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 e

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

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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 o

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.

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GlobalISel: Use LLT in call lowering callbacks

This preserves the memory type so the lowerings can rely on them.

GlobalISel: Split ValueHandler into assignment and emission classes

Currently the ValueHandler handles both selecting the type and
location for arguments, as well as inserting instructions needed to

GlobalISel: Split ValueHandler into assignment and emission classes

Currently the ValueHandler handles both selecting the type and
location for arguments, as well as inserting instructions needed to
handle them. Split this so that the determination of the argument
handling is independent of the function state. Currently the checks
for tail call compatibility do not follow the full assignment logic,
so it misses cases where arguments require nontrivial legalization.

This should help avoid targets ending up in a buggy state where the
argument evaluation may change in different contexts.

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X86/GlobalISel: Use generic version of splitToValueTypes

The custom insert of an unmerge and the callback weirdness should be
unnecessary. Since handleAssignments should now use
getRegisterTypeForCa

X86/GlobalISel: Use generic version of splitToValueTypes

The custom insert of an unmerge and the callback weirdness should be
unnecessary. Since handleAssignments should now use
getRegisterTypeForCalling conv as SelectionDAG builder would, this
should now just be able to use the generic code. X86-32 relies on the
generated CCAssignFns not seeing illegal types and sharing code with
x86_64, so i64 values would incorrectly be assigned to 64-bit
registers.

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GlobalISel: Use DAG call lowering infrastructure in a more compatible way

Unfortunately the current call lowering code is built on top of the
legacy MVT/DAG based code. However, GlobalISel was not u

GlobalISel: Use DAG call lowering infrastructure in a more compatible way

Unfortunately the current call lowering code is built on top of the
legacy MVT/DAG based code. However, GlobalISel was not using it the
same way. In short, the DAG passes legalized types to the assignment
function, and GlobalISel was passing the original raw type if it was
simple.

I do believe the DAG lowering is conceptually broken since it requires
picking a type up front before knowing how/where the value will be
passed. This ends up being a problem for AArch64, which wants to pass
i1/i8/i16 values as a different size if passed on the stack or in
registers.

The argument type decision is split across 3 different places which is
hard to follow. SelectionDAG builder uses
getRegisterTypeForCallingConv to pick a legal type, tablegen gives the
illusion of controlling the type, and the target may have additional
hacks in the C++ part of the call lowering. AArch64 hacks around this
by not using the standard AnalyzeFormalArguments and special casing
i1/i8/i16 by looking at the underlying type of the original IR
argument.

I believe people have generally assumed the calling convention code is
processing the original types, and I've discovered a number of dead
paths in several targets.

x86 actually relies on the opposite behavior from AArch64, and relies
on x86_32 and x86_64 sharing calling convention code where the 64-bit
cases implicitly do not work on x86_32 due to using the pre-legalized
types.

AMDGPU targets without legal i16/f16 have always used a broken ABI
that promotes to i32/f32. GlobalISel accidentally fixed this to be the
ABI we should have, but this fixes it so we're using the worse ABI
that is compatible with the DAG. Ideally we would fix the DAG to match
the old GlobalISel behavior, but I don't wish to fight that battle.

A new native GlobalISel call lowering framework should let the target
process the incoming types directly.

CCValAssigns select a "ValVT" and "LocVT" but the meanings of these
aren't entirely clear. Different targets don't use them consistently,
even within their own call lowering code. My current belief is the
intent was "ValVT" is supposed to be the legalized value type to use
in the end, and and LocVT was supposed to be the ABI passed type
(which is also legalized).

With the default CCState::Analyze functions always passing the same
type for these arguments, these only differ when the TableGen part of
the lowering decide to promote the type from one legal type to
another. AArch64's i1/i8/i16 hack ends up inverting the meanings of
these values, so I had to add an additional hack to let the target
interpret how large the argument memory is.

