Commit Graph

1567 Commits

Author SHA1 Message Date
Craig Topper 844e94a502 [SelectionDAGBuilder] Remove Unnecessary FastMathFlags temporary. Use SDNodeFlags instead. NFCI
This was a missed simplication in D87200
2020-09-08 15:50:12 -07:00
Craig Topper b1e68f885b [SelectionDAGBuilder] Pass fast math flags to getNode calls rather than trying to set them after the fact.:
This removes the after the fact FMF handling from D46854 in favor of passing fast math flags to getNode. This should be a superset of D87130.

This required adding a SDNodeFlags to SelectionDAG::getSetCC.

Now we manage to contant fold some stuff undefs during the
initial getNode that we don't do in later DAG combines.

Differential Revision: https://reviews.llvm.org/D87200
2020-09-08 15:27:21 -07:00
Jonas Paulsson 714ceefad9 [SelectionDAG] Always intersect SDNode flags during getNode() node memoization.
Previously SDNodeFlags::instersectWith(Flags) would do nothing if Flags was
in an undefined state, which is very bad given that this is the default when
getNode() is called without passing an explicit SDNodeFlags argument.

This meant that if an already existing and reused node had a flag which the
second caller to getNode() did not set, that flag would remain uncleared.

This was exposed by https://bugs.llvm.org/show_bug.cgi?id=47092, where an NSW
flag was incorrectly set on an add instruction (which did in fact overflow in
one of the two original contexts), so when SystemZElimCompare removed the
compare with 0 trusting that flag, wrong-code resulted.

There is more that needs to be done in this area as discussed here:

Differential Revision: https://reviews.llvm.org/D86871

Review: Ulrich Weigand, Sanjay Patel
2020-09-05 10:30:38 +02:00
David Sherwood f4257c5832 [SVE] Make ElementCount members private
This patch changes ElementCount so that the Min and Scalable
members are now private and can only be accessed via the get
functions getKnownMinValue() and isScalable(). In addition I've
added some other member functions for more commonly used operations.
Hopefully this makes the class more useful and will reduce the
need for calling getKnownMinValue().

Differential Revision: https://reviews.llvm.org/D86065
2020-08-28 14:43:53 +01:00
Lucas Prates 3d943bcd22 [CodeGen] Properly propagating Calling Convention information when lowering vector arguments
When joining the legal parts of vector arguments into its original value
during the lower of Formal Arguments in SelectionDAGBuilder, the Calling
Convention information was not being propagated for the handling of each
individual parts. The same did not happen when lowering calls, causing a
mismatch.

This patch fixes the issue by properly propagating the Calling
Convention details.

This fixes Bugzilla #47001.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D86715
2020-08-27 17:01:10 +01:00
aartbik 72305a08ff [llvm] [DAG] Fix bug in llvm.get.active.lane.mask lowering
This intrinsic only accepted proper machine vector lengths.
Fixed by this change. With unit tests.

https://bugs.llvm.org/show_bug.cgi?id=47299

Reviewed By: SjoerdMeijer

Differential Revision: https://reviews.llvm.org/D86585
2020-08-26 10:16:31 -07:00
Sjoerd Meijer 39522b1e10 [SelectionDAG] Legalize intrinsic get.active.lane.mask
This adapts legalization of intrinsic get.active.lane.mask to the new semantics
as described in D86147. Because the second argument is now the loop tripcount,
we legalize this intrinsic to an 'icmp ULT' instead of an ULE when it was the
backedge-taken count.

Differential Revision: https://reviews.llvm.org/D86302
2020-08-25 15:00:10 +01:00
Jay Foad 0819a6416f [SelectionDAG] Better legalization for FSHL and FSHR
In SelectionDAGBuilder always translate the fshl and fshr intrinsics to
FSHL and FSHR (or ROTL and ROTR) instead of lowering them to shifts and
ORs. Improve the legalization of FSHL and FSHR to avoid code quality
regressions.

