memcpy has clamped dst stack alignment to NaturalStackAlignment if
hasStackRealignment is false. We should also clamp stack alignment
for memset and memmove. If we don't clamp, SelectionDAG may first
do tail call optimization which requires no stack realignment. Then
memmove, memset in same function may be lowered to load/store with
larger alignment leading to PEI emit stack realignment code which
is absolutely not correct.
Reviewed By: LuoYuanke
Differential Revision: https://reviews.llvm.org/D136456
Functions with `aarch64_sme_pstatesm_body` will emit a SMSTART at the start
of the function, and a SMSTOP at the end of the function, such that all
operations use the right value for vscale.
Because the placement of these nodes is critically important (i.e. no
vscale-dependent operations should be done before SMSTART has been issued),
we require glueing the CopyFromReg to the Entry node such that we can
insert the SMSTART as part of that glued chain.
More details about the SME attributes and design can be found
in D131562.
Reviewed By: aemerson
Differential Revision: https://reviews.llvm.org/D131582
The previous code used a APInt(1, 0) to represent the demanded elts of a scalable vector, and then ignored that argument if type was scalable. This was inconsistent with the UndefElts parameter which is set to either APInt(1, 0) or APInt(1,1) - that is, implicitly broadcast across all lanes. Particularly since the undef code relied on the DemandedElts parameter having bitwidth 1 to achieve that result!
This change switches the demanded parameter to APInt(1,1), documents the broadcast semantics, and takes advantage of it to remove one special case for scalable vectors which is no longer required.
Update comment, and add an assertion to check property expected by sole (non-test) caller. Remove tests which appear to have been copied from fixed vector tests, and whose demanded bits don't correspond to the way this interface is otherwise used.
We can still get a NaN even if none of the operands are NaN,
e.g. from +inf/-inf. D50804 didn't catch that.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D134854
We have a very common pattern of dispatching between BUILD_VECTOR and SPLAT_VECTOR creation repeated in many cases in code. Common the pattern into a utility function.
The code introduced in https://reviews.llvm.org/D130881 has a bug as it may cause a use-after-free error that can be caught by ASAN.
The bug essentially boils down to iterator invalidation of `DenseMap`. The expression `SDEI[To] = I->second;` may cause `SDEI` to grow if `To` is inserted for the very first time. When that happens, all existing iterators to the map are invalidated as their backing storage has been freed. Accessing `I->second` is then invalid and attempts to access freed memory (as `I` is an iterator of `SDEI`).
This patch fixes that quite simply by first making a copy of `I->second`, and then moving into the possibly newly inserted KV of the ` DenseMap`.
No test attached as I am not sure it is practible to test.
Differential revision: https://reviews.llvm.org/D135019
Includes handling of constants with vector type in isKnownNeverNaN.
For AMDGPU results in not making fcanonicalize during legalization
for vector inputs to fmaxnum_ieee and fminnum_ieee. Does not affect
end result since there is a combine that eliminates fcanonicalize.
Differential Revision: https://reviews.llvm.org/D88573
D133866 added the llvm::isNeutralConstant helper to track neutral/passthrough constants
This patch updates foldSelectWithIdentityConstant to use the helper instead of maintaining its own opcode handling
Differential Revision: https://reviews.llvm.org/D134966
Using this helper makes work about neutral elements more easier. Although I only
find one case now, I think it will have more chance to be used since so many
combine works are related to neutral elements.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D133866
For gathers which load in 8 and 16 bit data then use that data
as an index, the index can be extended to 32 bits instead of
64 bits
Differential Revision: https://reviews.llvm.org/D130692
Add a new entry to SDNodeExtraInfo to propagate PCSections through
SelectionDAG.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D130882
During SelectionDAG legalization SDNodes with associated extra info may
be replaced with a new SDNode. Preserve associated extra info on
ReplaceAllUsesWith and remove entries in DeallocateNode.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D130881
For information infrequently attached to SDNodes, it is useful to
provide a way to add this information out-of-line. This is already done
for call-site specific information.
Rename CallSiteDbgInfo to NodeExtraInfo in preparation of adding
additional information not necessarily related to call sites only.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D130880
Similar to #57402 - we were calling isGuaranteedNotToBeUndefOrPoison on the freeze operand (with Depth = 0), but wasn't accounting for the fact that a later isGuaranteedNotToBeUndefOrPoison assertion will call from the new node (with Depth = 0 as well) - which will then recursively call isGuaranteedNotToBeUndefOrPoison for its operands with Depth = 1
Fixes#57554
This patch follows the InstCombine approach of stripping poison generating flags (nsw/nuw from add/sub etc.) to allow us to push a freeze() through the op. Unlike InstCombine it doesn't retain any flags, but we have plenty of DAG folds that do the same thing already. We assert that the newly generated op isGuaranteedNotToBeUndefOrPoison.
Similar to the ValueTracking approach, isGuaranteedNotToBeUndefOrPoison has been updated to confirm that if an op can't create undef/poison and its operands are guaranteed not to be undef/poison - then its not undef/poison. This is just for the generic opcodes - target specific opcodes will need to do this manually just in case they have some special cases.
