Commit Graph

141 Commits

Author SHA1 Message Date
Craig Topper 122c0e61f1 [TableGen] Use StringRef instead of std::string to split up a string that's being parsed. NFCI 2021-04-03 11:48:13 -07:00
Joerg Sonnenberger eb812efa12 Explicitly include <cassert> when using assert
Depending on the OS used, a module-enabled build can fail due to the
special handling <cassert> gets as textual header.
2020-03-02 22:45:28 +01:00
Vedant Kumar a9052b4dfc [AArch64] Add isAuthenticated predicate to MCInstDesc
Add a predicate to MCInstDesc that allows tools to determine whether an
instruction authenticates a pointer. This can be used by diagnostic
tools to hint at pointer authentication failures.

Differential Revision: https://reviews.llvm.org/D70329

rdar://55089604
2020-01-10 14:30:52 -08:00
Matt Arsenault 10edb1d0d4 TableGen/GlobalISel: Fix pattern matching of immarg literals
For arguments that are not expected to be materialized with
G_CONSTANT, this was emitting predicates which could never match. It
was first adding a meaningless LLT check, which would always fail due
to the operand not being a register.

Infer the cases where a literal should check for an immediate operand,
instead of a register This avoids needing to invent a special way of
representing timm literal values.

Also handle immediate arguments in GIM_CheckLiteralInt. The comments
stated it handled isImm() and isCImm(), but that wasn't really true.

This unblocks work on the selection of all of the complicated AMDGPU
intrinsics in future commits.
2020-01-09 17:37:52 -05:00
Simon Pilgrim cca01c0347 CodeGenInstruction - fix uninitialized variable warnings. NFCI. 2019-11-06 17:04:21 +00:00
Matt Arsenault 27269054d2 GlobalISel: Add target pre-isel instructions
Allows targets to introduce regbankselectable
pseudo-instructions. Currently the closet feature to this is an
intrinsic. However this requires creating a public intrinsic
declaration. This litters the public intrinsic namespace with
operations we don't necessarily want to expose to IR producers, and
would rather leave as private to the backend.

Use a new instruction bit. A previous attempt tried to keep using enum
value ranges, but it turned into a mess.

llvm-svn: 373937
2019-10-07 18:43:29 +00:00
Ulrich Weigand 6c5d5ce551 Allow target to handle STRICT floating-point nodes
The ISD::STRICT_ nodes used to implement the constrained floating-point
intrinsics are currently never passed to the target back-end, which makes
it impossible to handle them correctly (e.g. mark instructions are depending
on a floating-point status and control register, or mark instructions as
possibly trapping).

This patch allows the target to use setOperationAction to switch the action
on ISD::STRICT_ nodes to Legal. If this is done, the SelectionDAG common code
will stop converting the STRICT nodes to regular floating-point nodes, but
instead pass the STRICT nodes to the target using normal SelectionDAG
matching rules.

To avoid having the back-end duplicate all the floating-point instruction
patterns to handle both strict and non-strict variants, we make the MI
codegen explicitly aware of the floating-point exceptions by introducing
two new concepts:

- A new MCID flag "mayRaiseFPException" that the target should set on any
  instruction that possibly can raise FP exception according to the
  architecture definition.
- A new MI flag FPExcept that CodeGen/SelectionDAG will set on any MI
  instruction resulting from expansion of any constrained FP intrinsic.

Any MI instruction that is *both* marked as mayRaiseFPException *and*
FPExcept then needs to be considered as raising exceptions by MI-level
codegen (e.g. scheduling).

Setting those two new flags is straightforward. The mayRaiseFPException
flag is simply set via TableGen by marking all relevant instruction
patterns in the .td files.

The FPExcept flag is set in SDNodeFlags when creating the STRICT_ nodes
in the SelectionDAG, and gets inherited in the MachineSDNode nodes created
from it during instruction selection. The flag is then transfered to an
MIFlag when creating the MI from the MachineSDNode. This is handled just
like fast-math flags like no-nans are handled today.

This patch includes both common code changes required to implement the
new features, and the SystemZ implementation.

