calculation.
Differential Revision: https://reviews.llvm.org/D36873
llvm-svn: 311205
Summary:
Memcpy intrinsics have size argument of any integer type, like i32 or i64.
Fixed size type along with its value when cloning the intrinsic.
Reviewers: davidxl, xur
Reviewed By: davidxl
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D36844
llvm-svn: 311188
VPlan is an ongoing effort to refactor and extend the Loop Vectorizer. This
patch introduces the VPlan model into LV and uses it to represent the vectorized
code and drive the generation of vectorized IR.
In this patch VPlan models the vectorized loop body: the vectorized control-flow
is represented using VPlan's Hierarchical CFG, with predication refactored from
being a post-vectorization-step into a vectorization planning step modeling
if-then VPRegionBlocks, and generating code inline with non-predicated code. The
vectorized code within each VPBasicBlock is represented as a sequence of
Recipes, each responsible for modelling and generating a sequence of IR
instructions. To keep the size of this commit manageable the Recipes in this
patch are coarse-grained and capture large chunks of LV's code-generation logic.
The constructed VPlans are dumped in dot format under -debug.
This commit retains current vectorizer output, except for minor instruction
reorderings; see associated modifications to lit tests.
For further details on the VPlan model see docs/Proposals/VectorizationPlan.rst
and its references.
Authors: Gil Rapaport and Ayal Zaks
Differential Revision: https://reviews.llvm.org/D32871
llvm-svn: 311077
If we want to substitute the relocation of derived pointer with gep of base then
we must ensure that relocation of base dominates the relocation of derived pointer.
Currently only check for basic block is present. However it is possible that both
relocation are in the same basic block but relocation of derived pointer is defined
earlier.
The patch moves the relocation of base pointer right before relocation of derived
pointer in this case.
Reviewers: sanjoy,artagnon,igor-laevsky,reames
Reviewed By: reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D36462
llvm-svn: 311067
Summary:
This patch teaches ADCE to preserve both DominatorTrees and PostDominatorTrees.
I didn't notice any performance impact when bootstrapping clang with this patch.
The patch was originally committed in r311039 and reverted in r311049.
This revision fixes the problem with not adding a dependency on the
DominatorTreeWrapperPass for the LegacyPassManager.
Reviewers: dberlin, chandlerc, sanjoy, davide, grosser, brzycki
Reviewed By: davide
Subscribers: grandinj, zhendongsu, llvm-commits, david2050
Differential Revision: https://reviews.llvm.org/D35869
llvm-svn: 311057
Summary:
This patch teaches ADCE to preserve both DominatorTrees and PostDominatorTrees.
I didn't notice any performance impact when bootstrapping clang with this patch.
Reviewers: dberlin, chandlerc, sanjoy, davide, grosser, brzycki
Reviewed By: davide
Subscribers: grandinj, zhendongsu, llvm-commits, david2050
Differential Revision: https://reviews.llvm.org/D35869
llvm-svn: 311039
To clear assumptions that are potentially invalid after trivialization, we need
to walk the use/def chain. Normally, the only way to reach an instruction with
an unsized type is via an instruction that has side effects (or otherwise will
demand its input bits). That would stop the walk. However, if we have a
readnone function that returns an unsized type (e.g., void), we must avoid
asking for the demanded bits of the function call's return value. A
void-returning readnone function is always dead (and so we can stop walking the
use/def chain here), but the check is necessary to avoid asserting.
Fixes PR34211.
llvm-svn: 311014
- Set the default runtime unroll count to 4 and use the newly added
UnrollRemainder option.
- Create loop cost and force unroll for a cost less than 12.
- Disable unrolling on Thumb1 only targets.
Differential Revision: https://reviews.llvm.org/D36134
llvm-svn: 310997
Summary: When we move then-else code to if, we need to merge its debug info, otherwise the hoisted instruction may have inaccurate debug info attached.
Reviewers: aprantl, probinson, dblaikie, echristo, loladiro
Reviewed By: aprantl
Subscribers: sanjoy, llvm-commits
Differential Revision: https://reviews.llvm.org/D36778
llvm-svn: 310985
We were only allowing ConstantInt before. This patch allows splat of ConstantInt too.
Differential Revision: https://reviews.llvm.org/D36763
llvm-svn: 310970
The %T lit expansion expands to a common directory shared between all the tests in the same directory, which is unexpected and unintuitive, and more importantly, it's been a source of subtle race conditions and flaky tests. In https://reviews.llvm.org/D35396, it was agreed that it would be best to simply ban %T and only keep %t, which is unique to each test. When a test needs a temporary directory, it can just create one using mkdir %t.
This patch removes %T in llvm.
Differential Revision: https://reviews.llvm.org/D36495
llvm-svn: 310953
Narrow ops are better for bit-tracking, and in the case of vectors,
may enable better codegen.
As the trunc test shows, this can allow follow-on simplifications.
