Refines the gather/scatter cost model, but also changes the TTI
function getIntrinsicInstrCost to accept an additional parameter
which is needed for the gather/scatter cost evaluation.
This did require trivial changes in some non-ARM backends to
adopt the new parameter.
Extending gathers and truncating scatters are now priced cheaper.
Differential Revision: https://reviews.llvm.org/D75525
Summary:
Instead of generating two i32 instructions for each load or store of a volatile
i64 value (two LDRs or STRs), now emit LDRD/STRD.
These improvements cover architectures implementing ARMv5TE or Thumb-2.
The code generation explicitly deviates from using the register-offset
variant of LDRD/STRD. In this variant, the register allocated to the
register-offset cannot be reused in any of the remaining operands. Such
restriction seems to be non-trivial to implement in LLVM, thus it is
left as a to-do.
Reviewers: dmgreen, efriedma, john.brawn, nickdesaulniers
Reviewed By: efriedma, nickdesaulniers
Subscribers: danielkiss, alanphipps, hans, nathanchance, nickdesaulniers, vvereschaka, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70072
On some Arm cores there is a performance penalty when forwarding from an
S register to a D register. Calculating VMAX in a D register creates
false forwarding hazards, so don't do that unless we're on a core which
specifically asks for it.
Patch by James Greenhalgh
Differential Revision: https://reviews.llvm.org/D75248
Iterate through the loop and check that the observable values
produced are the same whether tail predication happens or not.
We want to find out if the tail-predicated version of this loop will
produce the same values as the loop in its original form. For this to
be true, the newly inserted implicit predication must not change the
the (observable) results.
We're doing this because many instructions in the loop will not be
predicated and so the conversion from VPT predication to tail
predication can result in different values being produced, because of
falsely predicated lanes not being updated in the converted form.
A masked load, whether through VPT or tail predication, will write
zeros to any of the falsely predicated bytes. So, from the loads, we
know that the false lanes are zeroed and here we're trying to track
that those false lanes remain zero, or where they change, the
differences are masked away by their user(s).
All MVE loads and stores have to be predicated, so we know that any
load operands, or stored results are equivalent already. Other
explicitly predicated instructions will perform the same operation in
the original loop and the tail-predicated form too. Because of this,
we can insert loads, stores and other predicated instructions into
our KnownFalseZeros set and build from there.
Differential Revision: https://reviews.llvm.org/D75452
Summary:
ARMAsmParser was incorrectly dropping a leading dollar sign character
from symbol names in targets of branch instructions. This was caused by
an incorrect assumption that the contents following the dollar sign
token should be handled as a constant immediate, similarly to the #
token.
This patch avoids the operand parsing from consuming the dollar sign
token when it is followed by an identifier, making sure it is properly
parsed as part of the expression.
Reviewers: efriedma
Reviewed By: efriedma
Subscribers: danielkiss, chill, carwil, vhscampos, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73176
Summary:
The VSHLC instruction performs a left shift of a whole vector register
by an immediate shift count up to 32, shifting in new bits at the low
end from a GPR and delivering the shifted-out bits from the high end
back into the same GPR.
Since the instruction produces two outputs (the shifted vector
register and the output GPR of shifted-out bits), it has to be
instruction-selected in C++ rather than Tablegen.
Reviewers: MarkMurrayARM, dmgreen, miyuki, ostannard
Reviewed By: miyuki
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D75445
Summary:
These are exactly parallel to the existing `vadciq` intrinsics, which
we implemented last year as part of the original MVE intrinsics
framework setup.
Just like VADC/VADCI, the MVE VSBC/VSBCI instructions deliver two
outputs, both of which the intrinsic exposes: a modified vector
register and a carry flag. So they have to be instruction-selected in
C++ rather than Tablegen. However, in this case, that's trivial: the
same C++ isel routine we already have for VADC works unchanged, and
all we have to do is to pass it a different instruction id.
Reviewers: MarkMurrayARM, dmgreen, miyuki, ostannard
Reviewed By: miyuki
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D75444
Use MIOperand in collectLocalKilledOperands to make the search
global, as we already have to search for global uses too. This
allows us to delete more dead code when tail predicating.
Differential Revision: https://reviews.llvm.org/D75167
In RDA, check against the already decided dead instructions when
looking at users. This allows an instruction to be removed if it
has multiple users, but they're all dead.
