This patch adds min/max population count, leading/trailing zero/one bit counting methods.
The min methods return answers based on bits that are known without considering unknown bits. The max methods give answers taking into account the largest count that unknown bits could give.
Differential Revision: https://reviews.llvm.org/D32931
llvm-svn: 302925
This patch adds isConstant and getConstant for determining if KnownBits represents a constant value and to retrieve the value. Use them to simplify code.
Differential Revision: https://reviews.llvm.org/D32785
llvm-svn: 302091
This patch introduces a new KnownBits struct that wraps the two APInt used by computeKnownBits. This allows us to treat them as more of a unit.
Initially I've just altered the signatures of computeKnownBits and InstCombine's simplifyDemandedBits to pass a KnownBits reference instead of two separate APInt references. I'll do similar to the SelectionDAG version of computeKnownBits/simplifyDemandedBits as a separate patch.
I've added a constructor that allows initializing both APInts to the same bit width with a starting value of 0. This reduces the repeated pattern of initializing both APInts. Once place default constructed the APInts so I added a default constructor for those cases.
Going forward I would like to add more methods that will work on the pairs. For example trunc, zext, and sext occur on both APInts together in several places. We should probably add a clear method that can be used to clear both pieces. Maybe a method to check for conflicting information. A method to return (Zero|One) so we don't write it out everywhere. Maybe a method for (Zero|One).isAllOnesValue() to determine if all bits are known. I'm sure there are many other methods we can come up with.
Differential Revision: https://reviews.llvm.org/D32376
llvm-svn: 301432
Commits were:
"Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts"
"Add a new WeakVH value handle; NFC"
"Rename WeakVH to WeakTrackingVH; NFC"
The changes assumed pointers are 8 byte aligned on all architectures.
llvm-svn: 301429
Summary:
I plan to use WeakVH to mean "nulls itself out on deletion, but does
not track RAUW" in a subsequent commit.
Reviewers: dblaikie, davide
Reviewed By: davide
Subscribers: arsenm, mehdi_amini, mcrosier, mzolotukhin, jfb, llvm-commits, nhaehnle
Differential Revision: https://reviews.llvm.org/D32266
llvm-svn: 301424
The code I've removed here exists in ExpandBinOp in InstSimplify which we call into before SimplifyUsingDistributiveLaws. The code in InstSimplify looks to have been copied from here.
I verified this code doesn't fire on any lit tests. Not that that proves its definitely dead.
Differential Revision: https://reviews.llvm.org/D32472
llvm-svn: 301341
This is preparation for a clang change to improve the [[nodiscard]] warning to not be ignored on methods that return a class marked [[nodiscard]] that are defined in the class itself. See D32207.
We should consider adding wrapper methods to APInt that return the overflow flag directly and discard the APInt result. This would eliminate the void casts and the need to create a bool before the call to pass to the out param.
llvm-svn: 300758
We currently only support folding a subtract into a select but not a PHI. This fixes that.
I had to fix an assumption in FoldOpIntoPhi that assumed the PHI node was always in operand 0. Now we pass it in like we do for FoldOpIntoSelect. But we still require some dancing to find the Constant when we create the BinOp or ConstantExpr. This is based code is similar to what we do for selects.
Since I touched all call sites, this also renames FoldOpIntoPhi to foldOpIntoPhi to match coding standards.
Differential Revision: https://reviews.llvm.org/D31686
llvm-svn: 300363
Currently this code always makes 2 or 3 calls to tryFactorization regardless of whether the LHS/RHS are BinaryOperators. We make 3 calls when both operands are BinaryOperators with the same opcode. Or surprisingly, when neither are BinaryOperators. This is because getBinOpsForFactorization returns Instruction::BinaryOpsEnd when the operand is not a BinaryOperator. If both LHS and RHS are not BinaryOperators then they both have an Opcode of Instruction::BinaryOpsEnd. When this happens we rely on tryFactorization to early out due to A/B/C/D being null. Similar behavior occurs for the other calls, we rely on getBinOpsForFactorization having made A/B or C/D null to get tryFactorization to early out.
We also rely on these null checks to check the result of getIdentityValue and early out for it.
This patches refactors this to pull these checks up to SimplifyUsingDistributiveLaws so we don't rely on BinaryOpsEnd as a sentinel or this A/B/C/D null behavior. I think this makes this code easier to reason about. Should also give a tiny performance improvement for cases where the LHS or RHS isn't a BinaryOperator.
Differential Revision: https://reviews.llvm.org/D31913
llvm-svn: 300353
and to expose a handle to represent the actual case rather than having
the iterator return a reference to itself.
All of this allows the iterator to be used with common STL facilities,
standard algorithms, etc.