Reviewed By: andrew.w.kaylor

Differential Revision: https://reviews.llvm.org/D55506

llvm-svn: 362663
2019-06-05 22:33:10 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
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
2019-01-19 08:50:56 +00:00
Oliver Stannard 4cf35b4ab0 [ARM][MC] Move information about variadic register defs into tablegen
Currently, variadic operands on an MCInst are assumed to be uses,
because they come after the defs. However, this is not always the case,
for example the Arm/Thumb LDM instructions write to a variable number of
registers.

This adds a property of instruction definitions which can be used to
mark variadic operands as defs. This only affects MCInst, because
MachineInstruction already tracks use/def per operand in each instance
of the instruction, so can already represent this.

This property can then be checked in MCInstrDesc, allowing us to remove
some special cases in ARMAsmParser::isITBlockTerminator.

Differential revision: https://reviews.llvm.org/D54853

llvm-svn: 348114
2018-12-03 10:32:42 +00:00
Haojian Wu f838e90dcb Fix -Winfinite-recursion compile error.
llvm-svn: 347749
2018-11-28 12:32:53 +00:00
Simon Tatham 34860550f2 [TableGen] Better error checking for TIED_TO constraints.
There are quite strong constraints on how you can use the TIED_TO
constraint between MC operands, many of which are currently not
checked until compiler run time.

MachineVerifier enforces that operands can only be tied together in
pairs (no three-way ties), and MachineInstr::tieOperands enforces that
one of the tied operands must be an output operand (def) and the other
must be an input operand (use).

Now we check these at TableGen time, so that if you violate any of
them in a new instruction definition, you find out immediately,
instead of having to wait until you compile something that makes code
generation hit one of those assertions.

Also in this commit, all the error reports in ParseConstraint now
include the name and source location of the def where the problem
happened, so that if you do trigger any of these errors, it's easier
to find the part of your TableGen input where you made the mistake.

The trunk sources already build successfully with this additional
error check, so I think no in-tree target has any of these problems.

Reviewers: fhahn, lhames, nhaehnle, MatzeB

Reviewed By: MatzeB

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D53815

llvm-svn: 347743
2018-11-28 11:43:49 +00:00
Heejin Ahn ed5e06b0a7 [WebAssembly] Add isEHScopeReturn instruction property
Summary:
So far, `isReturn` property is used to mean both a return instruction
from a functon and the end of an EH scope, a scope that starts with a EH
scope entry BB and ends with a catchret or a cleanupret instruction.
Because WinEH uses funclets, all EH-scope-ending instructions are also
real return instruction from a function. But for wasm, they only serve
as the end marker of an EH scope but not a return instruction that
exits a function. This mismatch caused incorrect prolog and epilog
generation in wasm EH scopes. This patch fixes this.

This patch is in the same vein with rL333045, which splits
`MachineBasicBlock::isEHFuncletEntry` into `isEHFuncletEntry` and
`isEHScopeEntry`.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D50653

llvm-svn: 340325
2018-08-21 19:44:11 +00:00
Joel Galenson 06e7e5798f [cfi-verify] Support AArch64.
This patch adds support for AArch64 to cfi-verify.

This required three changes to cfi-verify.  First, it generalizes checking if an instruction is a trap by adding a new isTrap flag to TableGen (and defining it for x86 and AArch64).  Second, the code that ensures that the operand register is not clobbered between the CFI check and the indirect call needs to allow a single dereference (in x86 this happens as part of the jump instruction).  Third, we needed to ensure that return instructions are not counted as indirect branches.  Technically, returns are indirect branches and can be covered by CFI, but LLVM's forward-edge CFI does not protect them, and x86 does not consider them, so we keep that behavior.

In addition, we had to improve AArch64's code to evaluate the branch target of a MCInst to handle calls where the destination is not the first operand (which it often is not).

