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Commit Graph

35228 Commits

Author SHA1 Message Date
Lang Hames
3078627938 Revert "Re-revert r343129."
This reverts commit 4e2557dbc76704beb8c4cf1191cb786e719db5d3.

llvm-svn: 343161
2018-09-27 02:09:36 +00:00
Lang Hames
0772f8e0fa Re-revert r343129.
Apparently the fixes in r343149 did not cover all the issues. Re-reverting
while I investigate.

llvm-svn: 343151
2018-09-26 23:32:53 +00:00
Lang Hames
b54504056f Reapply r343129 with fix.
Explicitly defines ThreadSafeModule's move-assignment operator to move fields in
reverse order. This is required to ensure that the context field outlives the
module field.

llvm-svn: 343149
2018-09-26 22:34:33 +00:00
Lang Hames
dc69059bb0 Revert r343129 "[ORC] Change the field order of ThreadSafeModule to ensure the "
It broke several bots.

llvm-svn: 343133
2018-09-26 19:36:30 +00:00
Lang Hames
b3444fe032 [ORC] Change the field order of ThreadSafeModule to ensure the Module is
destroyed before its ThreadSharedContext.

Destroying the context first is an error if this ThreadSafeModule is the only
owner of its underlying context.

Add a unit test for ThreadSafeModule/ThreadSafeContext to catch this and other
basic usage issues.

llvm-svn: 343129
2018-09-26 18:50:01 +00:00
Lang Hames
17fb5edbbb Reapply r343058 with a fix for -DLLVM_ENABLE_THREADS=OFF.
Modifies lit to add a 'thread_support' feature that can be used in lit test
REQUIRES clauses. The thread_support flag is set if -DLLVM_ENABLE_THREADS=ON
and unset if -DLLVM_ENABLE_THREADS=OFF. The lit flag is used to disable the
multiple-compile-threads-basic.ll testcase when threading is disabled.

llvm-svn: 343122
2018-09-26 16:26:59 +00:00
Luke Cheeseman
aa2bb63fda Revert r343112 as CallFrameString API change has broken lldb builds
llvm-svn: 343114
2018-09-26 14:48:03 +00:00
Luke Cheeseman
adcedeea67 [AArch64] - Return address signing dwarf support
- Reapply r343089 with a fix for DebugInfo/Sparc/gnu-window-save.ll

llvm-svn: 343112
2018-09-26 14:30:29 +00:00
Fedor Sergeev
5959c7e9c5 [PassTiming] cleaning up legacy PassTimingInfo interface. NFCI.
During D51276 discussion it was decided that legacy PassTimingInfo
interface can not be reused for new pass manager's implementation
of -time-passes.

This is a cleanup in preparation for D51276 to make legacy interface
as concise as possible, moving the PassTimingInfo from the header
into the anonymous legacy namespace in .cpp.

It is rather close to a revert of rL340872 in a sense that it hides
the interface and gets rid of templates. However as compared to
a complete revert it resides in a different translation unit and has
an additional pass-instance counting funcitonality (PassIDCountMap).

Reviewers: philip.pfaffe
Differential Revision: https://reviews.llvm.org/D52356

llvm-svn: 343104
2018-09-26 13:01:43 +00:00
Hans Wennborg
905bc345c4 Revert r343089 "[AArch64] - Return address signing dwarf support"
This caused the DebugInfo/Sparc/gnu-window-save.ll test to fail.

> Functions that have signed return addresses need additional dwarf support:
> - After signing the LR, and before authenticating it, the LR register is in a
>   state the is unusable by a debugger or unwinder
> - To account for this a new directive, .cfi_negate_ra_state, is added
> - This directive says the signed state of the LR register has now changed,
>   i.e. unsigned -> signed or signed -> unsigned
> - This directive has the same CFA code as the SPARC directive GNU_window_save
>   (0x2d), adding a macro to account for multiply defined codes
> - This patch matches the gcc implementation of this support:
>   https://patchwork.ozlabs.org/patch/800271/
>
> Differential Revision: https://reviews.llvm.org/D50136

llvm-svn: 343103
2018-09-26 12:57:45 +00:00
Oliver Stannard
347bc189fb [ARM/AArch64][v8.5A] Add Armv8.5-A target
This patch allows targeting Armv8.5-A, adding the architecture to
tablegen and setting the options to be identical to Armv8.4-A for the
time being. Subsequent patches will add support for the different
features included in the Armv8.5-A Reference Manual.

