Commit Graph

1168 Commits

Author SHA1 Message Date
Sjoerd Meijer 520a18df9c Revert of r281304 as it is causing build bot failures in hexagon
hwloop regression tests. These tests pass locally; will be investigating
where these differences come from.

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

Patch by Sam Parker and Sjoerd Meijer.

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

llvm-svn: 281304
2016-09-13 08:08:06 +00:00
Sam Parker 62965c96df [ARM] Improve sxta{b|h} and uxta{b|h} tests
Created a Thumb2 predicated pattern matcher that uses Thumb2 and
HasT2ExtractPack and used it to redefine the patterns for sxta{b|h}
and uxta{b|h}. Also used the similar patterns to fill in isel pattern
gaps for the corresponding instructions in the ARM backend.
The patch is mainly changes to tests since most of this functionality
appears not to have been tested.

Differential Revision: https://reviews.llvm.org/D23273

llvm-svn: 278207
2016-08-10 09:34:34 +00:00
Sam Parker 18bc3a002e [ARM] Improve smul* and smla* isel for Thumb2
Added (sra (shl x, 16), 16) to the sext_16_node PatLeaf for ARM to
simplify some pattern matching. This has allowed several patterns
for smul* and smla* to be removed as well as making it easier to add
the matching for the corresponding instructions for Thumb2 targets.
Also added two Pat classes that are predicated on Thumb2 with the
hasDSP flag and UseMulOps flags. Updated the smul codegen test with
the wider range of patterns plus the ThumbV6 and ThumbV6T2 targets.

Differential Revision: https://reviews.llvm.org/D22908

llvm-svn: 277450
2016-08-02 12:44:27 +00:00
Bernard Ogden 849f737155 [ARM] Some saturation instructions not DSP-only
Summary:
Commit 276701 requires that targets have the DSP extensions to use
certain saturating instructions. This requires some corrections.

For ARM ISA the instructions in question are available in all v6*
architectures.

For Thumb2, the instructions in question are available from v6T2.
SSAT and USAT are part of the base architecture while SSAT16 and
USAT16 require the DSP extensions.

Reviewers: rengolin

Subscribers: aemerson, rengolin, samparker, llvm-commits

Differential Revision: https://reviews.llvm.org/D23010

llvm-svn: 277439
2016-08-02 10:04:03 +00:00
Renato Golin 32b165f561 [ARM] Saturation instructions are DSP-only
The saturation instructions appeared in v6T2, with DSP extensions, but they
were being accepted / generated on any, with the new introduction of the
saturation detection in the back-end. This commit restricts the usage to
DSP-enable only cores.

Fixes PR28607.

llvm-svn: 276701
2016-07-25 22:25:25 +00:00
Tim Northover 3e0361710a ARM: validate immediate branch targets in AsmParser.
Immediate branch targets aren't commonly used, but if they are we should make
sure they can actually be encoded. This means they must be divisible by 2 when
targeting Thumb mode, and by 4 when targeting ARM mode.

Also do a little naming cleanup while I was changing everything around anyway.

llvm-svn: 275116
2016-07-11 22:29:37 +00:00
Ahmed Bougacha 241e74cbc2 [ARM] Remove dead SDNodes. NFC.
The opcodes are used, but only by DAG->DAG.

llvm-svn: 273717
2016-06-24 20:38:00 +00:00
Pablo Barrio 7a64346533 [ARM] Lower (select_cc k k (select_cc ~k ~k x)) into (SSAT l_k x)
Summary:
SSAT saturates an integer, making sure that its value lies within
an interval [-k, k]. Since the constant is given to SSAT as the
number of bytes set to one, k + 1 must be a power of 2, otherwise
the optimization is not possible. Also, the select_cc must use <
and > respectively so that they define an interval.

Reviewers: mcrosier, jmolloy, rengolin

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D21372

llvm-svn: 273581
2016-06-23 16:53:49 +00:00
Diana Picus c5baa43f53 [ARM] Do not test for CPUs, use SubtargetFeatures (Part 1). NFCI
This is a cleanup commit similar to r271555, but for ARM.