Differential Revision: https://reviews.llvm.org/D77152
2020-08-21 10:32:49 +01:00
Mehdi Amini a407ec9b6d Revert "Revert "[NFC][llvm] Make the contructors of `ElementCount` private.""
Was reverted because MLIR/Flang builds were broken, these APIs have been
fixed in the meantime.
2020-08-19 17:26:36 +00:00
Mehdi Amini 4fc56d70aa Revert "[NFC][llvm] Make the contructors of `ElementCount` private."
This reverts commit 264afb9e6a.
(and dependent 6b742cc48 and fc53bd610f)

MLIR/Flang are broken.
2020-08-19 17:21:37 +00:00
Francesco Petrogalli 264afb9e6a [NFC][llvm] Make the contructors of `ElementCount` private.
Differential Revision: https://reviews.llvm.org/D86120
2020-08-19 16:26:44 +00:00
Kerry McLaughlin 85c7e89f3b [CodeGen] Refactor getMemBasePlusOffset & getObjectPtrOffset to accept a TypeSize
Changes the Offset arguments to both functions from int64_t to TypeSize
& updates all uses of the functions to create the offset using TypeSize::Fixed()

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D85220
2020-08-11 12:17:10 +01:00
Bevin Hansson 5de6c56f7e [Intrinsic] Add sshl.sat/ushl.sat, saturated shift intrinsics.
Summary:
This patch adds two intrinsics, llvm.sshl.sat and llvm.ushl.sat,
which perform signed and unsigned saturating left shift,
respectively.

These are useful for implementing the Embedded-C fixed point
support in Clang, originally discussed in
http://lists.llvm.org/pipermail/llvm-dev/2018-August/125433.html
and
http://lists.llvm.org/pipermail/cfe-dev/2018-May/058019.html

Reviewers: leonardchan, craig.topper, bjope, jdoerfert

Subscribers: hiraditya, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83216
2020-08-07 15:09:24 +02:00
Jay Foad 28e322ea93 [PowerPC] Custom lowering for funnel shifts
The custom lowering saves an instruction over the generic expansion, by
taking advantage of the fact that PowerPC shift instructions are well
defined in the shift-by-bitwidth case.

Differential Revision: https://reviews.llvm.org/D83948
2020-08-04 16:30:49 +01:00
Cameron McInally 31c7a2fd5c [FPEnv] Don't transform FSUB(-0,X)->FNEG(X) in SelectionDAGBuilder.
This patch stops unconditionally transforming FSUB(-0,X) into an FNEG(X) while building the DAG. There is also one small change to handle the new FSUB(-0,X) similarly to FNEG(X) in the AMDGPU backend.

Differential Revision: https://reviews.llvm.org/D84056
2020-08-03 10:22:25 -05:00
Matt Arsenault 57bd64ff84 Support addrspacecast initializers with isNoopAddrSpaceCast
Moves isNoopAddrSpaceCast to the TargetMachine. It logically belongs
with the DataLayout.
2020-07-31 10:42:43 -04:00
Vitaly Buka b0eb40ca39 [NFC] Remove unused GetUnderlyingObject paramenter
Depends on D84617.

Differential Revision: https://reviews.llvm.org/D84621
2020-07-31 02:10:03 -07:00
Vitaly Buka 89051ebace [NFC] GetUnderlyingObject -> getUnderlyingObject
I am going to touch them in the next patch anyway
2020-07-30 21:08:24 -07:00
Jon Roelofs afae6d97fa [SelectionDAG] Fix lowering of vector geps
This fixes an assertion failure that was being triggered in
SelectionDAG::getZeroExtendInReg(), where it was trying to extend the <2xi32>
to i64 (which should have been <2xi64>).

Fixes: rdar://66016901

Differential Revision: https://reviews.llvm.org/D84884
2020-07-30 14:56:53 -06:00
Nikita Popov deb4bb2b3a [IR] Add min/max/abs intrinsics
This adds the llvm.abs(), llvm.umin(), llvm.umax(), llvm.smin(),
and llvm.smax() intrinsics specified in D81829. For SelectionDAG,
the ISD opcodes and all the legalization and lowering already exist,
so this just wires them up to the intrinsic in the SDAG builder and
adds rudimentary tests. For GlobalISel only the min/max intrinsics
are wired up, as llvm.abs() will require the addition of a G_ABS op,
and corresponding legalization support.

Differential Revision: https://reviews.llvm.org/D84125
2020-07-23 20:56:19 +02:00
Simon Pilgrim fa95688237 SelectionDAGBuilder.cpp - remove duplicate includes that already exist in SelectionDAGBuilder.h. NFC. 2020-07-22 14:19:41 +01:00
Matt Arsenault f659c44016 CodeGen: Add support for lowering byref attribute 2020-07-21 17:38:15 -04:00
Matt Arsenault 023883a834 IR: Rename Argument::hasPassPointeeByValueAttr to prepare for byref
When the byref attribute is added, there will need to be two similar
functions for the existing cases which have an associate value copy,
and byref which does not. Most, but not all of the existing uses will
use the existing version.

