Commit Graph

25440 Commits

Author SHA1 Message Date
Alex Lorenz afa75d7843 [macho] save the SDK version stored in module metadata into the version min and
build version load commands in the object file

This commit introduces a new metadata node called "SDK Version". It will be set
by the frontend to mark the platform SDK (macOS/iOS/etc) version which was used
during that particular compilation.
This node is used when machine code is emitted, by either saving the SDK version
into the appropriate macho load command (version min/build version), or by
emitting the assembly for these load commands with the SDK version specified as
well.
The assembly for both load commands is extended by allowing it to contain the
sdk_version X, Y [, Z] trailing directive to represent the SDK version
respectively.

rdar://45774000

Differential Revision: https://reviews.llvm.org/D55612

llvm-svn: 349119
2018-12-14 01:14:10 +00:00
Sanjay Patel 093ab45d4c [DAGCombiner] clean up visitEXTRACT_VECTOR_ELT
This isn't quite NFC, but I don't know how to expose
any outward diffs from these changes. Mostly, this
was confusing because it used 'VT' to refer to the
operand type rather the usual type of the input node.

There's also a large block at the end that is dedicated 
solely to matching loads, but that wasn't obvious. This
could probably be split up into separate functions to
make it easier to see. 

It's still not clear to me when we make certain transforms 
because the legality and constant conditions are 
intertwined in a way that might be improved.

llvm-svn: 349095
2018-12-14 00:09:08 +00:00
Francis Visoiu Mistrih 91e69d8a92 [MachO][TLOF] Add support for local symbols in the indirect symbol table
On 32-bit archs, before, we would assume that an indirect symbol will
never have local linkage. This can lead to miscompiles where the
symbol's value would be 0 and the linker would use that value, because
the indirect symbol table would contain the value
`INDIRECT_SYMBOL_LOCAL` for that specific symbol.

Differential Revision: https://reviews.llvm.org/D55573

llvm-svn: 349060
2018-12-13 17:23:30 +00:00
Sanjay Patel 791ae69afe [DAGCombiner] after simplifying demanded elements of vector operand of extract, revisit the extract; 2nd try
This is a retry of rL349051 (reverted at rL349056). I changed the check for dead-ness from
number of uses to an opcode test for DELETED_NODE based on existing similar code.

Differential Revision: https://reviews.llvm.org/D55655

llvm-svn: 349058
2018-12-13 17:05:01 +00:00
Sanjay Patel c56f5728ee revert rL349051: [DAGCombiner] after simplifying demanded elements of vector operand of extract, revisit the extract
This causes an address sanitizer bot failure:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/27187/steps/check-llvm%20asan/logs/stdio

llvm-svn: 349056
2018-12-13 16:32:44 +00:00
Sanjay Patel a7b115b392 [DAGCombiner] after simplifying demanded elements of vector operand of extract, revisit the extract
Differential Revision: https://reviews.llvm.org/D55655

llvm-svn: 349051
2018-12-13 15:44:26 +00:00
Daniel Sanders b51480ff3e [mir] Fix uninitialized variable in r349035 noticed by clang-atom-d525-fedora-rel and 3 other bots
llvm-svn: 349043
2018-12-13 15:05:27 +00:00
Daniel Sanders 9f3cf55e63 [mir] Serialize DILocation inline when not possible to use a metadata reference
Summary:
Sometimes MIR-level passes create DILocations that were not present in the
LLVM-IR. For example, it may merge two DILocations together to produce a
DILocation that points to line 0.

