When shifting by a byte-multiple:
bswap (shl X, C) --> lshr (bswap X), C
bswap (lshr X, C) --> shl (bswap X), C
This is the backend version of D122010 and an alternative
suggested in D120648.
There's an extra check to make sure the shift amount is
valid that was not in the rough draft.
I'm not sure if there is a larger motivating case for RISCV (bug report?),
but the ARM diffs show a benefit from having a late version of the
transform (because we do not combine the loads in IR).
Differential Revision: https://reviews.llvm.org/D122655
On targets which don't allow "@" in unquoted identifiers, make sure we
don't emit them; otherwise, we can't parse our own output.
Differential Revision: https://reviews.llvm.org/D122516
D113200 introduced an error where it was converting FP_TO_SI_SAT with
multiply to a fixed point floating point convert. The saturation
bitwidth needs to be equal to the floating point width, or else the
routine would truncate the result as opposed to saturating it.
Fixes#54601
Accord the discussion in D120953, we should firstly exclude all scalable vector
extending loads and then selectively enable those which we directly support.
This patch is intend to refactor for above (truncating stores is not touched),and
more scalable vector types will try to reduce the number of masked loads in favour
of more unpklo/hi instructions.
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D122281
The default expansion for buildvectors is to extract each element and
insert them into a new vector. That involves a lot of copying to/from
the GPR registers. TLB3 and TLB4 can be relatively slow instructions
with the mask needing to be loaded from a constant pool, but they should
always be better than all the moves to/from GPRs.
Differential Revision: https://reviews.llvm.org/D121137
Now, perform last active true vector combine only where
we're extracting from a flag-setting operation. But in
fact, the last active extracting will output LASTB + WHILELS,
and the WHILELS itself is a flag-setting operation, so
precommit this case to test the potentially further optimization.
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D122453
Re-commit of 32e8b550e5439c7e4aafa73894faffd5f25d0d05
This patch rearranges emission of CFI instructions, so the resulting
DWARF and `.eh_frame` information is precise at every instruction.
The current state is that the unwind info is emitted only after the
function prologue. This is fine for synchronous (e.g. C++) exceptions,
but the information is generally incorrect when the program counter is
at an instruction in the prologue or the epilogue, for example:
```
stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
mov x29, sp
.cfi_def_cfa w29, 16
...
```
after the `stp` is executed the (initial) rule for the CFA still says
the CFA is in the `sp`, even though it's already offset by 16 bytes
A correct unwind info could look like:
```
stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
.cfi_def_cfa_offset 16
mov x29, sp
.cfi_def_cfa w29, 16
...
```
Having this information precise up to an instruction is useful for
sampling profilers that would like to get a stack backtrace. The end
goal (towards this patch is just a step) is to have fully working
`-fasynchronous-unwind-tables`.
Reviewed By: danielkiss, MaskRay
Differential Revision: https://reviews.llvm.org/D111411
The default expansion for buildvectors is to extract each element and
insert them into a new vector. That involves a lot of copying to/from
the GPR registers. TLB3 and TLB4 can be relatively slow instructions
with the mask needing to be loaded from a constant pool, but they should
always be better than all the moves to/from GPRs.
Differential Revision: https://reviews.llvm.org/D121137
This reverts commit edb7ba714acba1d18a20d9f4986d2e38aee1d109.
This changes BLR_BTI to take variable_ops meaning that we can accept
a register or a label. The pattern still expects one argument so we'll
never get more than one. Then later we can check the type of the operand
to choose BL or BLR to emit.
(this is what BLR_RVMARKER does but I missed this detail of it first time around)
Also require NoSLSBLRMitigation which I missed in the first version.
Some implementations of setjmp will end with a br instead of a ret.
This means that the next instruction after a call to setjmp must be
a "bti j" (j for jump) to make this work when branch target identification
is enabled.
The BTI extension was added in armv8.5-a but the bti instruction is in the
hint space. This means we can emit it for any architecture version as long
as branch target enforcement flags are passed.
The starting point for the hint number is 32 then call adds 2, jump adds 4.
Hence "hint #36" for a "bti j" (and "hint #34" for the "bti c" you see
at the start of functions).
The existing Arm command line option -mno-bti-at-return-twice has been
applied to AArch64 as well.
Support is added to SelectionDAG Isel and GlobalIsel. FastIsel will
defer to SelectionDAG.
