61 Commits

Author SHA1 Message Date
Sergei Barannikov
01a7967447 [CodeGen] Replace CCState's getNextStackOffset with getStackSize (NFC)
The term "next stack offset" is misleading because the next argument is
not necessarily allocated at this offset due to alignment constrains.
It also does not make much sense when allocating arguments at negative
offsets (introduced in a follow-up patch), because the returned offset
would be past the end of the next argument.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D149566
2023-05-17 21:51:45 +03:00
Diana Picus
f95a5fbe7c MachineIRBuilder: Rename buildMerge. NFC
`buildMerge` may build a G_MERGE_VALUES, G_BUILD_VECTOR or
G_CONCAT_VECTORS. Rename it to `buildMergeLikeInstr`.

This is a follow-up suggested in https://reviews.llvm.org/D140964

Differential Revision: https://reviews.llvm.org/D141372
2023-01-13 09:32:58 +01:00
Zongwei Lan
ad73ce318e [Target] use getSubtarget<> instead of static_cast<>(getSubtarget())
Differential Revision: https://reviews.llvm.org/D125391
2022-05-26 11:22:41 -07:00
serge-sans-paille
989f1c72e0 Cleanup codegen includes
This is a (fixed) recommit of https://reviews.llvm.org/D121169

after:  1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D121681
2022-03-16 08:43:00 +01:00
Nico Weber
a278250b0f Revert "Cleanup codegen includes"
This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169
2022-03-10 07:59:22 -05:00
serge-sans-paille
7f230feeea Cleanup codegen includes
after:  1061034926
before: 1063332844

Differential Revision: https://reviews.llvm.org/D121169
2022-03-10 10:00:30 +01:00
Benjamin Kramer
9b8b16457c Put implementation details into anonymous namespaces. NFCI. 2021-11-07 15:18:30 +01:00
Amara Emerson
8bde5e58c0 Delay outgoing register assignments to last.
The delayed stack protector feature which is currently used for SDAG (and thus
allows for more commonly generating tail calls) depends on being able to extract
the tail call into a separate return block. To do this it also has to extract
the vreg->physreg copies that set up the call's arguments, since if it doesn't
then the call inst ends up using undefined physregs in it's new spliced block.

SelectionDAG implementations can do this because they delay emitting register
copies until  *after* the stack arguments are set up. GISel however just
processes and emits the arguments in IR order, so stack arguments always end up
last, and thus this breaks the code that looks for any register arg copies that
precede the call instruction.

This patch adds a thunk argument to the assignValueToReg() and custom assignment
hooks. For outgoing arguments, register assignments use this return param to
return a thunk that does the actual generating of the copies. We collect these
until all the outgoing stack assignments have been done and then execute them,
so that the copies (and perhaps some artifacts like G_SEXTs) are placed after
any stores.

Differential Revision: https://reviews.llvm.org/D110610
2021-10-04 12:33:20 -07:00
Matt Arsenault
9ad1a49956 Mips/GlobalISel: Use LLT form of getMachineMemOperand
NFC here since it's just using a scalar anyway.
2021-07-16 11:41:32 -04:00
Matt Arsenault
121541fdcd Mips/GlobalISel: Use more standard call lowering infrastructure
This also fixes some missing implicit uses on call instructions, adds
missing G_ASSERT_SEXT/ZEXT annotations, and some missing outgoing
sext/zexts. This also fixes not respecting tablegen requested type
promotions.

This starts treating f64 passed in i32 GPRs as a type of custom
assignment, which restores some previously XFAILed tests. This is due
to getNumRegistersForCallingConv returns a static value, but in this
case it is context dependent on other arguments.

Most of the ugliness is reproducing a hack CC_MipsO32 uses in
SelectionDAG. CC_MipsO32 depends on a bunch of vectors populated from
the original IR argument types in MipsCCState. The way this ends up
working in GlobalISel is it only ends up inspecting the most recently
added vector element. I'm pretty sure there are cleaner ways to do
this, but this seemed easier than fixing up the current DAG
handling. This is another case where it would be easier of the
CCAssignFns were passed the original type instead of only the
pre-legalized ones.