Previously, the address of these DILocations were printed which prevented the
MIR from being read back into LLVM. With this patch, DILocations will use
metadata references where possible and fall back on serializing them inline like so:
    MOV32mr %stack.0.x.addr, 1, _, 0, _, %0, debug-location !DILocation(line: 1, scope: !15)

Reviewers: aprantl, vsk, arphaman

Reviewed By: aprantl

Subscribers: probinson, llvm-commits

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D55243

llvm-svn: 349035
2018-12-13 14:25:27 +00:00
Simon Pilgrim ab973a45b9 [DAGCombine] Moved X86 rotate_amount % bitwidth == 0 early out to DAGCombiner
Remove common code from custom lowering (code is still safe if somehow a zero value gets used).

llvm-svn: 349028
2018-12-13 12:23:32 +00:00
Simon Pilgrim 77fc551d1a [TargetLowering] Add ISD::ROTL/ROTR vector expansion
Move existing rotation expansion code into TargetLowering and set it up for vectors as well.

Ideally this would share more of the funnel shift expansion, but we handle the shift amount modulo quite differently at the moment.

Begun removing x86 vector rotate custom lowering to use the expansion.

llvm-svn: 349025
2018-12-13 11:20:48 +00:00
Clement Courbet 76f4ae1092 [CodeGen] Allow mempcy/memset to generate small overlapping stores.
Summary:
All targets either just return false here or properly model `Fast`, so I
don't think there is any reason to prevent CodeGen from doing the right
thing here.

Subscribers: nemanjai, javed.absar, eraman, jsji, llvm-commits

Differential Revision: https://reviews.llvm.org/D55365

llvm-svn: 349016
2018-12-13 09:56:19 +00:00
Daniel Sanders d001e0e0f4 [globalisel] Add GISelChangeObserver::changingInstr()
Summary:
In addition to knowing that an instruction is changed. It's also useful to
know when it's about to change. For example, it might print the instruction so
you can track the changes in a debug log, it might remove it from some queue
while it's being worked on, or it might want to change several instructions as
a single transaction and act on all the changes at once.

Added changingInstr() to all existing uses of changedInstr()

Reviewers: aditya_nandakumar

Reviewed By: aditya_nandakumar

Subscribers: rovka, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D55623

llvm-svn: 348992
2018-12-12 23:48:13 +00:00
Daniel Sanders 91dfdd5734 [globalisel] Rename GISelChangeObserver's erasedInstr() to erasingInstr() and related nits. NFC
Summary:
There's little of interest that can be done to an already-erased instruction.
You can't inspect it, write it to a debug log, etc. It ought to be notification
that we're about to erase it. Rename the function to clarify the timing of the
event and reflect current usage.

Also fixed one case where we were trying to print an erased instruction.

Reviewers: aditya_nandakumar

Reviewed By: aditya_nandakumar

Subscribers: rovka, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D55611

llvm-svn: 348976
2018-12-12 21:32:01 +00:00
Simon Pilgrim eb508f8ccb [SelectionDAG] Add a generic isSplatValue function
This patch introduces a generic function to determine whether a given vector type is known to be a splat value for the specified demanded elements, recursing up the DAG looking for BUILD_VECTOR or VECTOR_SHUFFLE splat patterns.

It also keeps track of the elements that are known to be UNDEF - it returns true if all the demanded elements are UNDEF (as this may be useful under some circumstances), so this needs to be handled by the caller.

A wrapper variant is also provided that doesn't take the DemandedElts or UndefElts arguments for cases where we just want to know if the SDValue is a splat or not (with/without UNDEFS).

I had hoped to completely remove the X86 local version of this function, but I'm seeing some regressions in shift/rotate codegen that will take a little longer to fix and I hope to get this in sooner so I can continue work on PR38243 which needs more capable splat detection.

Differential Revision: https://reviews.llvm.org/D55426

llvm-svn: 348953
2018-12-12 18:32:29 +00:00
Simon Pilgrim f6c898e12f [TargetLowering] Add ISD::AND handling to SimplifyDemandedVectorElts
If either of the operand elements are zero then we know the result element is going to be zero (even if the other element is undef).