The associated size function added by D82679 also needs to
contextually differ, and will help eliminate a few places still
relying on pointee element types.
2020-07-16 13:50:49 -04:00
Tim Northover 5165b2b5fd AArch64+ARM: make LLVM consider system registers volatile.
Some of the system registers readable on AArch64 and ARM platforms
return different values with each read (for example a timer counter),
these shouldn't be hoisted outside loops or otherwise interfered with,
but the normal @llvm.read_register intrinsic is only considered to read
memory.

This introduces a separate @llvm.read_volatile_register intrinsic and
maps all system-registers on ARM platforms to use it for the
__builtin_arm_rsr calls. Registers declared with asm("r9") or similar
are unaffected.
2020-07-15 09:47:36 +01:00
Christopher Tetreault ff5b9a7b3b [SVE] Remove calls to VectorType::getNumElements from CodeGen
Reviewers: efriedma, fpetrogalli, sdesmalen, RKSimon, arsenm

Reviewed By: RKSimon

Subscribers: wdng, tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D82210
2020-07-09 12:43:36 -07:00
Heejin Ahn 7e6793aa33 [WebAssembly] Generate unreachable after __stack_chk_fail
`__stack_chk_fail` does not return, but `unreachable` was not generated
following `call __stack_chk_fail`. This had a possibility to generate an
invalid binary for functions with a return type, because
`__stack_chk_fail`'s return type is void and `call __stack_chk_fail` can
be the last instruction in the function whose return type is non-void.
Generating `unreachable` after it makes sure CFGStackify's
`fixEndsAtEndOfFunction` handles it correctly.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D83277
2020-07-08 01:02:05 -07:00
David Sherwood c061e56e88 [CodeGen] Fix warnings in sve-vector-splat.ll and sve-trunc.ll
This patch fixes all remaining warnings in:

  llvm/test/CodeGen/AArch64/sve-trunc.ll
  llvm/test/CodeGen/AArch64/sve-vector-splat.ll

I hit some warnings related to getCopyPartsToVector. I fixed two
issues:

1. In widenVectorToPartType() we assumed that we'd always be
using BUILD_VECTOR nodes to expand from one vector type to another,
which is incorrect for scalable vector types. I've fixed this for now
by simply bailing out immediately for scalable vectors.
2. In getCopyToPartsVector() I've changed the code to compare
the element counts of different types.

Differential Revision: https://reviews.llvm.org/D83028
2020-07-07 09:21:47 +01:00
Guillaume Chatelet 87e2751cf0 [Alignment][NFC] Use proper getter to retrieve alignment from ConstantInt and ConstantSDNode
This 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

Differential Revision: https://reviews.llvm.org/D83082
2020-07-03 08:06:43 +00:00
Sanjay Patel bc110de78a [SelectionDAG] don't split branch on logic-of-vector-compares
SelectionDAGBuilder converts logic-of-compares into multiple branches based
on a boolean TLI setting in isJumpExpensive(). But that probably never
considered the pattern of extracted bools from a vector compare - it seems
unlikely that we would want to turn vector logic into control-flow.

The motivating x86 reduction case is shown in PR44565:
https://bugs.llvm.org/show_bug.cgi?id=44565
...and that test shows the expected improvement from using pmovmsk codegen.

For AArch64, I modified the test to include an extra op because the simpler
test gets transformed by a codegen invocation of SimplifyCFG.

Differential Revision: https://reviews.llvm.org/D82602
2020-07-02 17:05:24 -04:00
David Sherwood c7df35d2b2 [CodeGen] Fix warnings in getCopyToPartsVector
Whilst trying to assemble the following test:

  clang/test/CodeGen/aarch64-sve-intrinsics/acle_sve_set2.c

I discovered we were hitting some warnings about possible invalid
calls to getVectorNumElements() in getCopyToPartsVector(). I've
tried to fix these by using ElementCount types where possible and
I've made the assumption that we don't support using a fixed width
vector to copy parts of a scalable vector, and vice versa. Looking
at how the copy is implemented I think that's the right thing for
now.

