to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
SB (Speculative Barrier) is only mandatory from 8.5
onwards but is optional from Armv8.0-A. This patch adds a command
line option to enable SB, as it was previously only possible to
enable by selecting -march=armv8.5-a.
This patch also renames FeatureSpecRestrict to FeatureSB.
Reviewed By: olista01, LukeCheeseman
Differential Revision: https://reviews.llvm.org/D55990
llvm-svn: 350299
This mirrors what we already do for AArch64 as the cores are similar.
As discussed in the review, enabling the machine scheduler causes
more variations in performance changes so it is not enabled for now.
This patch improves LNT scores by a geomean of 1.57% at -O3.
Differential Revision: https://reviews.llvm.org/D53562
llvm-svn: 345272
This is a new barrier which limits speculative execution of the
instructions following it.
Patch by Pablo Barrio!
Differential revision: https://reviews.llvm.org/D52477
llvm-svn: 343213
This patch allows targeting Armv8.5-A, adding the architecture to
tablegen and setting the options to be identical to Armv8.4-A for the
time being. Subsequent patches will add support for the different
features included in the Armv8.5-A Reference Manual.
Patch by Pablo Barrio!
Differential revision: https://reviews.llvm.org/D52470
llvm-svn: 343102
A sequence of VMUL and VADD instructions always give the same or better
performance than a fused VMLA instruction on the Cortex-M4 and Cortex-M33.
Executing the VMUL and VADD back-to-back requires the same cycles, but
having separate instructions allows scheduling to avoid the hazard between
these 2 instructions.
Differential Revision: https://reviews.llvm.org/D52289
llvm-svn: 342874
The Technical Reference Manuals for these two CPUs state that branching
to an unaligned 32-bit instruction incurs an extra pipeline reload
penalty. That's bad.
This also enables the optimization at -Os since it costs on average one
byte per loop in return for 1 cycle per iteration, which is pretty good
going.
llvm-svn: 342127
Add +fp16fml feature for new FP16 instructions, which are a
mandatory part of FP16 from v8.4-A and an optional part of FP16
from v8.2-A. It doesn't seem to be possible to model this in
LLVM, but the relationship between the options is handled by
the related clang patch.
In keeping with what I think is the usual practice, the fp16fml
extension is accepted regardless of base architecture version.
Builds on/replaces Sjoerd Meijer's patch to add these instructions at
https://reviews.llvm.org/D49839.
Differential Revision: https://reviews.llvm.org/D50228
llvm-svn: 340013
This feature enables the fusion of such operations on Cortex A57 and Cortex
A72, as recommended in their Software Optimisation Guides, sections 4.14 and
4.11, respectively.
Differential revision: https://reviews.llvm.org/D49563
llvm-svn: 338147
Enable the optimization of operations on DPR and SPR via a feature instead
of checking the target.
Differential revision: https://reviews.llvm.org/D49463
llvm-svn: 337575
Initial patch adding assembly support for Armv8.4-A.
Besides adding v8.4 as a supported architecture to the usual places, this also
adds target features for the different crypto algorithms. Armv8.4-A introduced
new crypto algorithms, made them optional, and allows different combinations:
- none of the v8.4 crypto functions are supported, which is independent of the
implementation of the Armv8.0 SHA1 and SHA2 instructions.
- the v8.4 SHA512 and SHA3 support is implemented, in this case the Armv8.0
SHA1 and SHA2 instructions must also be implemented.
- the v8.4 SM3 and SM4 support is implemented, which is independent of the
implementation of the Armv8.0 SHA1 and SHA2 instructions.
- all of the v8.4 crypto functions are supported, in this case the Armv8.0 SHA1
and SHA2 instructions must also be implemented.
The v8.4 crypto instructions are added to AArch64 only, and not AArch32,
and are made optional extensions to Armv8.2-A.
The user-facing Clang options will map on these new target features, their
naming will be compatible with GCC and added in follow-up patches.
The Armv8.4-A instruction sets can be downloaded here:
https://developer.arm.com/products/architecture/a-profile/exploration-tools
Differential Revision: https://reviews.llvm.org/D48625
llvm-svn: 335953
This sets target feature FeatureStrictAlign for Armv6-m and Armv8-m.baseline,
because it has no support for unaligned accesses.
It looks like we always pass target feature "+strict-align" from
Clang, so this is not a user facing problem, but querying the subtarget
(in e.g. llc) for unaligned access support is incorrect.