The end goal is to get rid of the isSwift / isCortexXY / isWhatever methods.

Since the ARM backend seems to have quite a lot of calls to these methods, I
intend to submit 5-6 subtarget features at a time, instead of one big lump.

Differential Revision: http://reviews.llvm.org/D21432

llvm-svn: 273544
2016-06-23 07:47:35 +00:00
Sam Parker d616cf07b2 [ARM] Enable isel of UMAAL
TargetLowering and DAGToDAG are used to combine ADDC, ADDE and UMLAL
dags into UMAAL. Selection is split into the two phases because it
is easier to match the two patterns at those different times.

Differential Revision: http://http://reviews.llvm.org/D21461

llvm-svn: 273165
2016-06-20 16:47:09 +00:00
Ranjeet Singh 39d2d097d6 [ARM] Add support for mrrc/mrrc2 intrinsics.
Reapplying patch as it was reverted when it was first
committed because of an assertion failure when the
mrrc2 intrinsic was called in ARM mode. The failure
was happening because the instruction was being built
in ARMISelDAGToDAG.cpp and the tablegen description for
mrrc2 instruction doesn't allow you to use a predicate.

The ARM architecture manuals do say that mrrc2 in ARM
mode can be predicated with AL in assembly but this has
no effect on the encoding of the instruction as the top
4 bits will always be 1111 not 1110 which is the encoding
for the condition AL.

Differential Revision: http://reviews.llvm.org/D21408

llvm-svn: 272982
2016-06-17 00:52:41 +00:00
Ranjeet Singh 0db7be886e Reverting r272778 because there's an assertion
failure when running the test CodeGen/ARM/intrinsics-coprocessor.ll

llvm-svn: 272791
2016-06-15 14:23:29 +00:00
Ranjeet Singh 351364fe76 [ARM] Add support for mrrc/mrrc2 intrinsics.
Differential Revision: http://reviews.llvm.org/D21178

llvm-svn: 272778
2016-06-15 11:32:24 +00:00
Ranjeet Singh 933e1aa39f [ARM] Reverting r272544 because clang patch needs
to go in as soon as llvm patch has gone in because
tests will start breaking in Clang.

llvm-svn: 272546
2016-06-13 10:58:24 +00:00
Ranjeet Singh 8feacb330d [ARM] Add mrrc/mrrc2 co-processor intrinsics
MRRC/MRRC2 instruction writes to two registers. The
intrinsic definition returns a single uint64_t to
represent the write, this is a compact way of
representing a write to two 32 bit registers,
the alternative might have been two return a
struct of 2 uint32_t's but this isn't as nice.

Differential Revision: 

llvm-svn: 272544
2016-06-13 10:43:50 +00:00
Oliver Stannard b3378e2f3c [ARM] MSR instructions implicitly set CPSR
The MSR instructions can write to the CPSR, but we did not model this
fact, so we could emit them in the middle of IT blocks, changing the
condition flags for later instructions in the block.

The tests use two calls to llvm.write_register.i32 because it is valid
to use these instructions at the end of an IT block, which if conversion
does do in some cases. With two calls, the first clobbers the flags, so
a branch has to be used to make the second one conditional.

Differential Revision: http://reviews.llvm.org/D21139

llvm-svn: 272154
2016-06-08 15:26:34 +00:00
Sjoerd Meijer d906bf1369 RAS extensions are part of ARMv8.2-A. This change enables them by introducing a
new instruction to ARM and AArch64 targets and several system registers.

Patch by: Roger Ferrer Ibanez and Oliver Stannard

Differential Revision: http://reviews.llvm.org/D20282

llvm-svn: 271670
2016-06-03 14:03:27 +00:00
Sjoerd Meijer 9da258d8e5 ARM target does not use printAliasInstr machinery which
forces having special checks in ArmInstPrinter::printInstruction. This
patch addresses this issue.

Not all special checks could be removed: either they involve elaborated
conditions under which the alias is emitted (e.g. ldm/stm on sp may be
pop/push but only if the number of registers is >= 2) or the number
of registers is multivalued (like happens again with ldm/stm) and they
do not match the InstAlias pattern which assumes single-valued operands
in the pattern.