Differential Revision: https://reviews.llvm.org/D82744
2020-07-02 09:08:20 +01:00
James Y Knight 4b0aa5724f Change the INLINEASM_BR MachineInstr to be a non-terminating instruction.
Before this instruction supported output values, it fit fairly
naturally as a terminator. However, being a terminator while also
supporting outputs causes some trouble, as the physreg->vreg COPY
operations cannot be in the same block.

Modeling it as a non-terminator allows it to be handled the same way
as invoke is handled already.

Most of the changes here were created by auditing all the existing
users of MachineBasicBlock::isEHPad() and
MachineBasicBlock::hasEHPadSuccessor(), and adding calls to
isInlineAsmBrIndirectTarget or mayHaveInlineAsmBr, as appropriate.

Reviewed By: nickdesaulniers, void

Differential Revision: https://reviews.llvm.org/D79794
2020-07-01 12:51:50 -04:00
Guillaume Chatelet d3085c2501 [Alignment][NFC] Transition and simplify calls to DL::getABITypeAlignment
This 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

Differential Revision: https://reviews.llvm.org/D82956
2020-07-01 14:31:56 +00:00
Guillaume Chatelet 28de229bc6 [Alignment][NFC] Migrate MachineFrameInfo::CreateStackObject to Align
This 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

Differential Revision: https://reviews.llvm.org/D82894
2020-07-01 07:28:11 +00:00
Sjoerd Meijer 243a5329d4 [SelectionDAG] Lower @llvm.get.active.lane.mask to setcc
This lowers intrinsic @llvm.get.active.lane.mask to a setcc node, i.e. an icmp
ule, and creates vectors for its 2 arguments on which the comparison is
performed.

Differential Revision: https://reviews.llvm.org/D82292
2020-06-26 07:46:38 +01:00
Michael Liao b1360caa82 [SDAG] Add new AssertAlign ISD node.
Summary:
- AssertAlign node records the guaranteed alignment on its source node,
  where these alignments are retrieved from alignment attributes in LLVM
  IR. These tracked alignments could help DAG combining and lowering
  generating efficient code.
- In this patch, the basic support of AssertAlign node is added. So far,
  we only generate AssertAlign nodes on return values from intrinsic
  calls.
- Addressing selection in AMDGPU is revised accordingly to capture the
  new (base + offset) patterns.

Reviewers: arsenm, bogner

Subscribers: jvesely, wdng, nhaehnle, tpr, hiraditya, kerbowa, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81711
2020-06-23 00:51:11 -04:00
Lucas Prates a255931c40 [ARM] Supporting lowering of half-precision FP arguments and returns in AArch32's backend
Summary:
Half-precision floating point arguments and returns are currently
promoted to either float or int32 in clang's CodeGen and there's
no existing support for the lowering of `half` arguments and returns
from IR in AArch32's backend.

Such frontend coercions, implemented as coercion through memory
in clang, can cause a series of issues in argument lowering, as causing
arguments to be stored on the wrong bits on big-endian architectures
and incurring in missing overflow detections in the return of certain
functions.

This patch introduces the handling of half-precision arguments and returns in
the backend using the actual "half" type on the IR. Using the "half"
type the backend is able to properly enforce the AAPCS' directions for
those arguments, making sure they are stored on the proper bits of the
registers and performing the necessary floating point convertions.

Reviewers: rjmccall, olista01, asl, efriedma, ostannard, SjoerdMeijer

Reviewed By: ostannard

Subscribers: stuij, hiraditya, dmgreen, llvm-commits, chill, dnsampaio, danielkiss, kristof.beyls, cfe-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D75169
2020-06-18 13:15:13 +01:00
Simon Wallis 4dba59689d [ARM] prologue instructions emitted for naked function with >64 byte argument
Summary:

The naked function attribute is meant to suppress all function
prologue/epilogue instructions.

On ARM, some are still emitted if an argument greater than 64 bytes in size
(the threshold for using the byval attribute in IR) is passed partially
in registers.

Perform the check for Attribute::Naked and early exit in
SelectionDAGISel::LowerArguments().

Checking in ARMFrameLowering::determineCalleeSaves() is too late.

A test case is included.