Differential Revision: https://reviews.llvm.org/D48437
llvm-svn: 335326
This option allows codegen (such as DAGCombine or MI scheduling) to use alias
analysis information, which can help with the codegen on in-order cpu's,
especially machine scheduling. Here I have done things the same way as AArch64,
adding a subtarget feature to enable this for specific cores, and enabled it for
the R52 where we have a schedule to make use of it.
Differential Revision: https://reviews.llvm.org/D48074
llvm-svn: 335249
Back when the R52 schedule was added in rL286949, there was no way
to enable machine schedules in ARM for specific cores. Since then a
target feature has been added. This enables the feature for R52,
removing the need to manually specify compiler flags.
llvm-svn: 331027
Summary:
Add a target option AllowRegisterRenaming that is used to opt in to
post-register-allocation renaming of registers. This is set to 0 by
default, which causes the hasExtraSrcRegAllocReq/hasExtraDstRegAllocReq
fields of all opcodes to be set to 1, causing
MachineOperand::isRenamable to always return false.
Set the AllowRegisterRenaming flag to 1 for all in-tree targets that
have lit tests that were effected by enabling COPY forwarding in
MachineCopyPropagation (AArch64, AMDGPU, ARM, Hexagon, Mips, PowerPC,
RISCV, Sparc, SystemZ and X86).
Add some more comments describing the semantics of the
MachineOperand::isRenamable function and how it is set and maintained.
Change isRenamable to check the operand's opcode
hasExtraSrcRegAllocReq/hasExtraDstRegAllocReq bit directly instead of
relying on it being consistently reflected in the IsRenamable bit
setting.
Clear the IsRenamable bit when changing an operand's register value.
Remove target code that was clearing the IsRenamable bit when changing
registers/opcodes now that this is done conservatively by default.
Change setting of hasExtraSrcRegAllocReq in AMDGPU target to be done in
one place covering all opcodes that have constant pipe read limit
restrictions.
Reviewers: qcolombet, MatzeB
Subscribers: aemerson, arsenm, jyknight, mcrosier, sdardis, nhaehnle, javed.absar, tpr, arichardson, kristof.beyls, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, jordy.potman.lists, apazos, sabuasal, niosHD, escha, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D43042
llvm-svn: 325931
This converts the ARM AsmParser to use the new assembly matcher error
reporting mechanism, which allows errors to be reported for multiple
instruction encodings when it is ambiguous which one the user intended
to use.
By itself this doesn't improve many error messages, because we don't have
diagnostic text for most operand types, but as we add that then this will allow
more of those diagnostic strings to be used when they are relevant.
Differential revision: https://reviews.llvm.org/D31530
llvm-svn: 314779
Replace the UsePostRAScheduler SubtargetFeature with
DisablePostRAScheduler, which is then used by Swift and Cyclone.
This patch maintains enabling PostRA scheduling for other Thumb2
capable cores and/or for functions which are being compiled in Arm
mode.
Differential Revision: https://reviews.llvm.org/D37055
llvm-svn: 312226
This patch adds the option to allow also using the PostRA scheduler,
which brings the ARM backend inline with AArch64 targets. The
SchedModel can also set 'PostRAScheduler', as the R52 does, so also
query this property in the overridden function.
Differential Revision: https://reviews.llvm.org/D36866
llvm-svn: 311162
Summary:
By removing FeatureNoARM implies ModeThumb, we can detect cases where a
function's target-features contain -thumb-mode (enables ARM codegen for the
function), but the architecture does not support ARM mode. Previously, the
implication caused the FeatureNoARM bit to be cleared for functions with
-thumb-mode, making the assertion in ARMSubtarget::ARMSubtarget [1]
pointless for such functions.
This assertion is the only guard against generating ARM code for
architectures without ARM codegen support. Is there a place where we
could easily generate error messages for the user? At the moment, we
would generate ARM code for Thumb-only architectures. X86 has the same
behavior as ARM, as in it only has an assertion and no error message,
but I think for ARM an error message would be helpful. What do you
think?
For the example below, `llc -mtriple=armv7m-eabi test.ll -o -` will
generate ARM assembler (or fail with an assertion error with this patch).
Note that if we run the resulting assembler through llvm-mc, we get
an appropriate error message, but not when codegen is handled
through clang.
```
define void @bar() #0 {
entry:
ret void
}
attributes #0 = { "target-features"="-thumb-mode" }
```
[1] c1f7b54cef/lib/Target/ARM/ARMSubtarget.cpp (L147)
Reviewers: t.p.northover, rengolin, peter.smith, aadg, silviu.baranga, richard.barton.arm, echristo
Reviewed By: rengolin, echristo
Subscribers: efriedma, aemerson, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D35569
llvm-svn: 310476
This patch enables choice for accessing thread local
storage pointer (like '-mtp' in gcc).
