Rework getConstantstVRegValWithLookThrough in order to make it clear if we
are matching integer/float constant only or any constant(default).
Add helper functions that get DefVReg and APInt/APFloat from constant instr
getIConstantVRegValWithLookThrough: integer constant, only G_CONSTANT
getFConstantVRegValWithLookThrough: float constant, only G_FCONSTANT
getAnyConstantVRegValWithLookThrough: either G_CONSTANT or G_FCONSTANT
Rename getConstantVRegVal and getConstantVRegSExtVal to getIConstantVRegVal
and getIConstantVRegSExtVal. These now only match G_CONSTANT as described
in comment.
Relevant matchers now return both DefVReg and APInt/APFloat.
Replace existing uses of getConstantstVRegValWithLookThrough and
getConstantVRegVal with new helper functions. Any constant match is
only required in:
ConstantFoldBinOp: for constant argument that was bit-cast of float to int
getAArch64VectorSplat: AArch64::G_DUP operands can be any constant
amdgpu select for G_BUILD_VECTOR_TRUNC: operands can be any constant
In other places use integer only constant match.
Differential Revision: https://reviews.llvm.org/D104409
This also adds new interfaces for the fixed- and scalable case:
* LLT::fixed_vector
* LLT::scalable_vector
The strategy for migrating to the new interfaces was as follows:
* If the new LLT is a (modified) clone of another LLT, taking the
same number of elements, then use LLT::vector(OtherTy.getElementCount())
or if the number of elements is halfed/doubled, it uses .divideCoefficientBy(2)
or operator*. That is because there is no reason to specifically restrict
the types to 'fixed_vector'.
* If the algorithm works on the number of elements (as unsigned), then
just use fixed_vector. This will need to be fixed up in the future when
modifying the algorithm to also work for scalable vectors, and will need
then need additional tests to confirm the behaviour works the same for
scalable vectors.
* If the test used the '/*Scalable=*/true` flag of LLT::vector, then
this is replaced by LLT::scalable_vector.
Reviewed By: aemerson
Differential Revision: https://reviews.llvm.org/D104451
This is roughly equivalent to the floating point portion of
`AArch64TargetLowering::LowerVSETCC`. Main part that's missing is the v4s16 bit.
This also adds helpers equivalent to `EmitVectorComparison`, and
`changeVectorFPCCToAArch64CC`. This moves `changeFCMPPredToAArch64CC` out of
the selector into AArch64GlobalISelUtils for the sake of code reuse.
This is done in post-legalizer lowering with pseudos to simplify selection.
The imported patterns end up handling selection for us this way.
Differential Revision: https://reviews.llvm.org/D101782
This adds support for swapping comparison operands when it may introduce new
folding opportunities.
This is roughly the same as the code added to AArch64ISelLowering in
162435e7b5e026b9f988c730bb6527683f6aa853.
For an example of a testcase which exercises this, see
llvm/test/CodeGen/AArch64/swap-compare-operands.ll
(Godbolt for that testcase: https://godbolt.org/z/43WEMb)
The idea behind this is that sometimes, we may be able to fold away, say, a
shift or extend in a compare by swapping its operands.
e.g. in the case of this compare:
```
lsl x8, x0, #1
cmp x8, x1
cset w0, lt
```
The following is equivalent:
```
cmp x1, x0, lsl #1
cset w0, gt
```
Most of the code here is just a reimplementation of what already exists in
AArch64ISelLowering.
(See `getCmpOperandFoldingProfit` and `getAArch64Cmp` for the equivalent code.)
Note that most of the AND code in the testcase doesn't actually fold. It seems
like we're missing selection support for that sort of fold right now, since SDAG
happily folds these away (e.g testSwapCmpWithShiftedZeroExtend8_32 in the
original .ll testcase)
Differential Revision: https://reviews.llvm.org/D89422
For <2 x s32>, we can use G_DUPLANE32, but with a <4 x s32> source. To make it
work, we can just widen the original source with a concat_vectors.
Doing this allows <2 x float> indexed fmul instruction selection patterns to
fire, which gives a nice 0.3% code size saving on Bullet with -Os.
Differential Revision: https://reviews.llvm.org/D98059
If we have
```
%vec = G_BUILD_VECTOR %reg, %reg, ..., %reg
```
Then lower it to
```
%vec = G_DUP %reg
```
Also update the selector to handle constant splats on G_DUP.
