This is another step towards getting rid of dyn_castNotVal,
so we can recommit:
https://reviews.llvm.org/rL300977
As the tests show, we were missing the lshr case for constants
and both ashr/lshr vector splat folds. The ashr case with constant
was being performed inefficiently in 2 steps. It's also possible
there was a latent bug in that case because we can't do that fold
if the constant is positive:
http://rise4fun.com/Alive/Bge
llvm-svn: 302465
We can simplify (or (icmp X, C1), (icmp X, C2)) to 'true' or one of the icmps in many cases.
I had to check some of these with Alive to prove to myself it's right, but everything seems
to check out. Eg, the deleted code in instcombine was completely ignoring predicates with
mismatched signedness.
This is a follow-up to:
https://reviews.llvm.org/rL301260https://reviews.llvm.org/D32143
llvm-svn: 302370
This adds routines for reseting KnownBits to unknown, making the value all zeros or all ones. It also adds methods for querying if the value is zero, all ones or unknown.
Differential Revision: https://reviews.llvm.org/D32637
llvm-svn: 302262
Change checkRippleForAdd from a heuristic to a full check -
if it is provable that the add does not overflow return true, otherwise false.
Patch by Yoav Ben-Shalom
Differential Revision: https://reviews.llvm.org/D32686
llvm-svn: 302093
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 adds zext, sext, and trunc methods to KnownBits and uses them where possible.
Differential Revision: https://reviews.llvm.org/D32784
llvm-svn: 302088
Summary:
Do three things to help with that:
- Add AttributeList::FirstArgIndex, which is an enumerator currently set
to 1. It allows us to change the indexing scheme with fewer changes.
- Add addParamAttr/removeParamAttr. This just shortens addAttribute call
sites that would otherwise need to spell out FirstArgIndex.
- Remove some attribute-specific getters and setters from Function that
take attribute list indices. Most of these were only used from
BuildLibCalls, and doesNotAlias was only used to test or set if the
return value is malloc-like.
I'm happy to split the patch, but I think they are probably easier to
review when taken together.
This patch should be NFC, but it sets the stage to change the indexing
scheme to this, which is more convenient when indexing into an array:
0: func attrs
1: retattrs
2...: arg attrs
Reviewers: chandlerc, pete, javed.absar
Subscribers: david2050, llvm-commits
Differential Revision: https://reviews.llvm.org/D32811
llvm-svn: 302060
This was originally checked in here:
https://reviews.llvm.org/rL301923
And reverted here:
https://reviews.llvm.org/rL301924
Because there's a clang test that would fail after this. I fixed/removed the
offending CHECK lines in:
https://reviews.llvm.org/rL301928
So let's try this again. Original commit message:
This is the fold that causes the infinite loop in BoringSSL
(https://github.com/google/boringssl/blob/master/crypto/cipher/e_rc2.c)
when we fix instcombine demanded bits to prefer 'not' ops as in https://reviews.llvm.org/D32255.
There are 2 or 3 problems with dyn_castNotVal, and I don't think we can
reinstate https://reviews.llvm.org/D32255 until dyn_castNotVal is completely eliminated.
1. As shown here, it transforms 'not' into random xor. This transform is harmful to SCEV and codegen because 'not' can often be folded while random xor cannot.
2. It does not transform vector constants. This is actually a good thing, but if you don't believe the above argument, then we shouldn't have excluded vectors.
3. It tries to avoid transforming not(not(X)). That's nice, but it doesn't match the greedy nature of instcombine. If we DeMorganize a pattern that has an extra 'not' in it: ~(~(~X) & Y) --> (~X | ~Y)
That's just another case of DeMorgan, so we should trust that we'll fold that pattern too: (~X | ~ Y) --> ~(X & Y)
Differential Revision: https://reviews.llvm.org/D32665
llvm-svn: 301929
This is the fold that causes the infinite loop in BoringSSL
(https://github.com/google/boringssl/blob/master/crypto/cipher/e_rc2.c)
when we fix instcombine demanded bits to prefer 'not' ops as in D32255.