There's a block of code in visitTrunc that deals with shifted ops
with FIXME comments. It may be possible to remove some of that now,
but I want to make sure there are no problems with this step first.
http://rise4fun.com/Alive/Y3a
Name: hoist_ashr_ahead_of_sext_1
%s = sext i8 %x to i32
%r = ashr i32 %s, 3 ; shift value is < than source bit width
=>
%a = ashr i8 %x, 3
%r = sext i8 %a to i32
Name: hoist_ashr_ahead_of_sext_2
%s = sext i8 %x to i32
%r = ashr i32 %s, 8 ; shift value is >= than source bit width
=>
%a = ashr i8 %x, 7 ; so clamp this shift value
%r = sext i8 %a to i32
Name: junc_the_trunc
%a = sext i16 %v to i32
%s = ashr i32 %a, 18
%t = trunc i32 %s to i16
=>
%t = ashr i16 %v, 15
llvm-svn: 310942
Summary:
This patch teaches PostDominatorTree about infinite loops. It is built on top of D29705 by @dberlin which includes a very detailed motivation for this change.
What's new is that the patch also teaches the incremental updater how to deal with reverse-unreachable regions and how to properly maintain and verify tree roots. Before that, the incremental algorithm sometimes ended up preserving reverse-unreachable regions after updates that wouldn't appear in the tree if it was constructed from scratch on the same CFG.
This patch makes the following assumptions:
- A sequence of updates should produce the same tree as a recalculating it.
- Any sequence of the same updates should lead to the same tree.
- Siblings and roots are unordered.
The last two properties are essential to efficiently perform batch updates in the future.
When it comes to the first one, we can decide later that the consistency between freshly built tree and an updated one doesn't matter match, as there are many correct ways to pick roots in infinite loops, and to relax this assumption. That should enable us to recalculate postdominators less frequently.
This patch is pretty conservative when it comes to incremental updates on reverse-unreachable regions and ends up recalculating the whole tree in many cases. It should be possible to improve the performance in many cases, if we decide that it's important enough.
That being said, my experiments showed that reverse-unreachable are very rare in the IR emitted by clang when bootstrapping clang. Here are the statistics I collected by analyzing IR between passes and after each removePredecessor call:
```
# functions: 52283
# samples: 337609
# reverse unreachable BBs: 216022
# BBs: 247840796
Percent reverse-unreachable: 0.08716159869015269 %
Max(PercRevUnreachable) in a function: 87.58620689655172 %
# > 25 % samples: 471 ( 0.1395104988314885 % samples )
... in 145 ( 0.27733680163724345 % functions )
```
Most of the reverse-unreachable regions come from invalid IR where it wouldn't be possible to construct a PostDomTree anyway.
I would like to commit this patch in the next week in order to be able to complete the work that depends on it before the end of my internship, so please don't wait long to voice your concerns :).
Reviewers: dberlin, sanjoy, grosser, brzycki, davide, chandlerc, hfinkel
Reviewed By: dberlin
Subscribers: nhaehnle, javed.absar, kparzysz, uabelho, jlebar, hiraditya, llvm-commits, dberlin, david2050
Differential Revision: https://reviews.llvm.org/D35851
llvm-svn: 310940
Two minor savings: avoid copying the SinkAfter map and avoid moving a cast if it
is not needed.
Differential Revision: https://reviews.llvm.org/D36408
llvm-svn: 310910
This adds support non-canonical compare predicates. InstSimplify can't rely on canonicalization to have occurred.
Differential Revision: https://reviews.llvm.org/D36646
llvm-svn: 310893
This recommits r310869, with the moved files and no extra changes.
Original commit message:
This addresses a fixme in InstSimplify about using decomposeBitTest. This also fixes InstSimplify to handle ugt and ult compares too.
I've modified the interface a little to return only the APInt version of the mask that InstSimplify needs. InstCombine now has a small wrapper routine to create a Constant out of it. I've also dropped the returning of 0 since InstSimplify doesn't need that. So InstCombine creates a zero constant itself.
I also had to make decomposeBitTest support vectors since InstSimplify needs that.
As InstSimplify can't use something from the Transforms library, I've moved the CmpInstAnalysis code to the Analysis library.
Differential Revision: https://reviews.llvm.org/D36593
llvm-svn: 310889
localized to the code that uses those analyses.
Technically, this can change behavior as we no longer require the
existence of the ProfileSummaryInfo analysis to use local profile
information via BFI. We didn't actually require the PSI to have an
interesting profile though, so this only really impacts the behavior in
non-default pass pipelines.
IMO, this makes it substantially less surprising how everything works --
before an analysis that wasn't actually used had to exist to trigger
*any* profile aware inlining. I think the new organization makes it more
obvious where various checks for profile signals happen.
Differential Revision: https://reviews.llvm.org/D36710
llvm-svn: 310888
Failed to add the two files that moved. And then added an extra change I didn't mean to while trying to fix that. Reverting everything.
llvm-svn: 310873
This addresses a fixme in InstSimplify about using decomposeBitTest. This also fixes InstSimplify to handle ugt and ult compares too.