This will not combine when the splat is all zeros or ones. Tablegen-imported
patterns rely on these being G_BUILD_VECTOR.
Minor code size improvements on CTMark at -Os.
Also adds some utility functions to make it a bit easier to recognize splats,
and an AArch64-specific splat helper.
Differential Revision: https://reviews.llvm.org/D97731
The order in which the nested calls to Builder.buildWhatever are
evaluated in differs between GCC and Clang.
This caused a bot failure because the MIR in the testcase was
coming out in a different order than expected.
Rather than using nested calls, pull them out in order to fix the
order of evaluation.
This reverts commit 867e379c0e14527eb7aa68485a10324693e35f5d.
For some reason this is upsetting Linux/Windows bots. Reverting while I try to
reproduce.
Match a G_SHUFFLE_VECTOR with a mask that allows it to be represented as a
G_INSERT_VECTOR_ELT and a G_EXTRACT_VECTOR_ELT.
This ports `isINSMask` from AArch64ISelLowering and the portion of
`AArch64TargetLowering::LowerVECTOR_SHUFFLE` which handles the equivalent
transformation.
This provides more opportunities for matching DUP. We don't have all of the
necessary combines to actually make DUP out of these yet, but this is better for
size than the full TBL expansion for G_SHUFFLE_VECTOR.
This is a -0.1% code size improvement on CTMark/Bullet at -Os.
IR example: https://godbolt.org/z/sdcevT
Differential Revision: https://reviews.llvm.org/D97214
Returning int64_t was arbitrarily limiting for wide integer types, and
the functions should handle the full generality of the IR.
Also changes the full form which returns the originally defined
vreg. Add another wrapper for the common case of just immediately
converting to int64_t (arguably this would be useful for the full
return value case as well).
One possible issue with this change is some of the existing uses did
break without conversion to getConstantVRegSExtVal, and it's possible
some without adequate test coverage are now broken.
It's fairly common to need matchers for a specific constant value, or for
common idioms like finding a negated register.
Add
- `m_SpecificICst`, which returns true when matching a specific value..
- `m_ZeroInt`, which returns true when an integer 0 is matched.
- `m_Neg`, which returns when a register is negated.
Also update a few places which use idioms related to the new matchers.
Differential Revision: https://reviews.llvm.org/D91397
These were previously handled by pattern matching shuffles in the selector, but
adding a new opcode and making it equivalent to the AArch64duplane SDAG node
allows us to select more patterns, like lane indexed FMLAs (patch adding a test
for that will be committed later).
The pattern matching code has been simply moved to postlegalize lowering.
Differential Revision: https://reviews.llvm.org/D90820
Move the code which adjusts the immediate/predicate on a G_ICMP to
AArch64PostLegalizerLowering.
This
- Reduces the number of places we need to test for optimized compares in the
selector. We know that the compare should have been simplified by the time it
hits the selector, so we can avoid testing this in selects, brconds, etc.
- Allows us to potentially fold more compares (previously, this optimization
was only done after calling `tryFoldCompare`, this may allow us to hit some more
TST cases)
- Simplifies the selection code in `emitIntegerCompare` significantly; we can
just use an emitSUBS function.
- Allows us to avoid checking that the predicate has been updated after
`emitIntegerCompare`.
Also add a utility header file for things that may be useful in the selector
and various combiners. No need for an implementation file at this point, since
it's just one constexpr function for now. I've run into a couple cases where
having one of these would be handy, so might as well add it here. There are
a couple functions in the selector that can probably be factored out into
here.
Differential Revision: https://reviews.llvm.org/D89823
There are a lot of combines in AArch64PostLegalizerCombiner which exist to
facilitate instruction matching in the selector. (E.g. matching for G_ZIP and
other shuffle vector pseudos)
It still makes sense to select these instructions at -O0.
Matching earlier in a combiner can reduce complexity in the selector
significantly. For example, a good portion of our selection code for compares
would be a lot easier to represent in a combine.
This patch moves matching combines into a "AArch64PostLegalizerLowering"
combiner which runs at all optimization levels.
Also, while we're here, improve the documentation for the
AArch64PostLegalizerCombiner, and fix up the filepath in its file comment.
And also add a 'r' which somehow got dropped from a bunch of function names.
https://reviews.llvm.org/D89820