There are 2 or 3 problems with dyn_castNotVal, and I don't think we can
reinstate D32255 until dyn_castNotVal is completely eliminated.
1. As shown here, it transforms 'not' into random xor. This transform is
harmful to SCEV and codegen because 'not' can often be folded while
random xor cannot.
2. It does not transform vector constants. This is actually a good thing,
but if you don't believe the above argument, then we shouldn't have
excluded vectors.
3. It tries to avoid transforming not(not(X)). That's nice, but it doesn't
match the greedy nature of instcombine. If we DeMorganize a pattern
that has an extra 'not' in it:
~(~(~X) & Y) --> (~X | ~Y)
That's just another case of DeMorgan, so we should trust that we'll fold
that pattern too:
(~X | ~ Y) --> ~(X & Y)
Differential Revision: https://reviews.llvm.org/D32665
llvm-svn: 301923
If we have ~(~X & Y), it only makes sense to transform it to (X | ~Y) when we do not need
the intermediate (~X & Y) value. In that case, we would need an extra instruction to
generate ~Y + 'or' (as shown in the test changes).
It's ok if we have multiple uses of ~X or Y, however. In those cases, we may not reduce the
instruction count or critical path, but we might improve throughput because we can generate
~X and ~Y in parallel. Whether that actually makes perf sense or not for a target is something
we can't answer in IR.
Differential Revision: https://reviews.llvm.org/D32703
llvm-svn: 301848
Summary: This patch adds isNegative, isNonNegative for querying whether the sign bit is known. It also adds makeNegative and makeNonNegative for controlling the sign bit.
Reviewers: RKSimon, spatel, davide
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32651
llvm-svn: 301747
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 patch uses various APInt methods to reduce temporary APInt creation.
This should be all of the unrelated cleanups that got buried in D32376(creating a KnownBits struct) as well as some pointed out by Simon during the review of that. Plus a few improvements to use counting instead of masking.
I've left out any places where we do something like (KnownZero & KnownOne) != 0 as I plan to add a helper method to KnownBits to ask that question and didn't want to thrash that code an additional time.
Differential Revision: https://reviews.llvm.org/D32495
llvm-svn: 301338
The matching here wasn't able to handle all the possible commutes. It always assumed the not would be on the left of the xor, but that's not guaranteed.
Differential Revision: https://reviews.llvm.org/D32474
llvm-svn: 301316
We can simplify (and (icmp X, C1), (icmp X, C2)) to one of the icmps in many cases.
I had to check some of these with Alive to prove to myself it's right, but everything
seems to check out. Eg, the code in instcombine was completely ignoring predicates with
mismatched signedness.
Handling or-of-icmps would be a follow-up step.
Differential Revision: https://reviews.llvm.org/D32143
llvm-svn: 301260
This is a straight cut and paste, but there's a bigger problem: if this
fold exists for simplifyOr, there should be a DeMorganized version for
simplifyAnd. But more than that, we have a patchwork of ad hoc logic
optimizations in InstCombine. There should be some structure to ensure
that we're not missing sibling folds across and/or/xor.
llvm-svn: 301213
There is logic to track the expected number of instructions
produced. It thought in this case an instruction would
be necessary to negate the result, but here it folded
into a ConstantExpr fneg when the non-undef value operand
was cancelled out by the second fsub.
I'm not sure why we don't fold constant FP ops with undef currently,
but I think that would also avoid this problem.
llvm-svn: 301199
Summary:
The return value of these intrinsics should always have 0 bits for
inactive threads. This means that when all arguments are constant
and the comparison evaluates to true, the intrinsic should return
the current exec mask.
Fixes some GL_ARB_shader_ballot tests.
Reviewers: arsenm
Subscribers: kzhuravl, wdng, yaxunl, dstuttard, tpr, llvm-commits, t-tye
Differential Revision: https://reviews.llvm.org/D32344
llvm-svn: 301195
We handled all of the commuted variants for plain xor already,
although they were scattered around and sometimes folded less
efficiently using distributive laws. We had no folds for not-xor.