I've modified the interface a little to return only the APInt version of the mask that InstSimplify needs. InstCombine now has a small wrapper routine to create a Constant out of it. I've also dropped the returning of 0 since InstSimplify doesn't need that. So InstCombine creates a zero constant itself.
I also had to make decomposeBitTest support vectors since InstSimplify needs that.
As InstSimplify can't use something from the Transforms library, I've moved the CmpInstAnalysis code to the Analysis library.
Differential Revision: https://reviews.llvm.org/D36593
llvm-svn: 310869
This change let us schedule a bundle with different opcodes in it, for example : [ load, add, add, add ]
Reviewers: mkuper, RKSimon, ABataev, mzolotukhin, spatel, filcab
Subscribers: llvm-commits, rengolin
Differential Revision: https://reviews.llvm.org/D36518
llvm-svn: 310847
The assert was added with r310779 and is usually correct,
but as the test shows, not always. The 'volatile' on the
load is needed to expose the faulty path because without
it, DemandedBits would return that the load is just dead
rather than not demanded, and so we wouldn't hit the
bogus assert.
Also, since the lambda is just a single-line now, get rid
of it and inline the DB.isAllOnesValue() calls.
This should fix (prevent execution of a faulty assert):
https://bugs.llvm.org/show_bug.cgi?id=34179
llvm-svn: 310842
On some targets, the penalty of executing runtime unrolling checks
and then not the unrolled loop can be significantly detrimental to
performance. This results in the need to be more conservative with
the unroll count, keeping a trip count of 2 reduces the overhead as
well as increasing the chance of the unrolled body being executed. But
being conservative leaves performance gains on the table.
This patch enables the unrolling of the remainder loop introduced by
runtime unrolling. This can help reduce the overhead of misunrolled
loops because the cost of non-taken branches is much less than the
cost of the backedge that would normally be executed in the remainder
loop. This allows larger unroll factors to be used without suffering
performance loses with smaller iteration counts.
Differential Revision: https://reviews.llvm.org/D36309
llvm-svn: 310824
Updating remark API to newer OptimizationDiagnosticInfo API. This
allows remarks to show up in diagnostic yaml file, and enables use
of opt-viewer tool.
Hotness information for remarks (L505 and L751) do not display hotness
information, most likely due to profile information not being
propagated yet. Unsure if this is the desired outcome.
Patch by Tarun Rajendran.
Differential Revision: https://reviews.llvm.org/D36127
llvm-svn: 310763
This also corrects the description to match what was actually implemented. The old comment said X^(C1|C2), but it implemented X^((C1|C2)&~(C1&C2)). I believe ((C1|C2)&~(C1&C2)) is equivalent to (C1^C2).
Differential Revision: https://reviews.llvm.org/D36505
llvm-svn: 310658
We used to try to truncate the constant vector to vXi1, but if it's already i1 this would fail. Instead we now use IRBuilder::getZExtOrTrunc which should check the type and only create a trunc if needed. I believe this should trigger constant folding in the IRBuilder and ultimately do the same thing just with the additional type check.
llvm-svn: 310639
Current behavior is to transform these independently of the datalayout.
There's a proposal to change this in D35035:
https://reviews.llvm.org/D35035
llvm-svn: 310611
I couldn't find any smaller folds to help the cases in:
https://bugs.llvm.org/show_bug.cgi?id=34046
after:
rL310141
The truncated rotate-by-variable patterns elude all of the existing transforms because
of multiple uses and knowledge about demanded bits and knownbits that doesn't exist
without the whole pattern. So we need an unfortunately large pattern match. But by
simplifying this pattern in IR, the backend is already able to generate
rolb/rolw/rorb/rorw for x86 using its existing rotate matching logic (although
there is a likely extraneous 'and' of the rotate amount).
Note that rotate-by-constant doesn't have this problem - smaller folds should already
produce the narrow IR ops.
Differential Revision: https://reviews.llvm.org/D36395
llvm-svn: 310509
The recently improved support for `icmp` in ValueTracking
(r307304) exposes the fact that `isImplied` condition doesn't
really bail out if we hit the recursion limit (and calls
`computeKnownBits` which increases the depth and asserts).
Differential Revision: https://reviews.llvm.org/D36512
llvm-svn: 310481
When a new phi is generated for scalarpre of an expression, the phiTranslate cache
will become stale: Before PRE, the candidate expression must not be available in a
predecessor block, and phitranslate will cache the information. After PRE, the
expression will become available in all predecessor blocks, so the related entries
in phiTranslate cache becomes stale. The patch will simply remove the stale entries
so phiTranslate can be recomputed next time.
The stale entries in phitranslate cache will not affect correctness but will cause
missing PRE opportunity for later instructions.
Differential Revision: https://reviews.llvm.org/D36124
llvm-svn: 310421
Summary: Currently, ICP checks the count against a fixed value to see if it is hot enough to be promoted. This does not work for SamplePGO because sampled count may be much smaller. This patch uses PSI to check if the count is hot enough to be promoted.
Reviewers: davidxl, tejohnson, eraman
Reviewed By: davidxl
Subscribers: sanjoy, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D36341
llvm-svn: 310416