Patch by: Roger Ferrer Ibanez

Differential Revision: http://reviews.llvm.org/D20237

llvm-svn: 271667
2016-06-03 13:19:43 +00:00
Ranjeet Singh 16c24f4d6e [ARM] Add backend support for load/store intrinsics.
Added support to map intrinsics
__builtin_arm_{ldc,ldcl,ldc2,ldc2l,stc,stcl,stc2,stc2l}
to their ARM instructions.

Differential Revision: http://reviews.llvm.org/D20564

llvm-svn: 271271
2016-05-31 12:39:30 +00:00
Renato Golin 57bfb69aa4 [ARM] ARM mov InstAlias for MOVW lacks HasV6T2
The movw instruction is only available in ARM state for V6T2 and above.
The MOVi16 instruction has requirement HasV6T2 but the InstAlias
for mov rd, imm where the operand is imm0_65535_expr:$imm does not.

This means that movw can incorrectly be used in ARMv4 and ARMv5 by
writing mov rd, 0x1234. The simple fix is to the requirement HasV6T2
to the InstAlias. Tests added to not-armv4.s.

Patch by Peter Smith.

llvm-svn: 269761
2016-05-17 13:05:28 +00:00
Renato Golin 3f126138a1 [ARM] Delay ARM constant pool creation. NFC.
This change adds a new constant pool kind to ARMOperand. When parsing the
operand for =immediate we create an instance of this operand rather than
creating a constant pool entry and rewriting the operand.

As the new operand kind is only created for ldr rt,= we can make ldr rt,=
an explicit pseudo instruction in ARM, Thumb and Thumb2

The pseudo instruction is expanded in processInstruction(). This creates the
constant pool and transforms the pseudo instruction into a pc-relative ldr to
the constant pool.

There are no functional changes and no modifications needed to existing tests.

Required by the patch that fixes PR25722.

Patch by Peter Smith.

llvm-svn: 269352
2016-05-12 21:22:31 +00:00
Saleem Abdulrasool a028853540 ARM: restrict register class for WIN__DBZCHK
WIN__DBZCHK will insert a CBZ instruction into the stream.  This instruction
reserves 3 bits for the condition register (rn).  As such, we must ensure that
we restrict the register to a low register.  Use the tGPR class instead of GPR
to ensure that this is properly constrained.  In debug builds, we would attempt
to use lr as a condition register which would silently get truncated with no
hint that the register selection was incorrect.

llvm-svn: 267080
2016-04-21 23:53:19 +00:00
Tim Northover b629c77692 ARM: use a pseudo-instruction for cmpxchg at -O0.
The fast register-allocator cannot cope with inter-block dependencies without
spilling. This is fine for ldrex/strex loops coming from atomicrmw instructions
where any value produced within a block is dead by the end, but not for
cmpxchg. So we lower a cmpxchg at -O0 via a pseudo-inst that gets expanded
after regalloc.

Fortunately this is at -O0 so we don't have to care about performance. This
simplifies the various axes of expansion considerably: we assume a strong
seq_cst operation and ensure ordering via the always-present DMB instructions
rather than v8 acquire/release instructions.

Should fix the 32-bit part of PR25526.

llvm-svn: 266679
2016-04-18 21:48:55 +00:00
JF Bastien 800f87a871 NFC: make AtomicOrdering an enum class
Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.

The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).

This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.

As a follow-up I'll add:
  bool operator<(AtomicOrdering, AtomicOrdering) = delete;
  bool operator>(AtomicOrdering, AtomicOrdering) = delete;
  bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
  bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.

Reviewers: jyknight, reames

Subscribers: jyknight, llvm-commits

Differential Revision: http://reviews.llvm.org/D18775

llvm-svn: 265602
2016-04-06 21:19:33 +00:00
Sam Parker 0d3a3a537c [ARM] Cleanup of smul and smla instruction descriptions
Removed the SDNode argument passed to the AI_smul and AI_smla multiclass
definitions as they are always mul.