This means that IT instructions can be considered killed once all
the itstate using instructions are dead.
Differential Revision: https://reviews.llvm.org/D75245
Summary:
It is not safe for ARMConstantIslands to undoLRSpillRestore. PrologEpilogInserter is
the one to ensure stack alignment, taking into consideration LR is spilled or not.
For noreturn function with StackAlignment 8 (function contains call/alloc),
undoLRSpillRestore cause stack be mis-aligned. Fixing stack alignment in
ARMConstantIslands doesn't give us much benefit, as undo LR spill/restore only
occur in large function with near branches only, also doesn't have callee-saved LR spill.
Reviewers: t.p.northover, rengolin, efriedma, apazos, samparker, ostannard
Reviewed By: ostannard
Subscribers: dmgreen, ostannard, kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75288
This patch upstreams support for the ARM Armv8.1m cpu Cortex-M55.
In detail adding support for:
- mcpu option in clang
- Arm Target Features in clang
- llvm Arm TargetParser definitions
details of the CPU can be found here:
https://developer.arm.com/ip-products/processors/cortex-m/cortex-m55
Reviewers: chill
Reviewed By: chill
Subscribers: dmgreen, kristof.beyls, hiraditya, cfe-commits,
llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D74966
Summary:
These instructions convert a vector of floats to a vector of integers
of the same size, with assorted non-default rounding modes.
Implemented in IR as target-specific intrinsics, because as far as I
can see there are no matches for that functionality in the standard IR
intrinsics list.
Reviewers: MarkMurrayARM, dmgreen, miyuki, ostannard
Reviewed By: dmgreen
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D75255
Summary:
These instructions make a vector of `<4 x float>` by widening every
other lane of a vector of `<8 x half>`.
I wondered about representing these using standard IR, along the lines
of a shufflevector to extract elements of the input into a `<4 x half>`
followed by an `fpext` to turn that into `<4 x float>`. But it looks as
if that would take a lot of work in isel lowering to make it match any
pattern I could sensibly write in Tablegen, and also I haven't been
able to think of any other case where that pattern might be generated
in IR, so there wouldn't be any extra code generation win from doing
it that way.
Therefore, I've just used another target-specific intrinsic. We can
always change it to the other way later if anyone thinks of a good
reason.
(In order to put the intrinsic definition near similar things in
`IntrinsicsARM.td`, I've also lifted the definition of the
`MVEMXPredicated` multiclass higher up the file, without changing it.)
Reviewers: MarkMurrayARM, dmgreen, miyuki, ostannard
Reviewed By: miyuki
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D75254
Summary:
The two MVE instructions that convert between v4f32 and v8f16 were
implemented as instances of the same class, with the same MC operand
list.
But that's not really appropriate, because the narrowing conversion
only partially overwrites its output register (it only has 4 f16
values to write into a vector of 8), so even when unpredicated, it
needs a $Qd_src input, a constraint tying that to the $Qd output, and
a vpred_n.
The widening conversion is better represented like any other
instruction that completely replaces its output when unpredicated: it
should have no $Qd_src operand, and instead, a vpred_r containing a
$inactive parameter. That's a better match to other similar
instructions, such as its integer analogue, the VMOVL instruction that
makes a v4i32 by sign- or zero-extending every other lane of a v8i16.
This commit brings the widening VCVT.F32.F16 into line with the other
instructions that behave like it. That means you can write isel
patterns that use it unpredicated, without having to add a pointless
undefined $QdSrc operand.
No existing code generation uses that instruction yet, so there should
be no functional change from this fix.
Reviewers: MarkMurrayARM, dmgreen, miyuki, ostannard
Reviewed By: dmgreen
Subscribers: kristof.beyls, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75253
Summary:
These instructions work like VMOVN (narrowing a vector of wide values
to half size, and overwriting every other lane of an output register
with the result), except that the narrowing conversion is saturating.
They come in three signedness flavours: signed to signed, unsigned to
unsigned, and signed to unsigned. All are represented in IR by a
target-specific intrinsic that takes two separate 'unsigned' flags.