Handling all of these patterns consistently is part of trying to
reinstate:
https://reviews.llvm.org/rL300977
llvm-svn: 301144
There's probably some better way to write this that eliminates the
code duplication without hurting readability, but at least this
eliminates the logic holes and is hopefully slightly more efficient
than creating new instructions.
llvm-svn: 301129
This reverts commit r301105, 4, 3 and 1, as a follow up of the previous
revert, which broke even more bots.
For reference:
Revert "[APInt] Use operator<<= where possible. NFC"
Revert "[APInt] Use operator<<= instead of shl where possible. NFC"
Revert "[APInt] Use ashInPlace where possible."
PR32754.
llvm-svn: 301111
The later uses of dyn_castNotVal in this block are either
incomplete (doesn't handle vector constants) or overstepping
(shouldn't handle constants at all), but this first use is
just unnecessary. 'I' is obviously not a constant, and it
can't be a not-of-a-not because that would already be
instsimplified.
llvm-svn: 301088
The bug was introduced by r301018 "[InstCombine] fadd double (sitofp x), y check that the promotion is valid". The patch didn't expect that fadd can be on vectors not necessarily scalars. Add vector support along with the test.
llvm-svn: 301070
Doing these transformations check that the result of integer addition is representable in the FP type.
(fadd double (sitofp x), fpcst) --> (sitofp (add int x, intcst))
(fadd double (sitofp x), (sitofp y)) --> (sitofp (add int x, y))
This is a fix for https://bugs.llvm.org//show_bug.cgi?id=27036
Reviewed By: andrew.w.kaylor, scanon, spatel
Differential Revision: https://reviews.llvm.org/D31182
llvm-svn: 301018
The demanded mask and the constant should always be the same width for all callers today.
Also stop copying the demanded mask as its passed in. We should avoid allocating memory unless we are going to do something. The final AND to create the new constant will take care of it.
llvm-svn: 300927
getSignBit is a static function that creates an APInt with only the sign bit set. getSignMask seems like a better name to convey its functionality. In fact several places use it and then store in an APInt named SignMask.
Differential Revision: https://reviews.llvm.org/D32108
llvm-svn: 300856
This question comes up in many places in SimplifyDemandedBits. This makes it easy to ask without allocating additional temporary APInts.
The BitVector class provides a similar functionality through its (IMHO badly named) test(const BitVector&) method. Though its output polarity is reversed.
I've provided one example use case in this patch. I plan to do more as a follow up.
Differential Revision: https://reviews.llvm.org/D32258
llvm-svn: 300851
Currently we don't explicitly process ConstantDataSequential, ConstantAggregateZero, or ConstantVector, or Undef before applying the Depth limit. Instead they occur after the depth check in the non-instruction path.
For the constant types that we do handle, the code is replicated from computeKnownBits.
This patch fixes the missing constant handling and the reduces the amount of code by just using computeKnownBits directly for any type of Constant.
Differential Revision: https://reviews.llvm.org/D32123
llvm-svn: 300849
This change is correct because the verifier requires that at most one
argument be marked 'sret'.
NFC, removes a use of AttributeList slot APIs.
llvm-svn: 300784
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
This patch uses lshrInPlace to replace code where the object that lshr is called on is being overwritten with the result.
This adds an lshrInPlace(const APInt &) version as well.
Differential Revision: https://reviews.llvm.org/D32155
llvm-svn: 300566
So, `cast<Instruction>` is not guaranteed to succeed. Change the
code so that we create a new constant and use it in the newly
created instruction, as it's done in other places in InstCombine.
OK'ed by Sanjay/Craig. Fixes PR32686.
llvm-svn: 300495
Causes some VGPR usage improvements in shaderdb, but
introduces some SGPR spilling regressions due to random
scheduling changes later.
llvm-svn: 300453
If we already called computeKnownBits for the RHS being a constant power of 2, we've already computed everything we can and should just stop. I think previously we would still recurse if we had determined the result was negative or had not determined the sign bit at all.
llvm-svn: 300432
This patch adds new optimization (Folding cmp(sub(a,b),0) into cmp(a,b))
to instCombineCall pass and was written specific for X86 CMP intrinsics.