Differential Revision: http://reviews.llvm.org/D18791

llvm-svn: 265409
2016-04-05 16:01:25 +00:00
Saleem Abdulrasool 1632fe1f77 ARM: follow up improvements for SVN r263118
The initial change was insufficiently complete for always getting the semantics
of __builtin_longjmp correct.  The builtin is translated into a
`tInt_eh_sjlj_longjmp` DAG node.  This node set R7 as clobbered.  However, the
code would then follow up with a clobber of R11.  I had failed to notice the
imp-def,kill on R7 in the isel.  Unfortunately, it seems that it is not possible
to conditionalise the Defs list via an !if.  Instead, construct a new parallel
WIN node and prefer that when targeting windows.  This ensures that we now both
correctly model the __builtin_longjmp as well as construct the frame in a more
ABI conformant manner.

llvm-svn: 263123
2016-03-10 16:26:37 +00:00
Artyom Skrobov 5ddea6a8e9 [ARM] Simplify ARMInstr*.td by getting rid of identity PatFrags (NFC)
Reviewers: t.p.northover, grosbach, resistor

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D17636

llvm-svn: 262936
2016-03-08 16:23:54 +00:00
Saleem Abdulrasool f36005a358 ARM: support TLS for WoA
Add support for TLS access for Windows on ARM.  This generates a similar access
to MSVC for ARM.

The changes to the tablegen data is needed to support loading an external symbol
global that is not for a call.  The adjustments to the DAG to DAG transforms are
needed to preserve the 32-bit move.

llvm-svn: 259676
2016-02-03 18:21:59 +00:00
Bradley Smith fed3e4ac00 [ARM] Add ARMv8-M security extension instructions to ARMv8-M Baseline/Mainline
This patch was originally committed as r257883, but was reverted due to windows
failures. The cause of these failures has been fixed under r258677, hence
re-committing the original patch.

llvm-svn: 258681
2016-01-25 11:24:47 +00:00
Oliver Stannard 65b85382f6 [ARM] Add ARMv8.2-A FP16 scalar instructions
This was originally committed as r255762, but reverted as it broke windows
bots. Re-commitiing the exact same patch, as the underlying cause was fixed by
r258677.

ARMv8.2-A adds 16-bit floating point versions of all existing VFP
floating-point instructions. This is an optional extension, so all of
these instructions require the FeatureFullFP16 subtarget feature.

The assembly for these instructions uses S registers (AArch32 does not
have H registers), but the instructions have ".f16" type specifiers
rather than ".f32" or ".f64". The top 16 bits of each source register
are ignored, and the top 16 bits of the destination register are set to
zero.

These instructions are mostly the same as the 32- and 64-bit versions,
but they use coprocessor 9 rather than 10 and 11.

Two new instructions, VMOVX and VINS, have been added to allow packing
and extracting two 16-bit floats stored in the top and bottom halves of
an S register.

New fixup kinds have been added for the PC-relative load and store
instructions, but no ELF relocations have been added as they have a
range of 512 bytes.

Differential Revision: http://reviews.llvm.org/D15038

llvm-svn: 258678
2016-01-25 10:26:26 +00:00
Oliver Stannard 9f68749eba [ARM] Operands for PKHTB alias should be swapped
When the shift immediate is zero, PKHTB is an alias for PKHBT, but the order of
the input operands needs to be swapped.

Differential Revision: http://reviews.llvm.org/D16288

llvm-svn: 258044
2016-01-18 11:56:35 +00:00
Reid Kleckner d4a0d18899 Revert "[ARM] Add ARMv8-M security extension instructions to ARMv8-M Baseline/Mainline"
This reverts commit r257883.