Doing this exposed some missing facilities in the iterator facade that
I've fixed and required some work to the actual iterator to fully
support the necessary API.
Differential Revision: https://reviews.llvm.org/D31548
llvm-svn: 300032
This removes a TODO in getIdentityValue and may allow some transforms to occur earlier. But I was unable to find any transforms we didn't already handle.
llvm-svn: 299966
Summary: I noticed in the select folding code that we copied fast math flags, but did not do the same for the similar handling in phi nodes. This patch fixes that to do the same thing as select
Reviewers: spatel, davide, majnemer, hfinkel
Reviewed By: davide
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31690
llvm-svn: 299838
This way we ensure we immediately revisit the instruction and do any additional optimizations before visiting the users. Otherwise we might visit the users, then the instruction, then users again, then instruction again.
llvm-svn: 299267
Some of the GEP combines (e.g., descaling) can't handle vector GEPs. We have an
existing check that attempts to bail out if given a vector GEP. However, the
check only tests the GEP's pointer operand. A GEP results in a vector of
pointers if at least one of its operands is vector-typed (e.g., its pointer
operand could be a scalar, but its index could be a vector). We should just
check the type of the GEP itself. This should fix PR32414.
Reference: https://bugs.llvm.org/show_bug.cgi?id=32414
Differential Revision: https://reviews.llvm.org/D31470
llvm-svn: 299017
Summary:
We are incorrectly folding selects into phi nodes when the incoming value of a phi
node is a constant vector. This optimization is done in `FoldOpIntoPhi` when the
select condition is a phi node with constant incoming values.
Without the fix, we are miscompiling (i.e. incorrectly folding the
select into the phi node) when the vector contains non-zero
elements.
This patch fixes the miscompile and we will correctly fold based on the
select vector operand (see added test cases).
Reviewers: majnemer, sanjoy, spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31189
llvm-svn: 298845
InstCombine tries to constant fold instruction operands during worklist building, but we don't print that we're doing this.
We also set a change flag here that causes us to rebuild and rerun the worklist one more time even if processing the worklist itself created no additional changes. So in the log I saw two inst combine runs that visited all instructions without printing that anything was changed. I may be submitting another patch to remove the change flag unless I can find some reason why we should be doing that.
Differential Revision: https://reviews.llvm.org/D31091
llvm-svn: 298264
This patch is based on the llvm-dev discussion here:
http://lists.llvm.org/pipermail/llvm-dev/2017-January/109631.html
Folding to i1 should always be desirable because that's better for value tracking
and we have special folds for i1 types.
I checked for other users of shouldChangeType() where this might have an effect,
but we already handle the i1 case differently than other types in all of those cases.
Side note: the default datalayout includes i1, so it seems we only find this gap in
shouldChangeType + phi folding for the case when there is (1) an explicit datalayout
without i1, (2) casting to i1 from a legal type, and (3) a phi with exactly 2 incoming
casted operands (as Björn mentioned).
Differential Revision: https://reviews.llvm.org/D29336
llvm-svn: 294066
a function's CFG when that CFG is unchanged.
This allows transformation passes to simply claim they preserve the CFG
and analysis passes to check for the CFG being preserved to remove the
fanout of all analyses being listed in all passes.
I've gone through and removed or cleaned up as many of the comments
reminding us to do this as I could.
Differential Revision: https://reviews.llvm.org/D28627
llvm-svn: 292054
mark it as never invalidated in the new PM.
The old PM already required this to work, and after a discussion with
Hal this seems to really be the only sensible answer. The cache
gracefully degrades as the IR is mutated, and most things which do this
should already be incrementally updating the cache.
This gets rid of a bunch of logic preserving and testing the
invalidation of this analysis.
llvm-svn: 292039
cover domtree and alias analysis. These are the pretty clear analyses
that we would always want to survive this pass.
To make these survive, we also need to preserve the assumption cache.
Added a test that verifies the important bits of this preservation.
llvm-svn: 292037
Some of the callers are artificially limiting this transform to integer types;
this should make it easier to incrementally remove that restriction.
llvm-svn: 291620
We're currently doing nearly the same thing for @llvm.objectsize in
three different places: two of them are missing checks for overflow,
and one of them could subtly break if InstCombine gets much smarter
about removing alloc sites. Seems like a good idea to not do that.
llvm-svn: 290214
After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is more computationally efficient, and also we need much less
code...
llvm-svn: 289756
We could truncate the condition and then try to fold the add into the
original condition value causing wrong case constants to be used.
Move the offset transform ahead of the truncate transform and return
after each transform, so there's no chance of getting confused values.