Differential Revision: https://reviews.llvm.org/D48836

llvm-svn: 337007
2018-07-13 15:19:33 +00:00
Ulrich Weigand c48aefb63b [TableGen] Support multi-alternative pattern fragments
A TableGen instruction record usually contains a DAG pattern that will
describe the SelectionDAG operation that can be implemented by this
instruction. However, there will be cases where several different DAG
patterns can all be implemented by the same instruction. The way to
represent this today is to write additional patterns in the Pattern
(or usually Pat) class that map those extra DAG patterns to the
instruction. This usually also works fine.

However, I've noticed cases where the current setup seems to require
quite a bit of extra (and duplicated) text in the target .td files.
For example, in the SystemZ back-end, there are quite a number of
instructions that can implement an "add-with-overflow" operation.
The same instructions also need to be used to implement just plain
addition (simply ignoring the extra overflow output). The current
solution requires creating extra Pat pattern for every instruction,
duplicating the information about which particular add operands
map best to which particular instruction.

This patch enhances TableGen to support a new PatFrags class, which
can be used to encapsulate multiple alternative patterns that may
all match to the same instruction.  It operates the same way as the
existing PatFrag class, except that it accepts a list of DAG patterns
to match instead of just a single one.  As an example, we can now define
a PatFrags to match either an "add-with-overflow" or a regular add
operation:

  def z_sadd : PatFrags<(ops node:$src1, node:$src2),
                        [(z_saddo node:$src1, node:$src2),
                         (add node:$src1, node:$src2)]>;

and then use this in the add instruction pattern:

  defm AR : BinaryRRAndK<"ar", 0x1A, 0xB9F8, z_sadd, GR32, GR32>;

These SystemZ target changes are implemented here as well.


Note that PatFrag is now defined as a subclass of PatFrags, which
means that some users of internals of PatFrag need to be updated.
(E.g. instead of using PatFrag.Fragment you now need to use
!head(PatFrag.Fragments).)


The implementation is based on the following main ideas:
- InlinePatternFragments may now replace each original pattern
  with several result patterns, not just one.
- parseInstructionPattern delays calling InlinePatternFragments
  and InferAllTypes.  Instead, it extracts a single DAG match
  pattern from the main instruction pattern.
- Processing of the DAG match pattern part of the main instruction
  pattern now shares most code with processing match patterns from
  the Pattern class.
- Direct use of main instruction patterns in InferFromPattern and
  EmitResultInstructionAsOperand is removed; everything now operates
  solely on DAG match patterns.


Reviewed by: hfinkel

Differential Revision: https://reviews.llvm.org/D48545

llvm-svn: 336999
2018-07-13 13:18:00 +00:00
Craig Topper 2be74395cf [TableGen] Prevent double flattening of InstAlias asm strings in the asm matcher emitter.
Unlike CodeGenInstruction, CodeGenInstAlias was flatting asm strings in its constructor. For instructions it was the users responsibility to flatten the string.

AsmMatcherEmitter didn't know this and treated them the same. This caused double flattening of InstAliases. This is mostly harmless unless the desired assembly string contains curly braces. The second flattening wouldn't know to ignore these and would remove the curly braces. And for variant 1 it would remove the contents of them as well.

To mitigate this, this patch makes removes the flattening from the CodeGenIntAlias constructor and modifies AsmWriterEmitter to account for the flattening not having been done.

llvm-svn: 334919
2018-06-18 01:28:01 +00:00
Petar Jovanovic c051000b83 [X86][MIPS][ARM] New machine instruction property 'isMoveReg'
This property is needed in order to follow values movement between
registers. This property is used in TII to implement method that
returns true if simple copy like instruction is recognized, along
with source and destination machine operands.

Patch by Nikola Prica.

Differential Revision: https://reviews.llvm.org/D45204

llvm-svn: 333093
2018-05-23 15:28:28 +00:00
Simon Dardis 13de555737 [FastISel] Permit instructions to be skipped for FastISel generation.
Some ISA's such as microMIPS32(R6) have instructions which are near identical
for code generation purposes, e.g. xor and xor16. These instructions take the
same value types for operands and return values, have the same
instruction predicates and map to the same ISD opcode. (These instructions do
differ by register classes.)

In such cases, the FastISel generator rejects the instruction definition.