Somehow this didn't make it into r257916.

llvm-svn: 257919
2016-01-15 18:55:12 +00:00
Bradley Smith 618712df04 [ARM] Add ARMv8-M security extension instructions to ARMv8-M Baseline/Mainline
llvm-svn: 257883
2016-01-15 10:27:14 +00:00
Bradley Smith e26f799422 [ARM] Add ARMv8-M Baseline/Mainline LLVM targeting
llvm-svn: 257878
2016-01-15 10:24:39 +00:00
Bradley Smith 4c21cba72b [ARM] Split out ARMv8-A semaphores and atomics and ARMv7 clrex as separate features
llvm-svn: 257877
2016-01-15 10:23:46 +00:00
Tim Northover bd41cf880c ARM: support TLS accesses on Darwin platforms
Darwin TLS accesses most closely resemble ELF's general-dynamic situation,
since they have to be able to handle all possible situations. The descriptors
and so on are obviously slightly different though.

llvm-svn: 257039
2016-01-07 09:03:03 +00:00
Roman Divacky 73fc84761f Support clrex instruction on ARMv6k. Patch by Andrew Turner.
llvm-svn: 256505
2015-12-28 17:47:23 +00:00
Reid Kleckner 187d33ee74 Revert "[ARM] Add ARMv8.2-A FP16 scalar instructions"
This reverts commit r255762.

llvm-svn: 255806
2015-12-16 19:21:03 +00:00
Oliver Stannard 48568cbe18 [ARM] Add ARMv8.2-A FP16 scalar instructions
ARMv8.2-A adds 16-bit floating point versions of all existing VFP
floating-point instructions. This is an optional extension, so all of
these instructions require the FeatureFullFP16 subtarget feature.

The assembly for these instructions uses S registers (AArch32 does not
have H registers), but the instructions have ".f16" type specifiers
rather than ".f32" or ".f64". The top 16 bits of each source register
are ignored, and the top 16 bits of the destination register are set to
zero.

These instructions are mostly the same as the 32- and 64-bit versions,
but they use coprocessor 9 rather than 10 and 11.

Two new instructions, VMOVX and VINS, have been added to allow packing
and extracting two 16-bit floats stored in the top and bottom halves of
an S register.

New fixup kinds have been added for the PC-relative load and store
instructions, but no ELF relocations have been added as they have a
range of 512 bytes.

Differential Revision: http://reviews.llvm.org/D15038

llvm-svn: 255762
2015-12-16 11:35:44 +00:00
Renato Golin 412ee3d45d [ARM] Allowing SP/PC for AND/BIC mod_imm_not
AND/BIC instructions do accept SP/PC, so the register class should be
more generic (rGPR -> GPR) to cope with that case. Adding more tests.

llvm-svn: 255034
2015-12-08 18:10:58 +00:00
Oliver Stannard 8addbf4350 [ARM] Add subtarget features for ARMv8.2-A
This adds subtarget features for ARMv8.2-A, which builds on (and
requires the features from) ARMv8.1-A. Most assembler-visible features
of ARMv8.2-A are system instructions, and are all required parts of the
architecture, so just depend on the HasV8_2aOps subtarget feature.
There is also one large, optional feature, which adds 16-bit floating
point versions of all existing floating-point instructions (VFP and
SIMD), this is represented by the FeatureFullFP16 subtarget feature.

Differential Revision: http://reviews.llvm.org/D15036

llvm-svn: 254399
2015-12-01 10:23:06 +00:00
James Molloy b564098c62 [ARM] Replace ARMISD::RBIT with ISD::BITREVERSE
ISD::BITREVERSE matches "rbit" completely, so remove ARMISD::RBIT and mark ISD::BITREVERSE as legal, adding a test for lowering.

llvm-svn: 253047
2015-11-13 16:05:22 +00:00
Artyom Skrobov 0ff1ce4038 Recognize that ARM1176JZ[F]-S support TrustZone
Summary:
ARMv6KZ cores were set up incorrectly in ARM.td; also, the SMI mnemonic
(the old name for SMC, as defined in ARMv6KZ) wasn't supported.

Reviewers: jmolloy, rengolin

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D14154

llvm-svn: 251627
2015-10-29 13:56:19 +00:00
Asiri Rathnayake 1040a53be3 Fix mapping of @llvm.arm.ssat/usat intrinsics to ssat/usat instructions
The mapping of these two intrinsics in ARMInstrInfo.td had a small
omission which lead to their operands not being validated/transformed
before being lowered into usat and ssat instructions. This can cause
incorrect instructions to be emitted.