There's still a lot of junk here that shouldn't be necessary. This
also likely breaks big endian handling, but it wasn't complete/tested
anyway since the IRTranslator gives up on big endian targets.
2021-07-13 11:04:10 -04:00
Matt Arsenault
43f25e61ce Mips/GlobalISel: Remove custom splitToValueTypes 2021-07-08 13:39:06 -04:00
Matt Arsenault
9b057f647d GlobalISel: Track original argument index in ArgInfo
SelectionDAG's equivalents in ISD::InputArg/OutputArg track the
original argument index. Mips relies on this, and its currently
reinventing its own parallel CallLowering infrastructure which tracks
these indexes on the side. Add this to help move towards deleting the
custom mips handling.
2021-07-08 13:39:02 -04:00
Matt Arsenault
2f9504aa41 Mips/GlobalISel: Use correct callee calling convention
This was using the convention from the calling function.
2021-07-08 13:38:57 -04:00
Nick Desaulniers
3787ee4571 reland [IR] make -stack-alignment= into a module attr
Relands commit 433c8d950cb3a1fa0977355ce0367e8c763a3f13 with fixes for
MIPS.

Similar to D102742, specifying the stack alignment via CodegenOpts means
that this flag gets dropped during LTO, unless the command line is
re-specified as a plugin opt. Instead, encode this information as a
module level attribute so that we don't have to expose this llvm
internal flag when linking the Linux kernel with LTO.

Looks like external dependencies might need a fix:
* https://github.com/llvm-hs/llvm-hs/issues/345
* https://github.com/halide/Halide/issues/6079

Link: https://github.com/ClangBuiltLinux/linux/issues/1377

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D103048
2021-06-08 10:59:46 -07:00
Matt Arsenault
6b76d82853 GlobalISel: Fix marking byval arguments as immutable
byval arguments need to be assumed writable. Only implicitly stack
passed arguments which aren't addressable in the IR can be assumed
immutable.

Mips is still broken since for some reason its doing its own thing
with the ValueHandlers (and x86 doesn't actually handle byval
arguments now, although some of the code is there).
2021-03-12 09:01:53 -05:00
Matt Arsenault
6c260d3bc0 GlobalISel: Move splitToValueTypes to generic code
I copied the nearly identical function from AArch64 into AMDGPU, so
fix this duplication.

Mips and X86 have their own more exotic versions which should be
removed. However replacing those is better left for a separate patch
since it requires other changes to avoid regressions.
2021-03-01 08:58:18 -05:00
Christudasan Devadasan
d68458bd56 [GlobalISel] Base implementation for sret demotion.
If the return values can't be lowered to registers
SelectionDAG performs the sret demotion. This patch
contains the basic implementation for the same in
the GlobalISel pipeline.

Furthermore, targets should bring relevant changes
during lowerFormalArguments, lowerReturn and
lowerCall to make use of this feature.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D92953
2021-01-06 10:30:50 +05:30
David Sherwood
47f2dc7e5f [SVE][NFC] Replace some TypeSize comparisons in non-AArch64 Targets
In most of lib/Target we know that we are not dealing with scalable
types so it's perfectly fine to replace TypeSize comparison operators
with their fixed width equivalents, making use of getFixedSize()
and so on.

Differential Revision: https://reviews.llvm.org/D89101
2020-10-15 09:01:21 +01:00
Matt Arsenault
0c92bfa4b8 GlobalISel: Don't use virtual for distinguishing arg handlers
There's no reason to involve the hassle of a virtual method targets
have to override for a simple boolean.

Not sure exactly what's going on with Mips, but it seems to define its
own totally separate handler classes.
2020-07-22 14:14:43 -04:00
Matt Arsenault
669bb3111f Mips: Don't store MachineFunction in MipsFunctionInfo
It will soon be disallowed to depend on MachineFunction state on
construction.
2020-06-30 16:08:51 -04:00
Guillaume Chatelet
1778564f91 [Alignment][NFC] Migrate the rest of backends
Summary: This is a followup on D81196