Reviewers: llvm-commits, olista01, danielkiss

Reviewed By: danielkiss

Subscribers: kristof.beyls, hiraditya, danielkiss

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80715

Change-Id: Icedecf2a4ad31bc3c35ab0df7489a9d346e1f7cc
2020-06-09 11:33:03 +01:00
Christopher Tetreault caa2fddce7 [SVE] Eliminate calls to default-false VectorType::get() from CodeGen
Reviewers: efriedma, c-rhodes, david-arm, spatel, craig.topper, aqjune, paquette, arsenm, gchatelet

Reviewed By: spatel, gchatelet

Subscribers: wdng, tschuett, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80313
2020-06-08 10:26:10 -07:00
Philip Reames 4c735439fd [Statepoint] Migrate a few tests to gc-live bundle format and fix assert
The assert was missed in 0e7c7705, migrating the test revealed the problem.
2020-06-04 18:15:58 -07:00
Henry Kao c57e41c000 [CodeGen][SVE] Replace deprecated calls in getCopyFromPartsVector()
Summary: Replaced getVectorNumElements() with getVectorElementCount(). Added operator overloads for class ElementCount. Fixes warning in several AArch64 unit tests.

Reviewers: sdesmalen, kmclaughlin, dancgr, efriedma, each, andwar, rengolin

Reviewed By: efriedma

Subscribers: tschuett, kristof.beyls, hiraditya, rkruppe, psnobl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80826
2020-06-03 11:20:02 -04:00
David Sherwood d8a78889f6 [CodeGen] Fix warning in visitShuffleVector
Make sure we only ask for the number of elements after we've
bailed out for scalable vectors.

Differential revision: https://reviews.llvm.org/D80632
2020-05-29 17:09:59 +01:00
Philip Reames 98a87c65a3 [Statepoint] Reduce scope of usage of ImmutableStatepoint
Can't quite fully remove it yet as some more items need sunk the GCStatepointInst class from the wrapper, but we can at least reduce scope.
2020-05-27 18:57:42 -07:00
Philip Reames 87bea912c2 [Statepoint] Replace uses of isX functions with idiomatic isa<X>
Now that all of the statepoint related routines have classes with isa support, let's cleanup.

I'm leaving the (dead) utitilities in tree for a few days so that I can do the same cleanup downstream without breakage.
2020-05-27 18:32:28 -07:00
Philip Reames 1af3705c7f Start migrating away from statepoint's inline length prefixed argument bundles
In the current statepoint design, we have four distinct groups of operands to the call: call args, gc transition args, deopt args, and gc args. This format prexisted the support in IR for operand bundles and was in fact one of the inspirations for the extension. However, we never went back and rearchitected statepoints to fully leverage bundles.

This change is the first in a small sequence to do so. All this does is extend the SelectionDAG lowering code to allow deopt and gc transition operands to be specified in either inline argument bundles or operand bundles.

Differential Revision: https://reviews.llvm.org/D8059
2020-05-27 09:16:10 -07:00
Serge Pavlov 4d20e31f73 [FPEnv] Intrinsic llvm.roundeven
This intrinsic implements IEEE-754 operation roundToIntegralTiesToEven,
and performs rounding to the nearest integer value, rounding halfway
cases to even. The intrinsic represents the missed case of IEEE-754
rounding operations and now llvm provides full support of the rounding
operations defined by the standard.

Differential Revision: https://reviews.llvm.org/D75670
2020-05-26 19:24:58 +07:00
Craig Topper 7392820f98 [Align] Remove operations on MaybeAlign that asserted that it had a defined value.
If the caller needs to reponsible for making sure the MaybeAlign
has a value, then we should just make the caller convert it to an Align
with operator*.

I explicitly deleted the relational comparison operators that
were being inherited from Optional. It's unclear what the meaning
of two MaybeAligns were one is defined and the other isn't
should be. So make the caller reponsible for defining the behavior.

I left the ==/!= operators from Optional. But now that exposed a
weird quirk that ==/!= between Align and MaybeAlign required the
MaybeAlign to be defined. But now we use the operator== from
Optional that takes an Optional and the Value.

Differential Revision: https://reviews.llvm.org/D80455
2020-05-22 21:54:28 -07:00
Arthur Eubanks 8a88755610 Reland [X86] Codegen for preallocated
See https://reviews.llvm.org/D74651 for the preallocated IR constructs
and LangRef changes.

In X86TargetLowering::LowerCall(), if a call is preallocated, record
each argument's offset from the stack pointer and the total stack
adjustment. Associate the call Value with an integer index. Store the
info in X86MachineFunctionInfo with the integer index as the key.

This adds two new target independent ISDOpcodes and two new target
dependent Opcodes corresponding to @llvm.call.preallocated.{setup,arg}.