Differential Revision: https://reviews.llvm.org/D55558

llvm-svn: 348926
2018-12-12 13:43:07 +00:00
Leonard Chan 118e53fd63 [Intrinsic] Signed Fixed Point Multiplication Intrinsic
Add an intrinsic that takes 2 signed integers with the scale of them provided
as the third argument and performs fixed point multiplication on them.

This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.

Differential Revision: https://reviews.llvm.org/D54719

llvm-svn: 348912
2018-12-12 06:29:14 +00:00
Reid Kleckner 9571c806c5 [codeview] Look through typedefs in getCompleteTypeIndex
Summary:
Any time a symbol record, whether it's S_UDT, S_LOCAL, or S_[GL]DATA32,
references a record type, it should use the complete type index, even if
there's a typedef in the way.

Fixes the compiler part of PR39853.

Reviewers: zturner, aganea

Subscribers: hiraditya, arphaman, llvm-commits

Differential Revision: https://reviews.llvm.org/D55236

llvm-svn: 348902
2018-12-11 23:07:39 +00:00
Craig Topper 502865bddb [GISel] Add parentheses to an assert because gcc is mean.
llvm-svn: 348900
2018-12-11 22:07:06 +00:00
Jordan Rupprecht e833cd46eb Revert "debuginfo: Use symbol difference for CU length to simplify assembly reading/editing"
Temporarily reverts commit r348806 due to strange asm compilation issues in certain modes (combination of asan+cuda+other things). Will provide repro soon.

llvm-svn: 348898
2018-12-11 21:26:52 +00:00
Wolfgang Pieb ac874c48ca [Debuginfo] Prevent CodeGenPrepare from dropping debuginfo references.
This fixes PR39845. CodeGenPrepare employs a transactional model when 
performing optimizations, i.e. it changes the IR to attempt an optimization
and rolls back the change when it finds the change inadequate. It is during
the rollback that references to locals were dropped from debug value 
intrinsics. This patch reinstates debuginfo references during rollbacks.

Reviewers: aprantl, vsk

Differential Revision: https://reviews.llvm.org/D55396 

llvm-svn: 348896
2018-12-11 21:13:53 +00:00
Aditya Nandakumar 853a667812 [GISel]: Add MachineIRBuilder support for passing in Flags while building
https://reviews.llvm.org/D55516

Add the ability to pass in flags to buildInstr calls. Currently no
validation is performed but that can be easily performed based on the
opcode (if necessary).

Reviewed by: paquette.

llvm-svn: 348893
2018-12-11 20:04:40 +00:00
Clement Courbet 8b6434bbb9 Revert r348843 "[CodeGen] Allow mempcy/memset to generate small overlapping stores."
Breaks ARM/memcpy-inline.ll

llvm-svn: 348844
2018-12-11 13:38:43 +00:00
Clement Courbet 93b3445770 [CodeGen] Allow mempcy/memset to generate small overlapping stores.
Summary:
All targets either just return false here or properly model `Fast`, so I
don't think there is any reason to prevent CodeGen from doing the right
thing here.

Subscribers: nemanjai, javed.absar, eraman, jsji, llvm-commits

Differential Revision: https://reviews.llvm.org/D55365

llvm-svn: 348843
2018-12-11 13:15:56 +00:00
Simon Pilgrim f6371f5f23 [TargetLowering] Add ISD::EXTRACT_VECTOR_ELT support to SimplifyDemandedBits
Let SimplifyDemandedBits attempt to simplify all elements of a vector extraction.