Reviewers: courbet

Subscribers: arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81278
2020-06-08 07:17:20 +00:00
Guillaume Chatelet
c9d5c19597 [Alignment][NFC] Transitionning more getMachineMemOperand call sites
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: arsenm, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, Jim, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77121
2020-03-31 08:36:18 +00:00
Guillaume Chatelet
bdf77209b9 [Alignment][NFC] Use Align version of getMachineMemOperand
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jyknight, sdardis, nemanjai, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, jfb, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77059
2020-03-30 15:46:27 +00:00
Guillaume Chatelet
3ba550a05a [Alignment][NFC] Use TFL::getStackAlign()
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: dylanmckay, sdardis, nemanjai, hiraditya, kbarton, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D76551
2020-03-23 13:48:29 +01:00
Petar Avramovic
92c80529dd [MIPS GlobalISel] RegBankSelect G_MERGE_VALUES and G_UNMERGE_VALUES
Consider large operands in G_MERGE_VALUES and G_UNMERGE_VALUES as
Ambiguous during regbank selection.
Introducing new InstType AmbiguousWithMergeOrUnmerge which will
allow us to recognize whether to narrow scalar or use s64:fprb.

This change exposed a bug when reusing data from TypeInfoForMF.
Thus when Instr is about to get destroyed (using narrow scalar)
clear its data in TypeInfoForMF. Internal data is saved based on
Instr's address, and it will no longer be valid.
Add detailed asserts for InstType and operand size.

Generate generic instructions instead of MIPS target instructions
during argument lowering and custom legalizer.
Select G_UNMERGE_VALUES and G_MERGE_VALUES when proper banks are
selected: {s32:gprb, s32:gprb, s64:fprb} for G_UNMERGE_VALUES and
{s64:fprb, s32:gprb, s32:gprb} for G_MERGE_VALUES.
Update tests. One improvement is when floating point argument in
gpr(or two gprs) gets passed to another function through gpr
unnecessary fpr-to-gpr moves are no longer generated.

Differential Revision: https://reviews.llvm.org/D74623
2020-02-19 10:09:52 +01:00
Jay Foad
2a1b5af299 [GlobalISel] Tidy up unnecessary calls to createGenericVirtualRegister
Summary:
As a side effect some redundant copies of constant values are removed by
CSEMIRBuilder.

Reviewers: aemerson, arsenm, dsanders, aditya_nandakumar

Subscribers: sdardis, jvesely, wdng, nhaehnle, rovka, hiraditya, jrtc27, atanasyan, volkan, Petar.Avramovic, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73789
2020-01-31 17:07:16 +00:00
Guillaume Chatelet
805c157e8a [Alignment][NFC] Deprecate Align::None()
Summary:
This is a follow up on https://reviews.llvm.org/D71473#inline-647262.
There's a caveat here that `Align(1)` relies on the compiler understanding of `Log2_64` implementation to produce good code. One could use `Align()` as a replacement but I believe it is less clear that the alignment is one in that case.

Reviewers: xbolva00, courbet, bollu

Subscribers: arsenm, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, jsji, Jim, kerbowa, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D73099
2020-01-24 12:53:58 +01:00
Daniel Sanders
e74c5b9661 [globalisel] Rename G_GEP to G_PTR_ADD
Summary:
G_GEP is rather poorly named. It's a simple pointer+scalar addition and
doesn't support any of the complexities of getelementptr. I therefore
propose that we rename it. There's a G_PTR_MASK so let's follow that
convention and go with G_PTR_ADD

Reviewers: volkan, aditya_nandakumar, bogner, rovka, arsenm

Subscribers: sdardis, jvesely, wdng, nhaehnle, hiraditya, jrtc27, atanasyan, arphaman, Petar.Avramovic, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69734
2019-11-05 10:31:17 -08:00
Simon Atanasyan
0bd82a96cc [mips] Split long lines in the code. NFC 2019-11-03 00:50:52 +03:00
Guillaume Chatelet
bac5f6bd21 [Alignment][NFC] TargetCallingConv::setOrigAlign and TargetLowering::getABIAlignmentForCallingConv
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: sdardis, hiraditya, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69243

llvm-svn: 375407
2019-10-21 11:01:55 +00:00
Petar Avramovic
ed3051917e [MIPS GlobalISel] Lower aggregate structure return arguments
Implement aggregate structure split to simpler types in splitToValueTypes.
splitToValueTypes is used for return values.
According to MipsABIInfo from clang/lib/CodeGen/TargetInfo.cpp,
aggregate structure arguments for O32 always get simplified and thus
will remain unsupported by the MIPS GlobalISel for the time being.
For O32, aggregate structures can be encountered only for complex number
returns e.g. 'complex float' or 'complex double' from <complex.h>.