Differential Revision: https://reviews.llvm.org/D31398
llvm-svn: 300422
When checking if we should return a constant, we create some temporary APInts to see if we know all bits. But the exact computations we do are needed in several other locations in the same code.
This patch moves them to named temporaries so we can reuse them.
Ideally we'd write directly to KnownZero/One, but we currently seem to only write those variables after all the simplifications checks and I didn't want to change that with this patch.
Differential Revision: https://reviews.llvm.org/D32094
llvm-svn: 300376
This avoids the confusing 'CS.paramHasAttr(ArgNo + 1, Foo)' pattern.
Previously we were testing return value attributes with index 0, so I
introduced hasReturnAttr() for that use case.
llvm-svn: 300367
...when C1 differs from C2 by one bit and C1 <u C2:
http://rise4fun.com/Alive/Vuo
And move related folds to a helper function. This reduces code duplication and
will make it easier to remove the scalar-only restriction as a follow-up step.
llvm-svn: 300364
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
Add hasParamAttribute() and use it instead of hasAttribute(ArgNo+1,
Kind) everywhere.
The fact that the AttributeList index for an argument is ArgNo+1 should
be a hidden implementation detail.
NFC
llvm-svn: 300272
Switch from Euclid's algorithm to Stein's algorithm for computing GCD. This
avoids the (expensive) APInt division operation in favour of bit operations.
Remove all memory allocation from within the GCD loop by tweaking our `lshr`
implementation so it can operate in-place.
Differential Revision: https://reviews.llvm.org/D31968
llvm-svn: 300252
Summary:
Bug noticed by inspection.
Extend the test to handle invokes as well as calls, and rewrite it to
not depend on the inliner and other passes.
Also simplify the call site replacement code with CallSite, similar to
what I did to dead arg elimination and arg promotion (rL300235 and
rL300229).
Reviewers: danielcdh, davidxl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32041
llvm-svn: 300251
This is effectively a retry of:
https://reviews.llvm.org/rL299851
but now we have tests and an assert to make sure the bug
that was exposed with that attempt will not happen again.
I'll fix the code duplication and missing sibling fold next,
but I want to make this change as small as possible to reduce
risk since I messed it up last time.
This should fix:
https://bugs.llvm.org/show_bug.cgi?id=32524
llvm-svn: 300236
It's less efficient to produce 'ule' than 'ult' since we know we're going to
canonicalize to 'ult', but we shouldn't have duplicated code for these folds.
As a trade-off, this was a pretty terrible way to make a '2'. :)
if (LHSC == SubOne(RHSC))
AddC = ConstantExpr::getSub(AddOne(RHSC), LHSC);
The next steps are to share the code to fix PR32524 and add the missing 'and'
fold that was left out when PR14708 was fixed:
https://bugs.llvm.org/show_bug.cgi?id=14708
llvm-svn: 300222
This seems like a much more natural API, based on Derek Schuff's
comments on r300015. It further hides the implementation detail of
AttributeList that function attributes come last and appear at index
~0U, which is easy for the user to screw up. git diff says it saves code
as well: 97 insertions(+), 137 deletions(-)
This also makes it easier to change the implementation, which I want to
do next.
llvm-svn: 300153
This replicates the known bits and constant creation code from the single use case for these instructions and adds it here. The computeKnownBits and constant creation code for other instructions is now in the default case of the opcode switch.
llvm-svn: 300094
We already handled a superset check that included the known ones too and folded to a constant that may include ones. But it can also handle the case of no ones.
llvm-svn: 300093
As discussed in:
https://bugs.llvm.org/show_bug.cgi?id=32486
...the canonicalization of vector select to shufflevector does not hold up
when undef elements are present in the condition vector.
Try to make the undef handling clear in the code and the LangRef.
Differential Revision: https://reviews.llvm.org/D31980
llvm-svn: 300092
Currently if we reach an instruction with multiples uses we know we can't do any optimizations to that instruction itself since we only have the demanded bits for one of the users. But if we know all of the bits are zero/one for that one user we can still go ahead and create a constant to give to that user.
This might then reduce the instruction to having a single use and allow additional optimizations on the other path.