Part of PR39689.

llvm-svn: 348839
2018-12-11 11:08:40 +00:00
Aditya Nandakumar cef44a2342 [GISel]: Refactor MachineIRBuilder to allow passing additional parameters to build Instrs
https://reviews.llvm.org/D55294

Previously MachineIRBuilder::buildInstr used to accept variadic
arguments for sources (which were either unsigned or
MachineInstrBuilder). While this worked well in common cases, it doesn't
allow us to build instructions that have multiple destinations.
Additionally passing in other optional parameters in the end (such as
flags) is not possible trivially. Also a trivial call such as

B.buildInstr(Opc, Reg1, Reg2, Reg3)
can be interpreted differently based on the opcode (2defs + 1 src for
unmerge vs 1 def + 2srcs).
This patch refactors the buildInstr to

buildInstr(Opc, ArrayRef<DstOps>, ArrayRef<SrcOps>)
where DstOps and SrcOps are typed unions that know how to add itself to
MachineInstrBuilder.
After this patch, most invocations would look like

B.buildInstr(Opc, {s32, DstReg}, {SrcRegs..., SrcMIBs..});
Now all the other calls (such as buildAdd, buildSub etc) forward to
buildInstr. It also makes it possible to build instructions with
multiple defs.
Additionally in a subsequent patch, we should make it possible to add
flags directly while building instructions.
Additionally, the main buildInstr method is now virtual and other
builders now only have to override buildInstr (for say constant
folding/cseing) is straightforward.

Also attached here (https://reviews.llvm.org/F7675680) is a clang-tidy
patch that should upgrade the API calls if necessary.

llvm-svn: 348815
2018-12-11 00:48:50 +00:00
David Blaikie dbe67c4f19 debuginfo: Use symbol difference for CU length to simplify assembly reading/editing
Mucking about simplifying a test case ( https://reviews.llvm.org/D55261 ) I stumbled across something I've hit before - that LLVM's (GCC's does too, FWIW) assembly output includes a hardcode length for a DWARF unit in its header. Instead we could emit a label difference - making the assembly easier to read/edit (though potentially at a slight (I haven't tried to observe it) performance cost of delaying/sinking the length computation into the MC layer).

Reviewers: JDevlieghere, probinson, ABataev

Differential Revision: https://reviews.llvm.org/D55281

llvm-svn: 348806
2018-12-10 22:44:48 +00:00
Amara Emerson 5ec146046c [GlobalISel] Restrict G_MERGE_VALUES capability and replace with new opcodes.
This patch restricts the capability of G_MERGE_VALUES, and uses the new
G_BUILD_VECTOR and G_CONCAT_VECTORS opcodes instead in the appropriate places.

This patch also includes AArch64 support for selecting G_BUILD_VECTOR of <4 x s32>
and <2 x s64> vectors.

Differential Revisions: https://reviews.llvm.org/D53629

llvm-svn: 348788
2018-12-10 18:44:58 +00:00
Simon Pilgrim fc2c9af99c [TargetLowering] Add UNDEF folding to SimplifyDemandedVectorElts
If all the demanded elements of the SimplifyDemandedVectorElts are known to be UNDEF, we can simplify to an ISD::UNDEF node.

Zero constant folding will be handled in a future patch - its a little trickier as we often have bitcasted zero values.

Differential Revision: https://reviews.llvm.org/D55511

llvm-svn: 348784
2018-12-10 18:29:46 +00:00
Simon Pilgrim c73a955370 [DAGCombiner] Remove unnecessary recursive DAGCombiner::visitINSERT_SUBVECTOR call.
As discussed on D55511, this caused an issue if the inner node deletes a node that the outer node depends upon. As it doesn't affect any lit-tests and I've only been able to expose this with the D55511 change I'm committing this now.

llvm-svn: 348781
2018-12-10 18:18:50 +00:00
Petr Pavlu 84e89ff06f [GlobalISel] Set stack protector index when translating Intrinsic::stackprotector
Record the stack protector index in MachineFrameInfo when translating
Intrinsic::stackprotector similarly as is done by SelectionDAG when
processing the same intrinsic.

Setting this index allows the Prologue/Epilogue Insertion to recognize
that the stack protection is enabled. The pass can then make sure that
the stack protector comes before local variables on the stack and
assigns potentially vulnerable objects first so they are close to the
stack protector slot.