Differential Revision: https://reviews.llvm.org/D67963

llvm-svn: 372957
2019-09-26 10:48:07 +00:00
Petar Avramovic
c063b0b0d3 [MIPS GlobalISel] VarArg argument lowering, select G_VASTART and vacopy
CC_Mips doesn't accept vararg functions for O32, so we have to explicitly
use CC_Mips_FixedArg.
For lowerCall we now properly figure out whether callee function is vararg
or not, this has no effect for O32 since we always use CC_Mips_FixedArg.
For lower formal arguments we need to copy arguments in register to stack
and save pointer to start for argument list into MipsMachineFunction
object so that G_VASTART could use it during instruction select.
For vacopy we need to copy content from one vreg to another,
load and store are used for that purpose.

Differential Revision: https://reviews.llvm.org/D67756

llvm-svn: 372555
2019-09-23 08:11:41 +00:00
Petar Avramovic
d2574d79b6 [MIPS GlobalISel] Lower SRet pointer arguments
Instead of returning structure by value clang usually adds pointer
to that structure as an argument. Pointers don't require special
handling no matter the SRet flag. Remove unsuccessful exit from
lowerCall for arguments with SRet flag if they are pointers.

Differential Revision: https://reviews.llvm.org/D67179

llvm-svn: 371054
2019-09-05 11:12:01 +00:00
Amara Emerson
fbaf425b79 [GlobalISel][CallLowering] Add support for splitting types according to calling conventions.
On AArch64, s128 types have to be split into s64 GPRs when passed as arguments.
This change adds the generic support in call lowering for dealing with multiple
registers, for incoming and outgoing args.

Support for splitting for return types not yet implemented.

Differential Revision: https://reviews.llvm.org/D66180

llvm-svn: 370822
2019-09-03 21:42:28 +00:00
Tim Northover
e1a5f668b3 GlobalISel: pack various parameters for lowerCall into a struct.
I've now needed to add an extra parameter to this call twice recently. Not only
is the signature getting extremely unwieldy, but just updating all of the
callsites and implementations is a pain. Putting the parameters in a struct
sidesteps both issues.

llvm-svn: 368408
2019-08-09 08:26:38 +00:00
Tim Northover
522fb7eedc GlobalISel: support swiftself attribute
llvm-svn: 367683
2019-08-02 14:09:49 +00:00
Mark Lacey
7b8d3eb9e2 [GISel] Pass MD_callees metadata down in call lowering.
Summary:
This will make it possible to improve IPRA by taking into account
register usage in indirect calls.

NFC yet; this is just laying the groundwork to start building
up patches to take advantage of the information for improved register
allocation.

Reviewers: aditya_nandakumar, volkan, qcolombet, arsenm, rovka, aemerson, paquette

Subscribers: sdardis, wdng, javed.absar, hiraditya, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65488

llvm-svn: 367476
2019-07-31 20:34:02 +00:00
Petar Avramovic
cf21794566 [MIPS GlobalISel] Fix check for void return during lowerCall
Void return used to have unsigned with value 0 for virtual register
but with addition of Register class and changes to arguments to lowerCall
this is no longer valid.
Check for void return by inspecting the Ty field in OrigRet.

Differential Revision: https://reviews.llvm.org/D65321

llvm-svn: 367107
2019-07-26 13:19:37 +00:00
Matt Arsenault
079f77b590 GlobalISel: Convert some build functions to using SrcOp/DstOp
llvm-svn: 365343
2019-07-08 16:27:47 +00:00
Diana Picus
8138996128 [GlobalISel] Accept multiple vregs for lowerCall's result
Change the interface of CallLowering::lowerCall to accept several
virtual registers for the call result, instead of just one.  This is a
follow-up to D46018.

CallLowering::lowerReturn was similarly refactored in D49660 and
lowerFormalArguments in D63549.

With this change, we no longer pack the virtual registers generated for
aggregates into one big lump before delegating to the target. Therefore,
the target can decide itself whether it wants to handle them as separate
pieces or use one big register.

ARM and AArch64 have been updated to use the passed in virtual registers
directly, which means we no longer need to generate so many
merge/extract instructions.

NFCI for AMDGPU, Mips and X86.