This patch borrows the 'FastIselShouldIgnore' bit from rL129692 and enables
applying it to an instruction definition.

Reviewers: mcrosier

Differential Revision: https://reviews.llvm.org/D46953

llvm-svn: 332983
2018-05-22 14:36:58 +00:00
David Blaikie 13e77db2df Fix layering of MachineValueType.h by moving it from CodeGen to Support
This is used by llvm tblgen as well as by LLVM Targets, so the only
common place is Support for now. (maybe we need another target for these
sorts of things - but for now I'm at least making them correct & we can
make them better if/when people have strong feelings)

llvm-svn: 328395
2018-03-23 23:58:25 +00:00
Daniel Sanders c54aa9c844 [globalisel][tablegen] Generalize pointer-type inference by introducing ptypeN. NFC
ptypeN is functionally the same as typeN except that it informs the
SelectionDAG importer that an operand should be treated as a pointer even
if it was written as iN. This is important for patterns that use iN instead
of iPTR to represent pointers. E.g.:
  (set GPR64:$dst, (load GPR64:$addr))

Previously, this was handled as a hardcoded special case for the appropriate
operands to G_LOAD and G_STORE.

llvm-svn: 318574
2017-11-18 00:16:44 +00:00
Craig Topper 86a9aee88f [TableGen] Use StringRef instead of std::string for CodeGenInstruction namespace. NFC
llvm-svn: 307362
2017-07-07 06:22:35 +00:00
Sjoerd Meijer 724023a1ec This reapplies r281304. The issue was that I had missed
to copy the new isAdd field in the tablegen data structure.

llvm-svn: 281447
2016-09-14 08:20:03 +00:00
Sjoerd Meijer 520a18df9c Revert of r281304 as it is causing build bot failures in hexagon
hwloop regression tests. These tests pass locally; will be investigating
where these differences come from.

llvm-svn: 281306
2016-09-13 08:51:59 +00:00
Sjoerd Meijer 05453991fe This adds a new field isAdd to MCInstrDesc. The ARM and Hexagon instruction
descriptions now tag add instructions, and the Hexagon backend is using this to
identify loop induction statements.

Patch by Sam Parker and Sjoerd Meijer.

Differential Revision: https://reviews.llvm.org/D23601

llvm-svn: 281304
2016-09-13 08:08:06 +00:00
Benjamin Kramer 82de7d323d Apply clang-tidy's misc-move-constructor-init throughout LLVM.
No functionality change intended, maybe a tiny performance improvement.

llvm-svn: 270997
2016-05-27 14:27:24 +00:00
Mehdi Amini b550cb1750 [NFC] Header cleanup
Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
2016-04-18 09:17:29 +00:00
Matthias Braun 8e0a734fc5 TableGen: Add hasNoSchedulingInfo to instructions
This introduces a new flag that indicates that a specific instruction
will never be present when the MachineScheduler runs and therefore needs
no scheduling information.

This is in preparation for an upcoming commit which checks completeness
of a scheduling model when tablegen runs.

Differential Revision: http://reviews.llvm.org/D17728

llvm-svn: 262383
2016-03-01 20:03:11 +00:00
Craig Topper f7ce7242b7 [TableGen] Use the SMLoc header file instead of SourceMgr header file in a couple places. NFC
llvm-svn: 239274
2015-06-08 01:35:40 +00:00
Owen Anderson abaa523e9e Add support for the convergent flag at the MC and MachineInstr levels.
llvm-svn: 238450
2015-05-28 18:33:39 +00:00
Elena Demikhovsky 0995479e67 Reverted 230471 - gather scatter handling in table gen.
llvm-svn: 230892
2015-03-01 08:23:41 +00:00
Elena Demikhovsky 56eadcf5ce AVX-512: Gather and Scatter patterns
Gather and scatter instructions additionally write to one of the source operands - mask register.
In this case Gather has 2 destination values - the loaded value and the mask.
Till now we did not support code gen pattern for gather - the instruction was generated from 
intrinsic only and machine node was hardcoded.
When we introduce the masked_gather node, we need to select instruction automatically,
in the standard way.
I added a flag "hasTwoExplicitDefs" that allows to handle 2 destination operands.