Reviewers: MarkMurrayARM, dmgreen, miyuki, ostannard
Reviewed By: dmgreen
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D75252
The MVE gather instructions smaller than 32bits zext extend the values
in the offset register, as opposed to sign extending them. We need to
make sure that the code that we select from is suitably extended, which
this patch attempts to fix by tightening up the offset checks.
Differential Revision: https://reviews.llvm.org/D75361
As a narrow stopgap for the assertion failure described in PR45025, add
a describeLoadedValue override to ARMBaseInstrInfo and use it to detect
copies in which the forwarding reg is a super/sub reg of the copy
destination. For the moment this is unsupported.
Several follow ups are possible:
1) Handle VORRq. At the moment, we do not, because isCopyInstrImpl
returns early when !MI.isMoveReg().
2) In the case where forwarding reg is a super-reg of the copy
destination, we should be able to describe the forwarding reg as a
subreg within the copy destination. I'm not 100% sure about this, but
it looks like that's what's done in AArch64InstrInfo.
3) In the case where the forwarding reg is a sub-reg of the copy
destination, maybe we could describe the forwarding reg using the
copy destinaion and a DW_OP_LLVM_fragment (I guess this should be
possible after D75036).
https://bugs.llvm.org/show_bug.cgi?id=45025
rdar://59772698
Differential Revision: https://reviews.llvm.org/D75273
This addes extra patterns for the VMLAS MVE instruction, which performs
Qda = Qda * Qn + Rm, a similar pattern to the existing VMLA. The sinking
of splat(Rm) into the loop is already performed, meaning we just need
extra Pat's in tablegen.
Differential Revision: https://reviews.llvm.org/D75115
Add ELF relocations for the following fixups:
fixup_thumb_adr_pcrel_10 -> R_ARM_THM_PC8
fixup_thumb_cp -> R_ARM_THM_PC8
fixup_t2_adr_pcrel_12 -> R_ARM_THM_PREL_11_0
fixup_t2_ldst_pcrel_12 -> R_ARM_THM_PC12
While these relocations are short-ranged there is support in the open
source ELF linker's in binutils and soon to be in LLD. MC will no longer
resolve pc-relative fixups to global symbols due to interpositioning
concerns. We can handle these at link time by implementing the relocations.
The R_ARM_THM_PC8 has some extra encoding rules for addends that llvm-mc
sidesteps by not supporting addends for these instructions, using the wide
Thumb 2 instruction if it is available. I think that this is a reasonable
compromise given that these are rare.
This partiall reverts D72892, the Thumb fixups no longer need to be
evaluated at assembly time.
Differential Revision: https://reviews.llvm.org/D75039
Ensure that we're recording implicit defs, as well as visiting implicit
uses and implicit defs when we're walking through operands.
Differential Revision: https://reviews.llvm.org/D75185
Support the explicit wide assembler qualifier for the dmb/dsb/isb synchronization barrier instructions.
Differential revision: https://reviews.llvm.org/D75143
Under fp16 we optimise the bitcast between a VMOVhr and a CopyToReg via
custom lowering. This rewrites that to be a DAG combine instead, which
helps produce better code in the cases where the bitcast is actaully
legal.
Differential Revision: https://reviews.llvm.org/D72753
MC currently does not emit these relocation types, and lld does not
handle them. Add FKF_Constant as a work-around of some ARM code after
D72197. Eventually we probably should implement these relocation types.
By Fangrui Song!
Differential revision: https://reviews.llvm.org/D72892
Summary:
This commit adds the predicated MVE intrinsics for the same set of
unary operations that I added in their unpredicated forms in
* D74333 (vrint)
* D74334 (vrev)
* D74335 (vclz, vcls)
* D74336 (vmovl)
* D74337 (vmovn)
but since the predicated versions are a lot more similar to each
other, I've kept them all together in a single big patch. Everything
here is done in the standard way we've been doing other predicated
operations: an IR intrinsic called `@llvm.arm.mve.foo.predicated` and
some isel rules that match that alongside whatever they accept for the
unpredicated version of the same instruction.
In order to write the isel rules conveniently, I've refactored the
existing isel rules for the affected instructions into multiclasses
parametrised by a vector-type class, in the usual way. All those
refactorings are intended to leave the existing isel rules unchanged:
the only difference should be that new ones for the predicated
intrinsics are introduced.