Differential Revision: https://reviews.llvm.org/D63550

llvm-svn: 364511
2019-06-27 09:15:53 +00:00
Diana Picus
c3dbe23977 [GlobalISel] Accept multiple vregs in lowerFormalArgs
Change the interface of CallLowering::lowerFormalArguments to accept
several virtual registers for each formal argument, instead of just one.
This is a follow-up to D46018.

CallLowering::lowerReturn was similarly refactored in D49660. lowerCall
will be refactored in the same way in follow-up patches.

With this change, we forward the virtual registers generated for
aggregates to CallLowering. Therefore, the target can decide itself
whether it wants to handle them as separate pieces or use one big
register. We also copy the pack/unpackRegs helpers to CallLowering to
facilitate this.

ARM and AArch64 have been updated to use the passed in virtual registers
directly, which means we no longer need to generate so many
merge/extract instructions.

AArch64 seems to have had a bug when lowering e.g. [1 x i8*], which was
put into a s64 instead of a p0. Added a test-case which illustrates the
problem more clearly (it crashes without this patch) and fixed the
existing test-case to expect p0.

AMDGPU has been updated to unpack into the virtual registers for
kernels. I think the other code paths fall back for aggregates, so this
should be NFC.

Mips doesn't support aggregates yet, so it's also NFC.

x86 seems to have code for dealing with aggregates, but I couldn't find
the tests for it, so I just added a fallback to DAGISel if we get more
than one virtual register for an argument.

Differential Revision: https://reviews.llvm.org/D63549

llvm-svn: 364510
2019-06-27 08:54:17 +00:00
Diana Picus
69ce1c1319 [GlobalISel] Allow multiple VRegs in ArgInfo. NFC
Allow CallLowering::ArgInfo to contain more than one virtual register.
This is useful when passes split aggregates into several virtual
registers, but need to also provide information about the original type
to the call lowering. Used in follow-up patches.

Differential Revision: https://reviews.llvm.org/D63548

llvm-svn: 364509
2019-06-27 08:50:53 +00:00
Matt Arsenault
faeaedf8e9 GlobalISel: Remove unsigned variant of SrcOp
Force using Register.

One downside is the generated register enums require explicit
conversion.

llvm-svn: 364194
2019-06-24 16:16:12 +00:00
Matt Arsenault
e3a676e9ad CodeGen: Introduce a class for registers
Avoids using a plain unsigned for registers throughoug codegen.
Doesn't attempt to change every register use, just something a little
more than the set needed to build after changing the return type of
MachineOperand::getReg().

llvm-svn: 364191
2019-06-24 15:50:29 +00:00
Petar Avramovic
efcd3c0009 [MIPS GlobalISel] Handle position independent code
Handle position independent code for MIPS32.
When callee is global address, lower call will emit callee
as G_GLOBAL_VALUE and add target flag if needed.
Support $gp in getRegBankFromRegClass().
Select G_GLOBAL_VALUE, specially handle case when
there are target flags attached by lowerCall.

Differential Revision: https://reviews.llvm.org/D62589

llvm-svn: 362210
2019-05-31 08:27:06 +00:00
Petar Avramovic
f4a6dd28b6 [MIPS GlobalISel] Lower call for callee that is register
Lower call for callee that is register for MIPS32.
Register should contain callee function address.

Differential Revision: https://reviews.llvm.org/D62585

llvm-svn: 362204
2019-05-31 08:06:17 +00:00
Petar Avramovic
5a457e08f6 [MIPS GlobalISel] Lower float and double arguments in registers
Lower float and double arguments in registers for MIPS32.
When float/double argument is passed through gpr registers
select appropriate move instruction.

Differential Revision: https://reviews.llvm.org/D59642

llvm-svn: 356882
2019-03-25 11:23:41 +00:00
Matt Arsenault
2a64598ef2 GlobalISel: Fix creating MMOs with align 0
llvm-svn: 352712
2019-01-31 01:38:47 +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
Petar Avramovic
2624c8db68 [MIPS GlobalISel] Set operand order for G_MERGE and G_UNMERGE
Set operands order for G_MERGE_VALUES and G_UNMERGE_VALUES so
that least significant bits always go first, regardless of endianness.

Differential Revision: https://reviews.llvm.org/D54098

llvm-svn: 346305
2018-11-07 11:45:43 +00:00