Fix for:
https://llvm.org/bugs/show_bug.cgi?id=31260
llvm-svn: 289442
Instead, expose whether the current type is an array or a struct, if an array
what the upper bound is, and if a struct the struct type itself. This is
in preparation for a later change which will make PointerType derive from
Type rather than SequentialType.
Differential Revision: https://reviews.llvm.org/D26594
llvm-svn: 288458
As discussed by Andrea on PR30486, we have an unsafe cast to an Instruction type in the select combine which doesn't take into account that it could be a ConstantExpr instead.
Differential Revision: https://reviews.llvm.org/D25466
llvm-svn: 284000
computeKnownBits() already works for integer vectors, so allow vector types when calling that from InstCombine.
I don't think the change to use m_APInt in computeKnownBits is strictly necessary because we do check for
ConstantVector later, but it's more efficient to handle the splat case without needing to loop on vector elements.
This should work with InstSimplify, but doesn't yet, so I made that a FIXME comment on the test for PR24942:
https://llvm.org/bugs/show_bug.cgi?id=24942
Differential Revision: https://reviews.llvm.org/D24677
llvm-svn: 281777
Summary: We can allow sinking if the single user block has only one unique predecessor, regardless of the number of edges. Note that a switch statement with multiple cases can have the same destination.
Reviewers: mcrosier, majnemer, spatel, reames
Subscribers: reames, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D23722
llvm-svn: 279448
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.
llvm-svn: 278077
Summary:
Turn (select C, (sext A), B) into (sext (select C, A, B')) when A is i1 and
B is a compatible constant, also for zext instead of sext. This will then be
further folded into logical operations.
The transformation would be valid for non-i1 types as well, but other parts of
InstCombine prefer to have sext from non-i1 as an operand of select.
Motivated by the shader compiler frontend in Mesa for AMDGPU, which emits i32
for boolean operations. With this change, the boolean logic is fully
recovered.
Reviewers: majnemer, spatel, tstellarAMD
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D22747
llvm-svn: 277801
Add a generalized IRBuilderCallbackInserter, which is just given a
callback to execute after insertion. This can be used to get rid of
the custom inserter in InstCombine, which will in turn allow me to add
target specific InstCombineCalls API for intrinsics without horrible
layering violations.
llvm-svn: 277784
A ConstantVector can have ConstantExpr operands and vice versa.
However, the folder had no ability to fold ConstantVectors which, in
some cases, was an optimization barrier.
Instead, rephrase the folder in terms of Constants instead of
ConstantExprs and teach callers how to deal with failure.
llvm-svn: 277099
Just because we can constant fold the result of an instruction does not
imply that we can delete the instruction. It may have side effects.
This fixes PR28655.
llvm-svn: 276389
This is a partial implementation of a general fold for associative+commutative operators:
(op (cast (op X, C2)), C1) --> (cast (op X, op (C1, C2)))
(op (cast (op X, C2)), C1) --> (op (cast X), op (C1, C2))
There are 7 associative operators and 13 cast types, so this could potentially go a lot further.
Differential Revision: https://reviews.llvm.org/D22421
llvm-svn: 275684
This adds support to the backed to actually support SjLj EH as an exception
model. This is *NOT* the default model, and requires explicitly opting into it
from the frontend. GCC supports this model and for MinGW can still be enabled
via the `--using-sjlj-exceptions` options.
Addresses PR27749!
llvm-svn: 271244
The original commit was reverted because of a buildbot problem with LazyCallGraph::SCC handling (not related to the OptBisect handling).
Differential Revision: http://reviews.llvm.org/D19172
llvm-svn: 267231
Summary:
We can fold compares to false when two distinct allocations within a
function are compared for equality.
Patch by Anna Thomas!
Reviewers: majnemer, reames, sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D19390
llvm-svn: 267214
Summary:
If we know that the pointer allocated within a function does not escape,
we can fold away comparisons that are done with global pointers
Patch by Anna Thomas!
Reviewers: reames, majnemer, sanjoy
Subscribers: mgrang, mcrosier, majnemer, llvm-commits
Differential Revision: http://reviews.llvm.org/D19276
llvm-svn: 267035
This patch implements a optimization bisect feature, which will allow optimizations to be selectively disabled at compile time in order to track down test failures that are caused by incorrect optimizations.
The bisection is enabled using a new command line option (-opt-bisect-limit). Individual passes that may be skipped call the OptBisect object (via an LLVMContext) to see if they should be skipped based on the bisect limit. A finer level of control (disabling individual transformations) can be managed through an addition OptBisect method, but this is not yet used.
The skip checking in this implementation is based on (and replaces) the skipOptnoneFunction check. Where that check was being called, a new call has been inserted in its place which checks the bisect limit and the optnone attribute. A new function call has been added for module and SCC passes that behaves in a similar way.