The setup ISelDAG node takes in a chain and outputs a chain and a
SrcValue of the preallocated call Value. It is lowered to a target
dependent node with the SrcValue replaced with the integer index key by
looking in X86MachineFunctionInfo. In
X86TargetLowering::EmitInstrWithCustomInserter() this is lowered to an
%esp adjustment, the exact amount determined by looking in
X86MachineFunctionInfo with the integer index key.

The arg ISelDAG node takes in a chain, a SrcValue of the preallocated
call Value, and the arg index int constant. It produces a chain and the
pointer fo the arg. It is lowered to a target dependent node with the
SrcValue replaced with the integer index key by looking in
X86MachineFunctionInfo. In
X86TargetLowering::EmitInstrWithCustomInserter() this is lowered to a
lea of the stack pointer plus an offset determined by looking in
X86MachineFunctionInfo with the integer index key.

Force any function containing a preallocated call to use the frame
pointer.

Does not yet handle a setup without a call, or a conditional call.
Does not yet handle musttail. That requires a LangRef change first.

Tried to look at all references to inalloca and see if they apply to
preallocated. I've made preallocated versions of tests testing inalloca
whenever possible and when they make sense (e.g. not alloca related,
inalloca edge cases).

Aside from the tests added here, I checked that this codegen produces
correct code for something like

```
struct A {
        A();
        A(A&&);
        ~A();
};

void bar() {
        foo(foo(foo(foo(foo(A(), 4), 5), 6), 7), 8);
}
```

by replacing the inalloca version of the .ll file with the appropriate
preallocated code. Running the executable produces the same results as
using the current inalloca implementation.

Reverted due to unexpectedly passing tests, added REQUIRES: asserts for reland.

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77689
2020-05-20 11:25:44 -07:00
Arthur Eubanks b8cbff51d3 Revert "[X86] Codegen for preallocated"
This reverts commit 810567dc69.

Some tests are unexpectedly passing
2020-05-20 10:04:55 -07:00
Arthur Eubanks 810567dc69 [X86] Codegen for preallocated
See https://reviews.llvm.org/D74651 for the preallocated IR constructs
and LangRef changes.

In X86TargetLowering::LowerCall(), if a call is preallocated, record
each argument's offset from the stack pointer and the total stack
adjustment. Associate the call Value with an integer index. Store the
info in X86MachineFunctionInfo with the integer index as the key.

This adds two new target independent ISDOpcodes and two new target
dependent Opcodes corresponding to @llvm.call.preallocated.{setup,arg}.

The setup ISelDAG node takes in a chain and outputs a chain and a
SrcValue of the preallocated call Value. It is lowered to a target
dependent node with the SrcValue replaced with the integer index key by
looking in X86MachineFunctionInfo. In
X86TargetLowering::EmitInstrWithCustomInserter() this is lowered to an
%esp adjustment, the exact amount determined by looking in
X86MachineFunctionInfo with the integer index key.

The arg ISelDAG node takes in a chain, a SrcValue of the preallocated
call Value, and the arg index int constant. It produces a chain and the
pointer fo the arg. It is lowered to a target dependent node with the
SrcValue replaced with the integer index key by looking in
X86MachineFunctionInfo. In
X86TargetLowering::EmitInstrWithCustomInserter() this is lowered to a
lea of the stack pointer plus an offset determined by looking in
X86MachineFunctionInfo with the integer index key.

Force any function containing a preallocated call to use the frame
pointer.

Does not yet handle a setup without a call, or a conditional call.
Does not yet handle musttail. That requires a LangRef change first.

Tried to look at all references to inalloca and see if they apply to
preallocated. I've made preallocated versions of tests testing inalloca
whenever possible and when they make sense (e.g. not alloca related,
inalloca edge cases).

Aside from the tests added here, I checked that this codegen produces
correct code for something like

```
struct A {
        A();
        A(A&&);
        ~A();
};

void bar() {
        foo(foo(foo(foo(foo(A(), 4), 5), 6), 7), 8);
}
```

by replacing the inalloca version of the .ll file with the appropriate
preallocated code. Running the executable produces the same results as
using the current inalloca implementation.

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77689
2020-05-20 09:20:38 -07:00
Matt Arsenault 3e315697ac DAG: Use correct pointer size for llvm.ptrmask
This was ignoring the address space, and would assert on address
spaces with a different size from the default.
2020-05-18 16:46:11 -04:00