Differential Revision: https://reviews.llvm.org/D34408
llvm-svn: 309381
Summary:
This change makes it easier to experiment with the MachineScheduler in
the ARM backend and also makes it very explicit which CPUs use the
MachineScheduler (currently only swift and cyclone).
Reviewers: MatzeB, t.p.northover, javed.absar
Reviewed By: MatzeB
Subscribers: aemerson, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D35935
llvm-svn: 309316
This patch tidies up and organises ARM.td
so that it is easier to understandand
and extend in the future.
Reviewed by: @hahn, @rovka
Differential Revision: https://reviews.llvm.org/D35248
llvm-svn: 307897
The current heuristic in isProfitableToIfCvt assumes we have a branch predictor,
and so gives the wrong answer in some cases when we don't. This patch adds a
subtarget feature to indicate that a subtarget has no branch predictor, and
changes the heuristic in isProfitableToiIfCvt when it's present. This gives a
slight overall improvement in a set of embedded benchmarks on Cortex-M4 and
Cortex-M33.
Differential Revision: https://reviews.llvm.org/D34398
llvm-svn: 306547
The benchmarking summarized in
http://lists.llvm.org/pipermail/llvm-dev/2017-May/113525.html showed
this is beneficial for a wide range of cores.
As is to be expected, quite a few small adaptations are needed to the
regressions tests, as the difference in scheduling results in:
- Quite a few small instruction schedule differences.
- A few changes in register allocation decisions caused by different
instruction schedules.
- A few changes in IfConversion decisions, due to a difference in
instruction schedule and/or the estimated cost of a branch mispredict.
llvm-svn: 306514
Summary:
This patch adds a macro fusion using CodeGen/MacroFusion.cpp to pair AES
instructions back to back and adds FeatureFuseAES to enable the feature.
Reviewers: evandro, javed.absar, rengolin, t.p.northover
Reviewed By: javed.absar
Subscribers: aemerson, mgorny, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D34142
llvm-svn: 305988
I doubt anyone actually uses it, and I'm not even entirely convinced it exists
myself; but it is our default for "clang -arch armv6". Functionally, if it does
exist it's identical to the arm1176jz-f from LLVM's point of view (the
difference is apparently in the "Security Extensions").
llvm-svn: 301962
The hardware div feature refers only to Thumb, but because of its name
it is tempting to use it to check for hardware division in general,
which may cause problems in ARM mode. See https://reviews.llvm.org/D32005.
This patch adds "Thumb" to its name, to make its scope clear. One
notable place where I haven't made the change is in the feature flag
(used with -mattr), which is still hwdiv. Changing it would also require
changes in a lot of tests, including clang tests, and it doesn't seem
like it's worth the effort.
Differential Revision: https://reviews.llvm.org/D32160
llvm-svn: 300827
Summary:
Host CPU detection now supports Kryo, so we need to recognize it in ARM
target.
Reviewers: mcrosier, t.p.northover, rengolin, echristo, srhines
Reviewed By: t.p.northover, echristo
Subscribers: aemerson
Differential Revision: https://reviews.llvm.org/D31775
llvm-svn: 299674
Summary:
To support negative immediates for certain arithmetic instructions, the
instruction is converted to the inverse instruction with a negated (or inverted)
immediate. For example, "ADD r0, r1, #FFFFFFFF" cannot be encoded as an ADD
instruction. However, "SUB r0, r1, #1" is equivalent.
These conversions are different from instruction aliases. An alias maps
several assembler instructions onto one encoding. A conversion, however, maps
an *invalid* instruction--e.g. with an immediate that cannot be represented in
the encoding--to a different (but equivalent) instruction.
Several instructions with negative immediates were being converted already, but
this was not systematically tested, nor did it cover all instructions.
This patch implements all possible substitutions for ARM, Thumb1 and
Thumb2 assembler and adds tests. It also adds a feature flag
(-mattr=+no-neg-immediates) to turn these substitutions off. This is
helpful for users who want their code to assemble to exactly what they
wrote.
Reviewers: t.p.northover, rovka, samparker, javed.absar, peter.smith, rengolin
Reviewed By: javed.absar
Subscribers: aadg, aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D30571
llvm-svn: 298380
Removed the HasT2ExtractPack feature and replaced its references
with HasDSP. This then allows the Thumb2 extend instructions to be
selected for ARMv8M +dsp. These instruction descriptions have also
been refactored and more target tests have been added for their isel.
Differential Revision: https://reviews.llvm.org/D29623
llvm-svn: 295452
Chandler Carruth