After changes, that does not require support from InstCombine, we can
drop some extra requirements for values-to-be-demoted. No need to check
for external uses for roots/other instructions, just check that the
no non-vectorized insertelement instruction, which may require
widening.
SLP vectorizer passes the type of the subvector and the mask, which size
determines the size of the resulting vector. TTI should support this
pattern to improve cost estimation of the insert_subvector shuffle
pattern.
Need to limit the transformation of the VecMask by the corresponding part of the mask of SliceSize size to avoid compiler crash during further cost analysis.
vectorized.
When trying to reuse the extractelement instruction, emitted for the
insertelement instruction, need to check, if the this insertelement
instruction was vectorized. In this case, need to use vectorized value,
not the original insertelement.
vectorized.
If the insertelement instruction is vectorized, and the extractelement
instruction from such insertelement also vectorized as part of the same
tree, need to extract from the corresponding for insertelement vectorized value rather than original insertelement instruction.
llvm/lib/IR/Type.cpp:694:
Assertion `isValidElementType(ElementType) && "Element type of a
VectorType must be an integer, floating point, or pointer type."'
failed.
Stack dump:
llvm::FixedVectorType::get(llvm::Type*, unsigned int)
llvm::VPWidenCallRecipe::execute(llvm::VPTransformState&)
llvm::VPBasicBlock::execute(llvm::VPTransformState*)
llvm::VPRegionBlock::execute(llvm::VPTransformState*)
llvm::VPlan::execute(llvm::VPTransformState*)
...
Happens with function calls of void return type.
SLP/TTI do not know about the cost estimation for addsub pattern,
supported by X86. Previously the support for pattern detection was added
(seeTTI::isLegalAltInstr), but the cost still did not estimated
properly.
SLP/TTI do not know about the cost estimation for addsub pattern,
supported by X86. Previously the support for pattern detection was added
(seeTTI::isLegalAltInstr), but the cost still did not estimated
properly.
If decided to resize the instruction, need to drop wrapping flags from
the resulting vector instructions to avoid incorrect
optimizations/assumptions later.
Fixes PR75995.
Issue is covered by existing test
llvm/test/Transforms/SLPVectorizer/RISCV/phi-const.ll
See issue #75632 for ideas for how we could catch these more easily in
the future.
SLP Vectorizer can discard vector entries at unknown positions. This
example shows the behaviour:
https://godbolt.org/z/or43EM594
The following instruction inserts an element at an unknown position:
```
%2 = insertelement <3 x i64> poison, i64 %value, i64 %position
```
The position depends on an argument that is unknown at compile time.
After running SLP, one can see there is no more instruction present
referencing `%position`.
This happens as SLP parallelizes the two adds in the example. It then
needs to merge the original vector with the new vector.
Within `isUndefVector`, the SLP vectorizer constructs a bitmap
indicating which elements of the original vector are poison values. It
does this by walking the insertElement instructions.
If it encounters an insert with a non-constant position, it is ignored.
This will result in poison values to be used for all entries, where
there are no inserts with constant positions.
However, as the position is unknown, the element could be anywhere.
Therefore, I think it is only safe to assume none of the entries are
poison values and to simply take them all over when constructing the
shuffleVector instruction.
This fixes#75437
nodes, having same last instruction.
If the user nodes has the same last-instruction, used as insert points
for the buildvector nodes, finding the proper dependency is crucial.
Before, it depended on the indices of the buildvectors themselves but
looks like it should depend on indices of the user nodes, because it
identifies the vectorization order and, thus, properly aligns
buildvector nodes in terms of def-use chain.
Minor simplification applied to VFShape::getScalarShape,
VFShape::get, and VFABI::tryDemangleForVFABI methods.
Also, remove unnecessary `static_cast` in `SLPVectorizer.cpp`
Currently we emit gathers for scalars being vectorized in the tree as
a pair of extractelement/insertelement instructions. Instead we can try
to find all required vectors and emit shuffle vector instructions
directly, improving the code and reducing compile time.
Part of non-power-of-2 vectorization.
Differential Revision: https://reviews.llvm.org/D110978
Currently, MinBWs map uses Value* as a key and stores mapping for each
value to be demoted. It make is it hard to get the actual MinBWs value
for the buildvector scalars(constants), since same constant might be
used in different nodes with the different MinBWs values/decisions.
Also, it consumes extra memory for the vectorized values/instructions
from the same nodes.
Better to map actual nodes. It fixes the bitwidth data fetching for
buildvector scalars and improves memory consumption/analysis time for
other instructions.
No need to store optional boolean in the map, enough to store boolean
directly. Also, we can do preliminary check for instruction and if they
are not simple, mark as aliased without storing this result in the map.
If the gather node includes ordered loads only partially (not the whole
node consists of loads) and the other gathered scalar are not loads, and
no other dependency from other nodes is found, we still can improve the
cost of gather, if take into account the fact that these loads still can
be vectorized.
operand.
Need to copy the submask not to the very first part of the common
extractelements vector mask, but to the proper one to avoid wrong code
emission.