(Some code in the X86InstrFragmentsSIMD.td is commented out, just to split one big
patch in many small patches)

llvm-svn: 230471
2015-02-25 09:46:31 +00:00
Craig Topper bf82611bc8 Remove neverHasSideEffects support from TableGen CodeGenInstruction. Everyone should use hasSideEffects now.
llvm-svn: 222809
2014-11-26 04:11:14 +00:00
Quentin Colombet 7e3da6677a Add isInsertSubreg property.
This patch adds a new property: isInsertSubreg and the related target hooks:
TargetIntrInfo::getInsertSubregInputs and
TargetInstrInfo::getInsertSubregLikeInputs to specify that a target specific
instruction is a (kind of) INSERT_SUBREG.

The approach is similar to r215394.

<rdar://problem/12702965>

llvm-svn: 216139
2014-08-20 23:49:36 +00:00
Quentin Colombet 7e75cbaf47 Add isExtractSubreg property.
This patch adds a new property: isExtractSubreg and the related target hooks:
TargetIntrInfo::getExtractSubregInputs and
TargetInstrInfo::getExtractSubregLikeInputs to specify that a target specific
instruction is a (kind of) EXTRACT_SUBREG.

The approach is similar to r215394.

<rdar://problem/12702965>

llvm-svn: 216130
2014-08-20 21:51:26 +00:00
Benjamin Kramer a7c40ef022 Canonicalize header guards into a common format.
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)

Changes made by clang-tidy with minor tweaks.

llvm-svn: 215558
2014-08-13 16:26:38 +00:00
Quentin Colombet d533cdf26f Add isRegSequence property.
This patch adds a new property: isRegSequence and the related target hooks: 
TargetIntrInfo::getRegSequenceInputs and 
TargetInstrInfo::getRegSequenceLikeInputs to specify that a target specific
instruction is a (kind of) REG_SEQUENCE.

<rdar://problem/12702965>

llvm-svn: 215394
2014-08-11 22:17:14 +00:00
Tim Northover 60091cfeb9 TableGen: use correct MIOperand when printing aliases
Previously, TableGen assumed that every aliased operand consumed precisely 1
MachineInstr slot (this was reasonable because until a couple of days ago,
nothing more complicated was eligible for printing).

This allows a couple more ARM64 aliases to print so we can remove the special
code.

On the X86 side, I've gone for explicit AT&T size specifiers as the default, so
turned off a few of the aliases that would have just started printing.

llvm-svn: 208880
2014-05-15 13:36:01 +00:00
Tim Northover d8d65a69cf TableGen/ARM64: print aliases even if they have syntax variants.
To get at least one use of the change (and some actual tests) in with its
commit, I've enabled the AArch64 & ARM64 NEON mov aliases.

llvm-svn: 208867
2014-05-15 11:16:32 +00:00
Jim Grosbach 56fd888e10 iterator_range accessor for CodeGenTarget instruction list.
llvm-svn: 206551
2014-04-18 02:09:02 +00:00
Jim Grosbach 0e28a3554b iterator based accessors for CodeGenInstruction operand list.
llvm-svn: 206550
2014-04-18 02:08:58 +00:00
Patrik Hagglund 8d09a6c674 Replace ValueTypes.h with MachineValueType.h if possible.
Utilize the previous move of MVT to a separate header for all trivial
cases (that don't need any further restructuring).

Reviewed By: Tim Northover

llvm-svn: 204003
2014-03-15 09:11:41 +00:00
Craig Topper bc9486bea0 Shrink the size of CodeGenInstruction a little bit by using bitfields. 32 bools seemed excessive.
llvm-svn: 200829
2014-02-05 09:10:40 +00:00
Joey Gouly 0e76fa7df5 Add an instruction deprecation feature to TableGen.
The 'Deprecated' class allows you to specify a SubtargetFeature that the
instruction is deprecated on.