Differential Revision: https://reviews.llvm.org/D132333
Extends findMoreOptimalIndexType to allow ISD::BUILD_VECTOR based
indices to be truncated when such truncation is lossless. This can
enable the use of 32bit gather/scatter indices thus making it less
likely to have to split a gather/scatter in two.
Depends on D125194
Differential Revision: https://reviews.llvm.org/D130533
These are guaranteed not to create undef/poison (although they may pass through) - the associated ISD::VALUETYPE node is also guaranteed never to generate poison
This patch makes the variants of `mm*_cast*` intel intrinsics that use `shufflevector(freeze(poison), ..)` emit efficient assembly.
(These intrinsics are planned to use `shufflevector(freeze(poison), ..)` after shufflevector's semantics update; relevant thread: D103874)
To do so, this patch
1. Updates `LowerAVXCONCAT_VECTORS` in X86ISelLowering.cpp to recognize `FREEZE(UNDEF)` operand of `CONCAT_VECTOR` in addition to `UNDEF`
2. Updates X86InstrVecCompiler.td to recognize `insert_subvector` of `FREEZE(UNDEF)` vector as its first operand.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D130339
This patch adds basic support for a DAG variant of the canCreateUndefOrPoison call and updates DAGCombiner::visitFREEZE to use it, further Opcodes (including target specific Opcodes) can be handled when we have test coverage.
So far, I've left visitFREEZE to just use this for unary nodes (which currently means the existing BITCAST/FREEZE cases) - later patches will add other unary opcodes (with test coverage) and we can also refactor visitFREEZE to support a general number of operands like we do in InstCombinerImpl::pushFreezeToPreventPoisonFromPropagating.
I'm not aware of any vector test freeze coverage so the DemandedElts (and the Depth) args are not being used yet - but they are in place. Similarly we will be able to handle poison generating SDNodeFlags as and when it becomes an issue.
Part of the work for D106675 / PR50468
Differential Revision: https://reviews.llvm.org/D130646
FoldConstantArithmetic can fold constant vectors hidden behind bitcasts (e.g. vXi64 -> v2Xi32 on 32-bit platforms), but currently bails if either vector contains undef elements. These undefs can often occur due to SimplifyDemandedBits/VectorElts calls recognising that the upper bits are often unnecessary (e.g. funnel-shift/rotate implicit-modulo and AND masks).
This patch adds a basic 'FoldValueWithUndef' handler that will attempt to constant fold if one or both of the ops are undef - so far this just handles the AND and MUL cases where we always fold to zero.
The RISCV codegen increase is interesting - it looks like the BUILD_VECTOR lowering was loading a constant pool entry but now (with all elements defined constant) it can materialize the constant instead?
Differential Revision: https://reviews.llvm.org/D130839
This patch ensures consistency in the construction of FP_ROUND nodes
such that they always use ISD::TargetConstant instead of ISD::Constant.
This additionally fixes a bug in the AArch64 SVE backend where patterns
were matching against TargetConstant nodes and sometimes failing when
passed a Constant node.
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D130370
Add a method for the various cases where we need to concatenate 2 KnownBits together (BUILD_PAIR and SHIFT_PARTS in particular) - uses the existing APInt::concat 'HiBits.concat(LoBits)' convention
Differential Revision: https://reviews.llvm.org/D130557
GetDemandedBits is mainly a wrapper around SimplifyMultipleUseDemandedBits now, and is only used by DAGCombiner::visitSTORE so I've moved all remaining functionality there.
visitSTORE was making use of this to 'simplify' constants for a trunc-store. Just removing this code left to a mixture of regressions and gains - it came down to whether a target preferred a sign or zero extended constant for materialization/truncation. I've just moved the code over for now, but a next step would be to move this to targetShrinkDemandedConstant, but some targets that override the method expect a basic binop, and might react badly to a store node.....
I'm actually trying to get rid of GetDemandedBits - but while dismantling it I noticed that we were altering opaque constants. Fixing that causes a FP_TO_INT_SAT regression that should be addressed separately - I'll raise a bug.
This patch allows SimplifyDemandedBits to call SimplifyMultipleUseDemandedBits in cases where the ISD::SRL source operand has other uses, enabling us to peek through the shifted value if we don't demand all the bits/elts.
This is another step towards removing SelectionDAG::GetDemandedBits and just using TargetLowering::SimplifyMultipleUseDemandedBits.
There a few cases where we end up with extra register moves which I think we can accept in exchange for the increased ILP.
Differential Revision: https://reviews.llvm.org/D77804
This patch starts small, only detecting sequences of the form
<a, a+n, a+2n, a+3n, ...> where a and n are ConstantSDNodes.
Differential Revision: https://reviews.llvm.org/D125194
We still haven't found a solution that correctly handles 'don't care' sub elements properly - given how close it is to the next release branch, I'm making this fail safe change and we can revisit this later if we can't find alternatives.
NOTE: This isn't a reversion of D128570 - it's the removal of undef handling across bitcasts entirely
Fixes#56520