The only tiny infrastructure change I needed in this commit was to
change the implementation of `IntrinsicMX` in `arm_mve_defs.td` so
that the records it defines are anonymous rather than named (and use
`NameOverride` to set the output intrinsic name), which allows me to
call it twice in two multiclasses with the same `NAME` without a
tablegen-time error.
Reviewers: dmgreen, MarkMurrayARM, miyuki, ostannard
Reviewed By: MarkMurrayARM
Subscribers: kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D75165
Add getUniqueReachingMIDef to RDA which performs a global search for
a machine instruction that produces a unique definition of a given
register at a given point. Also add two helper functions
(getMIOperand) that wrap around this functionality to get the
incoming definition uses of a given instruction. These now replace
the uses of getReachingMIDef in ARMLowOverheadLoops. getReachingMIDef
has been renamed to getReachingLocalMIDef and has been made private
along with getInstFromId.
Differential Revision: https://reviews.llvm.org/D74605
Fixed an issue exposed by D74006.
In clang cc1as, MCContext::UseNamesOnTempLabels is true.
When parsing a .fnstart directive, FnStart gets redefined to a temporary symbol of a different name (.Ltmp0, .Ltmp1, ...).
MCContext::getELFSection() called by SwitchToEHSection() will create a different .ARM.exidx each time.
llvm-mc uses `Ctx.setUseNamesOnTempLabels(false);` and FnStart is unnamed.
MCContext::getELFSection() called by SwitchToEHSection() will reuse the same .ARM.exidx .
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D75095
This node reads the rounding control which means it needs to be ordered properly with operations that change the rounding control. So it needs to be chained to maintain order.
This patch adds a chain input and output to the node and connects it to the chain in SelectionDAGBuilder. I've update all in-tree targets to connect their chain through their lowering code.
Differential Revision: https://reviews.llvm.org/D75132
Summary:
Future patches will make use of TTI to perform cost-model-driven `SCEVExpander::isHighCostExpansionHelper()`
This is a fully NFC patch to make things reviewable.
Reviewers: reames, mkazantsev, wmi, sanjoy
Reviewed By: mkazantsev
Subscribers: hiraditya, zzheng, javed.absar, dmgreen, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D73704
This adds infrastructure to print and parse MIR MachineOperand comments.
The motivation for the ARM backend is to print condition code names instead of
magic constants that are difficult to read (for human beings). For example,
instead of this:
dead renamable $r2, $cpsr = tEOR killed renamable $r2, renamable $r1, 14, $noreg
t2Bcc %bb.4, 0, killed $cpsr
we now print this:
dead renamable $r2, $cpsr = tEOR killed renamable $r2, renamable $r1, 14 /* CC::always */, $noreg
t2Bcc %bb.4, 0 /* CC:eq */, killed $cpsr
This shows that MachineOperand comments are enclosed between /* and */. In this
example, the EOR instruction is not conditionally executed (i.e. it is "always
executed"), which is encoded by the 14 immediate machine operand. Thus, now
this machine operand has /* CC::always */ as a comment. The 0 on the next
conditional branch instruction represents the equal condition code, thus now
this operand has /* CC:eq */ as a comment.
As it is a comment, the MI lexer/parser completely ignores it. The benefit is
that this keeps the change in the lexer extremely minimal and no target
specific parsing needs to be done. The changes on the MIPrinter side are also
minimal, as there is only one target hooks that is used to create the machine
operand comments.
Differential Revision: https://reviews.llvm.org/D74306
Change the way that we remove the redundant iteration count code in
the presence of IT blocks. collectLocalKilledOperands has been
introduced to scan an instructions operands, collecting the killed
instructions and then visiting them too. This is used to delete the
code in the preheader which calculates the iteration count. We also
track any IT blocks within the preheader and, if we remove all the
instructions from the IT block, we also remove the IT instruction.
isSafeToRemove is used to remove any redundant uses of the iteration
count within the loop body.
Differential Revision: https://reviews.llvm.org/D74975
This moves all the logic of converting LLVM Triples to
MachO::CPU_(SUB_)TYPE from the specific target (Target)AsmBackend to
more convenient functions in lib/BinaryFormat.
This also gets rid of the separate two X86AsmBackend classes.
The previous attempt was to add it to libObject, but that adds an
unnecessary dependency to libObject from all the targets.
Differential Revision: https://reviews.llvm.org/D74808