Differential Revision: https://reviews.llvm.org/D55418

llvm-svn: 348761
2018-12-10 15:15:05 +00:00
Francis Visoiu Mistrih 753efe3584 [DAGCombiner] Use the result value type in visitCONCAT_VECTORS
This triggers an assert when combining concat_vectors of a bitcast of
merge_values.

With asserts disabled, it fails to select:
fatal error: error in backend: Cannot select: 0x7ff19d000e90: i32 = any_extend 0x7ff19d000ae8
  0x7ff19d000ae8: f64,ch = CopyFromReg 0x7ff19d000c20:1, Register:f64 %1
    0x7ff19d000b50: f64 = Register %1
In function: d

Differential Revision: https://reviews.llvm.org/D55507

llvm-svn: 348759
2018-12-10 14:31:34 +00:00
Jeremy Morse a06b163d5c [DebugInfo] Don't drop dbg.value's of nullptr
Currently, dbg.value's of "nullptr" are dropped when entering a SelectionDAG --
apparently just because of an oversight when recognising Values that are
constant (see PR39787). This patch adds ConstantPointerNull to the list of
constants that can be turned into DBG_VALUEs.

The matter of what bit-value a null pointer constant in LLVM has was raised
in this mailing list thread:

  http://lists.llvm.org/pipermail/llvm-dev/2018-December/128234.html

Where it transpires LLVM relies on (IR) null pointers being zero valued,
thus I've baked this assumption into the patch.

Differential Revision: https://reviews.llvm.org/D55227

llvm-svn: 348753
2018-12-10 12:04:08 +00:00
Jeremy Morse 045c67769d [DebugInfo] Emit undef DBG_VALUEs when SDNodes are optimised out
This is a fix for PR39896, where dbg.value's of SDNodes that have been
optimised out do not lead to "DBG_VALUE undef" instructions being created.
Such undef instructions are necessary to terminate earlier variable
ranges, otherwise variable values leak past the point where they're valid.

The "invalidated" flag of SDDbgValue is currently being abused to mean two
things:
 * The corresponding SDNode is now invalid
 * This SDDbgValue should not be emitted
Of which there are several legitimate combinations of meaning:
 * The SDNode has been invalidated and we should emit "DBG_VALUE undef"
 * The SDNode has been invalidated but the debug data was salvaged, don't
   emit anything for this SDDbgValue
 * This SDDbgValue has been emitted

This patch introduces distinct "Emitted" and "Invalidated" fields to the
SDDbgValue class, updates users accordingly, and generates "undef"
DBG_VALUEs for invalidated records. Awkwardly, there are circumstances
where we emit SDDbgValue's twice, specifically DebugInfo/X86/dbg-addr-dse.ll
which I've preserved.

Differential Revision: https://reviews.llvm.org/D55372

llvm-svn: 348751
2018-12-10 11:20:47 +00:00
Sanjay Patel e767bf4468 [DAGCombiner] re-enable truncation of binops
This is effectively re-committing the changes from:
rL347917 (D54640)
rL348195 (D55126)
...which were effectively reverted here:
rL348604
...because the code had a bug that could induce infinite looping
or eventual out-of-memory compilation.

The bug was that this code did not guard against transforming
opaque constants. More details are in the post-commit mailing
list thread for r347917. A reduced test for that is included
in the x86 bool-math.ll file. (I wasn't able to reduce a PPC
backend test for this, but it was almost the same pattern.)

Original commit message for r347917:

The motivating case for this is shown in:
https://bugs.llvm.org/show_bug.cgi?id=32023
and the corresponding rot16.ll regression tests.

Because x86 scalar shift amounts are i8 values, we can end up with trunc-binop-trunc
sequences that don't get folded in IR.