Based on the change done for M profile Arm in https://reviews.llvm.org/D112427Fixes#48888
Reviewed By: danielkiss
Differential Revision: https://reviews.llvm.org/D121707
Trying to reduce the number of masked loads in favour of more unpklo/hi
instructions. Both ISD::ZEXTLOAD and ISD::SEXTLOAD are supported to extensions
from legal types.
Both of normal and masked loads test cases added to guard compile crash.
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D120953
When N > 12, (2^N -1) is not a legal add immediate (isLegalAddImmediate will return false).
ANd if SetCC input use this number, DAG combiner will generate one more SRL instruction.
So combine [setcc (srl x, imm), 0, ne] to [setcc (and x, (-1 << imm)), 0, ne] to get better optimization in emitComparison
Fix https://github.com/llvm/llvm-project/issues/54283
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D121449
When inverting the compare predicate trySwapVSelectOperands is
incorrectly using the type of the select's cond operand rather
than the type of cond's operands. This means we're treating all
inversions as if they're integer.
Differential Revision: https://reviews.llvm.org/D121968
We already have custom lowering for v4i8 load, which loads as a f32,
converts to a vector and bitcasts and extends the result to a v4i16.
This adds some custom lowering of concat(v4i8 load, ...) to keep the
result as an f32 and create a buildvector of the resulting f32 loads.
This helps not create all the extends and bitcasts, which are often
difficult to fully clean up.
Differential Revision: https://reviews.llvm.org/D121400
If we already have a AArch64ISD::ANDS node with identical operands, we
can merge any ISD::AND into it, reducing the instruction count by
calculating the value and the flags in a single operation. This code is
taken from the X86 backend, and could also handle AArch64ISD::ADDS and
AArch64ISD::SUBS, but I couldn't find any test cases where it came up.
Differential Revision: https://reviews.llvm.org/D118584
The existing volatile checks only handle aliasing hazards between stores,
but that isn't enough since by that point volatile stores may have already
been added to the current candidate group.
Discussed extensively on D98232. The functionality introduced in D35816
never worked correctly. In D98232, it was fixed, but, as it was
introducing a large compile-time regression, and the value of the
original patch was called into doubt, we disabled it by default
everywhere. A year later, it appears that caused no grief, so it seems
safe to remove the disabled code.
This should be accompanied by re-opening bug 26810.
Differential Revision: https://reviews.llvm.org/D121128
Includes verifier changes checking the elementtype, clang codegen
changes to emit the elementtype, and ISel changes using the elementtype.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D120527
We do not have general reassociation here (and probably
do not need it), but I noticed these were missing in
patches/tests motivated by D111530, so we can at
least handle the simplest patterns.
The VE test diff looks correct, but we miss that
pattern in IR currently:
https://alive2.llvm.org/ce/z/u66_PM
When building the LLVM test suite with SVE I discovered a crash
when compiling some Halide tests, which occurs because we try to
use SVE to lower 64-bit vector multiplies and there is no
vscale_range attribute on the function. In this case the min SVE
vector bits was 0, which caused an assert in LowerToPredicatedOp
to fire. I have amended the asserts in this function to check that the
fixed-width type is legal. If the fixed-width type is larger than NEON
and is legal then it must be because we've set the min SVE vector
bits to something > 128. Or if the min SVE bits is 0, then the only
legal types allowed are 128 bit types - for any other types the assert
will fire.
Tests added here:
CodeGen/AArch64/sve-fixed-length-no-vscale-range.ll
Differential Revision: https://reviews.llvm.org/D121297
While checking is tail call optimization is possible, the calling
convention applied to fixed arguments is not the correct one.
This implies for DarwinPCS that all arguments of a vararg function will
go to the stack although fixed ones can go in registers.
This prevents non-virtual thunks to be tail optimized although they are
marked as musttail.
Differential Revision: https://reviews.llvm.org/D120622
A TBL instruction will use zero for any out of range values. We can use
this in GenerateTBL to help turn a TBL2 into a TBL1, avoiding the need
to materialise the zero.
Differential Revision: https://reviews.llvm.org/D121139
The prologue and epilogue emission were unbalanced in light of different
strategies of async frame context emission. Adjust the epilogue emission
to match the prologue emission. This makes the elision work properly as
well as the deployment based. Due to the fact that the epilogue always
was clearing a bit (which should not be set in the first place), the
client would not notice the behavioural issue unless the deployment
version was in effect.
This is another fold generalized from D111530.