Differential Revision: http://reviews.llvm.org/D19172
llvm-svn: 267022
commit ae14bf6488e8441f0f6d74f00455555f6f3943ac
Author: Mehdi Amini <mehdi.amini@apple.com>
Date: Fri Mar 11 17:15:50 2016 +0000
Remove PreserveNames template parameter from IRBuilder
Summary:
Following r263086, we are now relying on a flag on the Context to
discard Value names in release builds.
Reviewers: chandlerc
Subscribers: mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D18023
From: Mehdi Amini <mehdi.amini@apple.com>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263258
91177308-0d34-0410-b5e6-96231b3b80d8
until we can figure out what to do about clang and Release build testing.
This reverts commit 263258.
llvm-svn: 263321
Summary:
Following r263086, we are now relying on a flag on the Context to
discard Value names in release builds.
Reviewers: chandlerc
Subscribers: mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D18023
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 263258
This was originally a pointer to support pass managers which didn't use
AnalysisManagers. However, that doesn't realistically come up much and
the complexity of supporting it doesn't really make sense.
In fact, *many* parts of the pass manager were just assuming the pointer
was never null already. This at least makes it much more explicit and
clear.
llvm-svn: 263219
As part of r251146 InstCombine was extended to call computeKnownBits on
every value in the function to determine whether it happens to be
constant. This increases typical compiletime by 1-3% (5% in irgen+opt
time) in my measurements. On the other hand this case did not trigger
once in the whole llvm-testsuite.
This patch introduces the notion of ExpensiveCombines which are only
enabled for OptLevel > 2. I removed the check in InstructionSimplify as
that is called from various places where the OptLevel is not known but
given the rarity of the situation I think a check in InstCombine is
enough.
Differential Revision: http://reviews.llvm.org/D16835
llvm-svn: 263047
Original commit message:
calculate builtin_object_size if argument is a removable pointer
This patch fixes calculating correct value for builtin_object_size function
when pointer is used only in builtin_object_size function call and never
after that.
Patch by Strahinja Petrovic.
Differential Revision: http://reviews.llvm.org/D17337
Reland the original change with a small modification (first do a null check
and then do the cast) to satisfy ubsan.
llvm-svn: 263011
Summary: SampleProfile pass needs to be performed after InstructionCombiningPass, which helps eliminate un-inlinable function calls.
Reviewers: davidxl, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D17742
llvm-svn: 262419
This patch fixes calculating correct value for builtin_object_size function
when pointer is used only in builtin_object_size function call and never
after that.
Patch by Strahinja Petrovic.
Differential Revision: http://reviews.llvm.org/D17337
llvm-svn: 262337
more places to prevent gratuitous re-"runs" of these passes.
The passes themselves don't do any work when run, but we keep spending
time scheduling and running these needlessly when we really don't need
to do so.
This is the first patch towards fixing the really horrible loop pass
pipeline fragmentation pointed out by Sanjoy in PR24804.
llvm-svn: 261302
InstCombine and SCCP both want to remove dead code in a very particular
way but using identical means to do so. Share the code between the two.
No functionality change is intended.
llvm-svn: 258653
Summary:
GEPOperator: provide getResultElementType alongside getSourceElementType.
This is made possible by adding a result element type field to GetElementPtrConstantExpr, which GetElementPtrInst already has.
GEP: replace get(Pointer)ElementType uses with get{Source,Result}ElementType.
Reviewers: mjacob, dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16275
llvm-svn: 258145
Summary: This patch fixes a bug in prepareICWorklistFromFunction, where the loop becomes infinite with instructions of token type. The patch checks if the instruction is token type, and if so it updates EndInst with the current instruction.
Reviewers: reames, majnemer
Subscribers: llvm-commits, sanjoy
Differential Revision: http://reviews.llvm.org/D15859
llvm-svn: 256792
For non padded structs, we can just proceed and deaggregate them.
We don't want ot do this when there is padding in the struct as to not
lose information about this padding (the subsequents passes would then
try hard to preserve the padding, which is undesirable).
Also update extractvalue.ll and cast.ll so that they use structs with padding.
Remove the FIXME in the extractvalue of laod case as the non padded case is
handled when processing the load, and we don't want to do it on the padded
case.
Patch by: Amaury SECHET <deadalnix@gmail.com>
Differential Revision: http://reviews.llvm.org/D14483
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 255600
The instruction combiner previously removed types from filter clauses in Landing Pad instructions if the type had previously been seen in a catch clause. This is incorrect and prevents unexpected exception handlers from rethrowing the caught type.
Differential Revision: http://reviews.llvm.org/D14669
llvm-svn: 253370
Craig Topper