Since targets don't consistently interpret ValVT and LocVT, this
doesn't produce quite equivalent code to the initial DAG
lowerings. I've opted to consistently interpret LocVT as the in-memory
size for stack passed values, and ValVT as the register type to assign
from that memory. We therefore produce extending loads directly out of
the IRTranslator, whereas the DAG would emit regular loads of smaller
values. This will also produce loads/stores that are wider than the
argument value if the allocated stack slot is larger (and there will
be undef padding bytes). If we had the optimizations to reduce
load/stores based on truncated values, this wouldn't produce a
different end result.

Since ValVT/LocVT are more consistently interpreted, we now will emit
more G_BITCASTS as requested by the CCAssignFn. For example AArch64
was directly assigning types to some physical vector registers which
according to the tablegen spec should have been casted to a vector
with a different element type.

This also moves the responsibility for inserting
G_ASSERT_SEXT/G_ASSERT_ZEXT from the target ValueHandlers into the
generic code, which is closer to how SelectionDAGBuilder works.

I had to xfail an x86 test since I don't see a quick way to fix it
right now (I filed bug 50035 for this). It's broken independently of
this change, and only triggers since now we end up with more ands
which hit the improperly handled selection pattern.

I also observed that FP arguments that need promotion (e.g. f16 passed
as f32) are broken, and use regular G_TRUNC and G_ANYEXT.

TLDR; the current call lowering infrastructure is bad and nobody has
ever understood how it chooses types.

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X86/GlobalISel: Rely on default assignValueToReg

The resulting output is semantically closer to what the DAG emits and
is more compatible with the existing CCAssignFns.

The returns of f32 in f80 ar

X86/GlobalISel: Rely on default assignValueToReg

The resulting output is semantically closer to what the DAG emits and
is more compatible with the existing CCAssignFns.

The returns of f32 in f80 are clearly broken, but they were broken
before when using G_ANYEXT to go from f32 to f80.

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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.

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).

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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 s

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.

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GlobalISel: Fix using wrong calling convention for callees

This was taking the calling convention from the parent function,
instead of the callee. Avoids regressions in a future patch when the
calle

GlobalISel: Fix using wrong calling convention for callees

This was taking the calling convention from the parent function,
instead of the callee. Avoids regressions in a future patch when the
caller and callee have different type breakdowns.

For some reason AArch64's lowerFormalArguments seems to intentionally
ignore the parent isVarArg.

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[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 s

[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

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X86: Correcting X86OutgoingValueHandler typo (NFC)

https://reviews.llvm.org/D92631

[X86] assignValueToReg - fix Wshadow warning. NFCI.

X86OutgoingValueHandler already has a MIB member

X86CallLowering.cpp - improve auto const/pointer/reference qualifiers. NFCI.

Fix clang-tidy warnings by ensuring auto variables are more cleanly qualified, or just avoid auto entirely.

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 goin

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.

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[Alignment][NFC] Transition to inferAlignFromPtrInfo

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/

[Alignment][NFC] Transition to inferAlignFromPtrInfo

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, jvesely, nhaehnle, hiraditya, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77120

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[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/llv

[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

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GlobalISel: Set alignment on function argument stack load/store

[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,

[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

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[CodeGen] Make use of MachineInstrBuilder::getReg

Reviewers: arsenm

Subscribers: wdng, hiraditya, Petar.Avramovic, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73262

[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

[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

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[GISel][CallLowering] Make isIncomingArgumentHandler a pure virtual method

The default implementation of isIncomingArgumentHandler could lead
to generating incorrect code.
Make it a pure virtual met

[GISel][CallLowering] Make isIncomingArgumentHandler a pure virtual method

The default implementation of isIncomingArgumentHandler could lead
to generating incorrect code.
Make it a pure virtual method, so that targets know they have to
override it to produce correct code.

NFC

Differential Revision: https://reviews.llvm.org/D69187

llvm-svn: 375277

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[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 gene

[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

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Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVM

Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Re

Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVM

Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).

Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor

Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&

Depends on D65919

Reviewers: arsenm, bogner, craig.topper, RKSimon

Reviewed By: arsenm

Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65962

llvm-svn: 369041

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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

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

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