This picks up an additional case that r300075 didn't catch.
Differential Revision: https://reviews.llvm.org/D31552
llvm-svn: 300084
If we are adding/subtractings 0s below the highest demanded bit we can just use the other operand and remove the operation.
My primary motivation is observing that we can call ShrinkDemandedConstant for the add/sub and create a 0 constant, rather than removing the add completely. In the case I saw, we modified the constant on an add instruction to a 0, but the add is not put into the worklist. So we didn't revisit it until the next InstCombine iteration. This caused an IR modification to remove add and a subsequent iteration to be ran.
With this change we get bypass the add in the first iteration and prevent the second iteration from changing anything.
Differential Revision: https://reviews.llvm.org/D31120
llvm-svn: 300075
One potential way to make InstCombine (very slightly?) faster is to recycle instructions
when possible instead of creating new ones. It's not explicitly stated AFAIK, but we don't
consider this an "InstSimplify". We could, however, make a new layer to house transforms
like this if that makes InstCombine more manageable (just throwing out an idea; not sure
how much opportunity is actually here).
Differential Revision: https://reviews.llvm.org/D31863
llvm-svn: 300067
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
Summary:
For now, it just wraps AttributeSetNode*. Eventually, it will hold
AvailableAttrs as an inline bitset, and adding and removing enum
attributes will be super cheap.
This sinks AttributeSetNode back down to lib/IR/AttributeImpl.h.
Reviewers: pete, chandlerc
Subscribers: llvm-commits, jfb
Differential Revision: https://reviews.llvm.org/D31940
llvm-svn: 300014
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
This re-lands r299875.
I introduced a bug in Clang code responsible for replacing K&R, no
prototype declarations with a real function definition with a prototype.
The bug was here:
// Collect any return attributes from the call.
- if (oldAttrs.hasAttributes(llvm::AttributeList::ReturnIndex))
- newAttrs.push_back(llvm::AttributeList::get(newFn->getContext(),
- oldAttrs.getRetAttributes()));
+ newAttrs.push_back(oldAttrs.getRetAttributes());
Previously getRetAttributes() carried AttributeList::ReturnIndex in its
AttributeList. Now that we return the AttributeSetNode* directly, it no
longer carries that index, and we call this overload with a single node:
AttributeList::get(LLVMContext&, ArrayRef<AttributeSetNode*>)
That aborted with an assertion on x86_32 targets. I added an explicit
triple to the test and added CHECKs to help find issues like this in the
future sooner.
llvm-svn: 299899
Summary:
AttributeList::get(Fn|Ret|Param)Attributes no longer creates a temporary
AttributeList just to hide the AttributeSetNode type.
I've also added a factory method to create AttributeLists from a
parallel array of AttributeSetNodes. I think this simplifies
construction of AttributeLists when rewriting function prototypes.
Previously we would test if a particular index had attributes, and
conditionally add a temporary attribute list to a vector. Now the
attribute set vector is parallel to the argument vector already that
these passes already construct.
My long term vision is to wrap AttributeSetNode* inside an AttributeSet
type that holds the enum attributes, but that will come in a follow up
change.
I haven't done any performance measurements for this change because
profiling hasn't shown that any of the affected code is hot.
Reviewers: pete, chandlerc, sanjoy, hfinkel
Reviewed By: pete
Subscribers: jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D31198
llvm-svn: 299875
Also, make the same change in and-of-icmps and remove a hack for detecting that case.
Finally, add some FIXME comments because the code duplication here is awful.
This should fix the remaining IR problem noted in:
https://bugs.llvm.org/show_bug.cgi?id=32524
llvm-svn: 299851
We currently only fold scalar add of constants into selects. This improves this to support vectors too.
Differential Revision: https://reviews.llvm.org/D31683
llvm-svn: 299847
Summary:
This is my first time using the commutable matchers so wanted to make sure I was doing it right.
Are there any other matcher tricks to further shrink this? Can we commute the whole match so we don't have to LHS and RHS separately?
Reviewers: davide, spatel
Reviewed By: davide
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31680
llvm-svn: 299840
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
"PredicatesFoldable" returns false for signed/unsigned mismatched pairs,
so these cases should never exist. We'll default to 'unreachable' on those
predicate combos instead.