The 'ComplexDeprecationPredicate' class allows you to define a custom
predicate that is called to check for deprecation.
For example:
  ComplexDeprecationPredicate<"MCR">

would mean you would have to define the following function:
  bool getMCRDeprecationInfo(MCInst &MI, MCSubtargetInfo &STI,
                             std::string &Info)

Which returns 'false' for not deprecated, and 'true' for deprecated
and store the warning message in 'Info'.

The MCTargetAsmParser constructor was chaned to take an extra argument of
the MCInstrInfo class, so out-of-tree targets will need to be changed.

llvm-svn: 190598
2013-09-12 10:28:05 +00:00
Chandler Carruth 91d19d8e93 Sort the #include lines for utils/...
I've tried to find main moudle headers where possible, but the TableGen
stuff may warrant someone else looking at it.

llvm-svn: 169251
2012-12-04 10:37:14 +00:00
Joerg Sonnenberger 635debe85b Remove exception handling usage from tblgen.
Most places can use PrintFatalError as the unwinding mechanism was not
used for anything other than printing the error. The single exception
was CodeGenDAGPatterns.cpp, where intermediate errors during type
resolution were ignored to simplify incremental platform development.
This use is replaced by an error flag in TreePattern and bailout earlier
in various places if it is set. 

llvm-svn: 166712
2012-10-25 20:33:17 +00:00
Jakob Stoklund Olesen 94ed4d42f8 Heed guessInstructionProperties, and stop warning on redundant flags.
Emit TableGen errors if guessInstructionProperties is 0 and
instruction properties can't be inferred from patterns.

Allow explicit instruction properties even when they can be inferred.

This patch doesn't change the TableGen output. Redundant properties
are not yet verified because the tree has errors.

llvm-svn: 162516
2012-08-24 00:31:16 +00:00
Jakob Stoklund Olesen af507bf450 Tristate mayLoad, mayStore, and hasSideEffects.
Keep track of the set/unset state of these bits along with their
true/false values, but treat '?' as '0' for now.

llvm-svn: 162461
2012-08-23 19:34:46 +00:00
Jakob Stoklund Olesen d7b66968f9 Print out the location of expanded multiclass defs in TableGen errors.
When reporting an error for a defm, we would previously only report the
location of the outer defm, which is not always where the error is.

Now we also print the location of the expanded multiclass defs:

lib/Target/X86/X86InstrSSE.td:2902:12: error: foo
  defm ADD : basic_sse12_fp_binop_s<0x58, "add", fadd, SSE_ALU_ITINS_S>,
             ^
lib/Target/X86/X86InstrSSE.td:2801:11: note: instantiated from multiclass
  defm PD : sse12_fp_packed<opc, !strconcat(OpcodeStr, "pd"), OpNode, VR128,
            ^
lib/Target/X86/X86InstrSSE.td:194:5: note: instantiated from multiclass
    def rm : PI<opc, MRMSrcMem, (outs RC:$dst), (ins RC:$src1, x86memop:$src2),
        ^

llvm-svn: 162409
2012-08-22 23:33:58 +00:00
Jakob Stoklund Olesen 2382d320b3 Add an MCID::Select flag and TII hooks for optimizing selects.
Select instructions pick one of two virtual registers based on a
condition, like x86 cmov. On targets like ARM that support predication,
selects can sometimes be eliminated by predicating the instruction
defining one of the operands.

Teach PeepholeOptimizer to recognize select instructions, and ask the
target to optimize them.

llvm-svn: 162059
2012-08-16 23:11:47 +00:00
Owen Anderson da6bd3e603 Teach the AsmMatcherEmitter to allow InstAlias' where the suboperands of a complex operand are called out explicitly in the asm string.
llvm-svn: 158183
2012-06-08 00:25:03 +00:00
Andrew Trick 52363bdbeb Restore hasPostISelHook tblgen flag.
No functionality change. The hook makes it explicit which patterns
require "special" handling. i.e. it self-documents tblgen
deficiencies. I plan to add verification in ExpandISelPseudos and
Thumb2SizeReduce to catch any missing hasPostISelHooks. Otherwise it's
too fragile.

llvm-svn: 140160
2011-09-20 18:22:31 +00:00