As the TODO comments suggest, there will be regressions if we extend this (for x86,
we mostly seem to be missing LEA opportunities, but there are likely vector folds
missing too). I think those should be considered existing bugs because this is the
same transform that we do as an IR canonicalization in instcombine. We just need
more tests to make those visible independent of this patch.

llvm-svn: 348706
2018-12-08 16:07:38 +00:00
Craig Topper b4c96f5a32 [SelectionDAG] Remove ISD::ADDC/ADDE from some undef handling code in getNode. NFCI
These nodes should have two results. A real VT and a Glue. But this code would have returned Undef which would only be a single result. But we're in the single result version of getNode so these opcodes should never be seen by this function anyway.

llvm-svn: 348670
2018-12-08 00:27:34 +00:00
Jessica Paquette cc4b6920b3 [GlobalISel] Add IR translation support for the @llvm.log10 intrinsic
This adds IR translation support for @llvm.log10 and updates relevant tests.

https://reviews.llvm.org/D55392

llvm-svn: 348657
2018-12-07 22:08:02 +00:00
Pete Cooper 782a490dfb Follow-up from r348441 to add the rest of the objc ARC intrinsics.
This adds the other intrinsics used by ARC and codegen's them to their respective runtime methods.

llvm-svn: 348646
2018-12-07 21:28:47 +00:00
Sanjay Patel bc47ff86fe [DAGCombiner] split trunc from extend in hoistLogicOpWithSameOpcodeHands; NFC
This duplicates several shared checks, but we need to split
this up to fix underlying bugs in smaller steps.

llvm-svn: 348627
2018-12-07 18:51:08 +00:00
Sanjay Patel 3af4ae9735 [DAGCombiner] disable truncation of binops by default
As discussed in the post-commit thread of r347917, this
transform is fighting with an existing transform causing
an infinite loop or out-of-memory, so this is effectively 
reverting r347917 and its follow-up r348195 while we
investigate the bug.

llvm-svn: 348604
2018-12-07 15:47:52 +00:00
Sanjay Patel bb796cd61c [DAGCombiner] remove explicit calls to AddToWorkList; NFCI
As noted in the post-commit thread for rL347917:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181203/608936.html
...we don't need to repeat these calls because the combiner does it automatically.

llvm-svn: 348597
2018-12-07 15:00:56 +00:00
Simon Pilgrim d498dee7a2 [SelectionDAG] Don't pass on DemandedElts when handling SCALAR_TO_VECTOR
Fixes an assertion:

llc: lib/CodeGen/SelectionDAG/SelectionDAG.cpp:2200: llvm::KnownBits llvm::SelectionDAG::computeKnownBits(llvm::SDValue, const llvm::APInt&, unsigned int) const: Assertion `(!Op.getValueType().isVector() || NumElts == Op.getValueType().getVectorNumElements()) && "Unexpected vector size"' failed.

Committed on behalf of: @pendingchaos (Rhys Perry)

Differential Revision: https://reviews.llvm.org/D55223

llvm-svn: 348574
2018-12-07 09:18:44 +00:00
Sanjay Patel c6441c8547 [DAGCombiner] use root SDLoc for all nodes created by logic fold
If this is not a valid way to assign an SDLoc, then we get this
wrong all over SDAG.

I don't know enough about the SDAG to explain this. IIUC, theoretically,
debug info is not supposed to affect codegen. But here it has clearly
affected 3 different targets, and the x86 change is an actual improvement.

llvm-svn: 348552
2018-12-07 00:01:57 +00:00
Sanjay Patel 86cb679851 [DAGCombiner] don't bother saving a SDLoc for a node that's dead; NFCI
We shouldn't care about the debug location for a node that
we're creating, but attaching the root of the pattern should
be the best effort. (If this is not true, then we are doing
it wrong all over the SDAG).