We can find a common source for a rotate operation hidden inside an 'or':
https://alive2.llvm.org/ce/z/9pV8hn
Deciding when this is profitable vs. a funnel-shift is tricky, but this
does not show any regressions: if a target has a rotate but it does not
have a funnel-shift, then try to form the rotate here. That is why we
don't have x86 test diffs for the scalar tests that are duplicated from
AArch64 ( 74a65e3834d9487 ) - shld/shrd are available. That also makes it
difficult to show vector diffs - the only case where I found a diff was
on x86 AVX512 or XOP with i64 elements.
There's an additional check for a legal type to avoid a problem seen
with x86-32 where we form a 64-bit rotate but then it gets split
inefficiently. We might avoid that by adding more rotate folds, but
I didn't check to see what is missing on that path.
This gets most of the motivating patterns for AArch64 / ARM that are in
D111530.
We still need a couple of enhancements to setcc pattern matching with
rotate/funnel-shift to get the rest.
Differential Revision: https://reviews.llvm.org/D120933
Materialize : i1 = extract_vector_elt t37, Constant:i64<0>
... into: "ptrue p, all" + PTEST
Test bit of lane 0 can use P register directly, and the instruction “pture all”
is loop invariant, which will beneficial to SVE after hoisting out the loop.
Reviewed By: david-arm, paulwalker-arm
Differential Revision: https://reviews.llvm.org/D120891
When lowering large v16f32->v16i8 fp_to_si_sat, the fp_to_si_sat node is
split several times, creating an illegal v4i8 concat that gets expanded
into a BUILD_VECTOR. After some combining and other legalisation, it
ends up the a buildvector that extracts from 4 vectors, looking like
BUILDVECTOR(a0,a1,a2,a3,b0,b1,b2,b3,c0,c1,c2,c3,d0,d1,d2,d3). That is
really an v16i32->v16i8 truncate in disguise.
This adds a ReconstructTruncateFromBuildVector method to detect the
pattern, converting it back into the legal "concat(trunc(concat(trunc(a),
trunc(b))), trunc(concat(trunc(c), trunc(d))))" tree. The extracted
nodes could also be v4i16, in which case the truncates are not needed.
All those truncates and concats then become uzip1's, which is much
better than expanding by moving vector lanes around.
Differential Revision: https://reviews.llvm.org/D119469
When inserting undef into buildvectors created from shuffles of
buildvectors, we convert elements to the largest needed type. This had
the effect of converting undef into 0, which isn't needed as the
buildvector implicitly truncates and trunc(zext(undef)) == undef.
Differential Revision: https://reviews.llvm.org/D121002
This extends acb96ffd149d to 'and' and 'xor' opcodes.
Copying from that message:
LOGIC (LOGIC (SH X0, Y), Z), (SH X1, Y) --> LOGIC (SH (LOGIC X0, X1), Y), Z
https://alive2.llvm.org/ce/z/QmR9rR
This is a reassociation + factoring fold. The common shift operation is moved
after a bitwise logic op on 2 input operands.
We get simpler cases of these patterns in IR, but I suspect we would miss all
of these exact tests in IR too. We also handle the simpler form of this plus
several other folds in DAGCombiner::hoistLogicOpWithSameOpcodeHands().
It caused builds to assert with:
(StackSize == 0 && "We already have the CFA offset!"),
function generateCompactUnwindEncoding, file AArch64AsmBackend.cpp, line 624.
when targeting iOS. See comment on the code review for reproducer.
> This patch rearranges emission of CFI instructions, so the resulting
> DWARF and `.eh_frame` information is precise at every instruction.
>
> The current state is that the unwind info is emitted only after the
> function prologue. This is fine for synchronous (e.g. C++) exceptions,
> but the information is generally incorrect when the program counter is
> at an instruction in the prologue or the epilogue, for example:
>
> ```
> stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
> mov x29, sp
> .cfi_def_cfa w29, 16
> ...
> ```
>
> after the `stp` is executed the (initial) rule for the CFA still says
> the CFA is in the `sp`, even though it's already offset by 16 bytes
>
> A correct unwind info could look like:
> ```
> stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
> .cfi_def_cfa_offset 16
> mov x29, sp
> .cfi_def_cfa w29, 16
> ...
> ```
>
> Having this information precise up to an instruction is useful for
> sampling profilers that would like to get a stack backtrace. The end
> goal (towards this patch is just a step) is to have fully working
> `-fasynchronous-unwind-tables`.
>
> Reviewed By: danielkiss, MaskRay
>
> Differential Revision: https://reviews.llvm.org/D111411
This reverts commit 32e8b550e5439c7e4aafa73894faffd5f25d0d05.