Most of what's left in these switches belongs in InstSimplify (and may
already be there), so there's probably more that can be done to reduce
this code.
llvm-svn: 299829
Calling computeKnownBits on the RHS should allows us to recurse one step further. isMask is equivalent to the isPowerOf2(C+1) except in the case where C is all ones. But that was already handled earlier by creating a not which is an Xor with all ones. So this should be fine.
llvm-svn: 299710
This combine is fully handled by SimplifyDemandedInstructionBits as of r299658 where I fixed this code to ensure the Add/Sub had only a single user. Otherwise it would fire and create additional instructions. That fix resulted in an improvement to code generated for tsan which is why I committed it before deleting.
Differential Revision: https://reviews.llvm.org/D31543
llvm-svn: 299704
There must be some opportunity to refactor big chunks of nearly duplicated code in FoldOrOfICmps / FoldAndOfICmps.
Also, none of this works with vectors, but it should.
llvm-svn: 299568
Currently we only fold with ConstantInt RHS. This generalizes to any Constant RHS.
Differential Revision: https://reviews.llvm.org/D31610
llvm-svn: 299466
It turns out that SimplifyDemandedInstructionBits will get called earlier and remove bits from C1 first. Effectively doing (X & (C1&C2)) | C2. So by the time it got to this check there could be no common bits.
I think the DAGCombiner has the same check but its check can be executed because it handles demanded bits later. I'll look at it next.
llvm-svn: 299384
1. Improve enum, function, and variable names.
2. Improve comments.
3. Fix variable capitalization.
4. Run clang-format.
As an existing code comment suggests, this should work with vector types / splat constants too,
so making this look right first will reduce the diffs needed for that change.
llvm-svn: 299365
This moves the isMask and isShiftedMask functions to be class methods. They now use the MathExtras.h function for single word size and leading/trailing zeros/ones or countPopulation for the multiword size. The previous implementation made multiple temorary memory allocations to do the bitwise arithmetic operations to match the MathExtras.h implementation.
Differential Revision: https://reviews.llvm.org/D31565
llvm-svn: 299362
The callers have already performed the necessary cast before calling. This allows us to remove a comment that says the instruction must be a BinaryOperator and make it explicit in the argument type.
Had to add a default case to the switch because BinaryOperator::getOpcode() returns a BinaryOps enum.
llvm-svn: 299339
As far as I can tell this combine is fully handled by SimplifyDemandedInstructionBits.
I was only looking at this because it is the only user of APIntOps::isShiftedMask which is itself broken. As demonstrated by r299187. I was going to fix isShiftedMask and needed to make sure we had coverage for the new cases it would expose to this combine. But looks like we can nuke it instead.
Differential Revision: https://reviews.llvm.org/D31543
llvm-svn: 299337
This removes a parameter from the routine that was responsible for a lot of the issue. It was a bit count that had to be set to the BitWidth of the APInt and would get passed to getLowBitsSet. This guaranteed the call to getLowBitsSet would create an all ones value. This was then compared to (V | (V-1)). So the only shifted masks we detected had to have the MSB set.
The one in tree user is a transform in InstCombine that never fires due to earlier transforms covering the case better. I've submitted a patch to remove it completely, but for now I've just adapted it to the new interface for isShiftedMask.
llvm-svn: 299273
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
A common way to implement nearbyint is by fiddling with the floating
point environment and calling rint. This is used at least by the BSD
libm and musl. As such, canonicalizing the latter to the former will
create infinite loops for libm and generally pessimize performance, at
least when the generic C versions are used.
This change preserves the rint in the libcall translation and also
handles the domain truncation logic, so that rint with float argument
will be reduced to rintf etc.
llvm-svn: 299247
Summary: Currently the VP metadata was dropped when InstCombine converts a call to direct call. This patch converts the VP metadata to branch_weights so that its hotness is recorded.
Reviewers: eraman, davidxl
Reviewed By: davidxl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31344
llvm-svn: 299228
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
Sanjay Patel