I've also added tests for the remaining two saturating arithmatic
intrinsics @llvm.arm.qadd and @llvm.arm.qsub as they are missing
codegen tests.

llvm-svn: 250697
2015-10-19 11:44:24 +00:00
Scott Douglass 953f908173 [ARM] Modify codegen for memcpy intrinsic to prefer LDM/STM.
We were previously codegen'ing memcpy as regular load/store operations and
hoping that the register allocator would allocate registers in ascending order
so that we could apply an LDM/STM combine after register allocation. According
to the commit that first introduced this code (r37179), we planned to teach the
register allocator to allocate the registers in ascending order. This never got
implemented, and up to now we've been stuck with very poor codegen.

A much simpler approach for achieving better codegen is to create MEMCPY pseudo
instructions, attach scratch virtual registers to them and then, post register
allocation, expand the MEMCPYs into LDM/STM pairs using the scratch registers.
The register allocator will have picked arbitrary registers which we sort when
expanding the MEMCPY. This approach also avoids the need to repeatedly calculate
offsets which ultimately ought to be eliminated pre-RA in order to decrease
register pressure.

Fixes PR9199 and PR23768.

[This is based on Peter Collingbourne's r238473 which was reverted.]

Differential Revision: http://reviews.llvm.org/D13239

Change-Id: I727543c2e94136e0f80b8e22d5642d7b9ee5b458
Author: Peter Collingbourne <peter@pcc.me.uk>
llvm-svn: 249322
2015-10-05 14:49:54 +00:00
Saleem Abdulrasool fe83b50289 ARM: address WoA division limitation
We now emit the compiler generated divide by zero check that was needed for the
MSVC routines.  We construct a psuedo-instruction for the DBZ check as the
operation requires splitting up the BB.  For the 64-bit operations, we need to
custom expand the node as we need to insert the DBZ check and then emit the
libcall to the appropriate name.  Because this is target specific, it seemed
better to reproduce the expansion operation from the target-agnostic type
legalization rather than sink this there to avoid the duplication.  The division
library calls now match MSVC semantically.

llvm-svn: 248561
2015-09-25 05:15:46 +00:00
Artyom Skrobov cf296444ab [ARM] Handle +t2dsp feature as an ArchExtKind in ARMTargetParser.def
Currently, the availability of DSP instructions (ACLE 6.4.7) is handled in a
hand-rolled tricky condition block in tools/clang/lib/Basic/Targets.cpp, with
a FIXME: attached.

This patch changes the handling of +t2dsp to be in line with other
architecture extensions.

Following a revert of r248152 and new review comments, this patch also includes
renaming FeatureDSPThumb2 -> FeatureDSP, hasThumb2DSP() -> hasDSP(), etc.
The spelling of "t2dsp" is preserved, pending a further investigation of its
possible external usage.

Differential Revision: http://reviews.llvm.org/D12937

llvm-svn: 248519
2015-09-24 17:31:16 +00:00
James Molloy ea3a687a33 [ARM] Replace ARMISD::VMINNM/VMAXNM with ISD::FMINNUM/FMAXNUM
NFCI. This replaces another custom ISDNode with a generic equivalent.

llvm-svn: 244591
2015-08-11 12:06:22 +00:00
Matthias Braun 3cd00c1739 Fix __builtin_setjmp in combination with sjlj exception handling.
llvm.eh.sjlj.setjmp was used as part of the SjLj exception handling
style but is also used in clang to implement __builtin_setjmp.  The ARM
backend needs to output additional dispatch tables for the SjLj
exception handling style, these tables however can't be emitted if
llvm.eh.sjlj.setjmp is simply used for __builtin_setjmp and no actual
landing pad blocks exist.

To solve this issue a new llvm.eh.sjlj.setup_dispatch intrinsic is
introduced which is used instead of llvm.eh.sjlj.setjmp in the SjLj
exception handling lowering, so we can differentiate between the case
where we actually need to setup a dispatch table and the case where we
just need the __builtin_setjmp semantic.

Differential Revision: http://reviews.llvm.org/D9313

llvm-svn: 242481
2015-07-16 22:34:16 +00:00