This is no-functional-change-intended, and there are no
regression test diffs...and that's what I expected. But
there's a similar line above this diff, where those
assumptions apparently do not hold.

llvm-svn: 348550
2018-12-06 23:53:58 +00:00
Sanjay Patel 276cef343c [DAGCombiner] more clean up in hoistLogicOpWithSameOpcodeHands(); NFC
This code can still misbehave.

llvm-svn: 348547
2018-12-06 23:39:28 +00:00
Sanjay Patel 70af85b0ac [DAGCombiner] don't group bswap with casts in logic hoisting fold
This was probably organized as it was because bswap is a unary op.
But that's where the similarity to the other opcodes ends. We should
not limit this transform to scalars, and we should not try it if
either input has other uses. This is another step towards trying to
clean this whole function up to prevent it from causing infinite loops
and memory explosions. 

Earlier commits in this series:
rL348501
rL348508
rL348518

llvm-svn: 348534
2018-12-06 22:10:44 +00:00
Sanjay Patel 03a3ef2a0c [DAGCombiner] reduce indent; NFC
Unlike some of the folds in hoistLogicOpWithSameOpcodeHands()
above this shuffle transform, this has the expected hasOneUse()
checks in place.

llvm-svn: 348523
2018-12-06 20:02:47 +00:00
Andrea Di Biagio 52a2bac583 [DagCombiner][X86] Simplify a ConcatVectors of a scalar_to_vector with undef.
This patch introduces a new DAGCombiner rule to simplify concat_vectors nodes:

concat_vectors( bitcast (scalar_to_vector %A), UNDEF)
    --> bitcast (scalar_to_vector %A)

This patch only partially addresses PR39257. In particular, it is enough to fix
one of the two problematic cases mentioned in PR39257. However, it is not enough
to fix the original test case posted by Craig; that particular case would
probably require a more complicated approach (and knowledge about used bits).

Before this patch, we used to generate the following code for function PR39257
(-mtriple=x86_64 , -mattr=+avx):

vmovsd  (%rdi), %xmm0           # xmm0 = mem[0],zero
vxorps  %xmm1, %xmm1, %xmm1
vblendps        $3, %xmm0, %xmm1, %xmm0 # xmm0 = xmm0[0,1],xmm1[2,3]
vmovaps %ymm0, (%rsi)
vzeroupper
retq

Now we generate this:

vmovsd  (%rdi), %xmm0           # xmm0 = mem[0],zero
vmovaps %ymm0, (%rsi)
vzeroupper
retq

As a side note: that VZEROUPPER is completely redundant...

I guess the vzeroupper insertion pass doesn't realize that the definition of
%xmm0 from vmovsd is already zeroing the upper half of %ymm0. Note that on
%-mcpu=btver2, we don't get that vzeroupper because pass vzeroupper insertion
%pass is disabled.

Differential Revision: https://reviews.llvm.org/D55274

llvm-svn: 348522
2018-12-06 19:55:38 +00:00
Sanjay Patel bfc7ffa40f [DAGCombiner] don't hoist logic op if operands have other uses, part 2
The PPC test with 2 extra uses seems clearly better by avoiding this transform. 
With 1 extra use, we also prevent an extra register move (although that might
be an RA problem). The general rule should be to only make a change here if
it is always profitable. The x86 diffs are all neutral.

llvm-svn: 348518
2018-12-06 19:18:56 +00:00
Simon Pilgrim 845d5a0aa8 Fix Wdocumentation warning. NFCI.
llvm-svn: 348517
2018-12-06 19:17:28 +00:00
Sanjay Patel c3717cd0d5 [DAGCombiner] don't hoist logic op if operands have other uses
The AVX512 diffs are neutral, but the bswap test shows a clear overreach in 
hoistLogicOpWithSameOpcodeHands(). If we don't check for other uses, we can 
increase the instruction count.

This could also fight with transforms trying to go in the opposite direction 
and possibly blow up/infinite loop. This might be enough to solve the bug 
noted here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181203/608593.html

I did not add the hasOneUse() checks to all opcodes because I see a perf 
regression for at least one opcode. We may decide that's irrelevant in the
face of potential compiler crashing, but I'll see if I can salvage that first.

llvm-svn: 348508
2018-12-06 18:16:32 +00:00