Patch by Pablo Barrio!

Differential revision: https://reviews.llvm.org/D52470

llvm-svn: 343102
2018-09-26 12:48:21 +00:00
Hans Wennborg
a89f546d6a Revert r343058 "[ORC] Add support for multithreaded compiles to LLJIT and LLLazyJIT."
This doesn't work well in builds configured with LLVM_ENABLE_THREADS=OFF,
causing the following assert when running
ExecutionEngine/OrcLazy/multiple-compile-threads-basic.ll:

  lib/ExecutionEngine/Orc/Core.cpp:1748: Expected<llvm::JITEvaluatedSymbol>
  llvm::orc::lookup(const llvm::orc::JITDylibList &, llvm::orc::SymbolStringPtr):
  Assertion `ResultMap->size() == 1 && "Unexpected number of results"' failed.

> LLJIT and LLLazyJIT can now be constructed with an optional NumCompileThreads
> arguments. If this is non-zero then a thread-pool will be created with the
> given number of threads, and compile tasks will be dispatched to the thread
> pool.
>
> To enable testing of this feature, two new flags are added to lli:
>
> (1) -compile-threads=N (N = 0 by default) controls the number of compile threads
> to use.
>
> (2) -thread-entry can be used to execute code on additional threads. For each
> -thread-entry argument supplied (multiple are allowed) a new thread will be
> created and the given symbol called. These additional thread entry points are
> called after static constructors are run, but before main.

llvm-svn: 343099
2018-09-26 12:15:23 +00:00
Clement Courbet
6514f1c243 [llvm-exegesis] Add support for measuring NumMicroOps.
Summary:
Example output for vzeroall:

---
mode:            uops
key:
  instructions:
    - 'VZEROALL'
  config:          ''
  register_initial_values:
cpu_name:        haswell
llvm_triple:     x86_64-unknown-linux-gnu
num_repetitions: 10000
measurements:
  - { debug_string: HWPort0, value: 0.0006, per_snippet_value: 0.0006,
      key: '3' }
  - { debug_string: HWPort1, value: 0.0011, per_snippet_value: 0.0011,
      key: '4' }
  - { debug_string: HWPort2, value: 0.0004, per_snippet_value: 0.0004,
      key: '5' }
  - { debug_string: HWPort3, value: 0.0018, per_snippet_value: 0.0018,
      key: '6' }
  - { debug_string: HWPort4, value: 0.0002, per_snippet_value: 0.0002,
      key: '7' }
  - { debug_string: HWPort5, value: 1.0019, per_snippet_value: 1.0019,
      key: '8' }
  - { debug_string: HWPort6, value: 1.0033, per_snippet_value: 1.0033,
      key: '9' }
  - { debug_string: HWPort7, value: 0.0001, per_snippet_value: 0.0001,
      key: '10' }
  - { debug_string: NumMicroOps, value: 20.0069, per_snippet_value: 20.0069,
      key: NumMicroOps }
error:           ''
info:            ''
assembled_snippet: C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C5FC77C3
...

Reviewers: gchatelet

Subscribers: tschuett, RKSimon, andreadb, llvm-commits

Differential Revision: https://reviews.llvm.org/D52539

llvm-svn: 343094
2018-09-26 11:22:56 +00:00
Luke Cheeseman
05f11dbf44 [AArch64] - Return address signing dwarf support
Functions that have signed return addresses need additional dwarf support:
- After signing the LR, and before authenticating it, the LR register is in a
  state the is unusable by a debugger or unwinder
- To account for this a new directive, .cfi_negate_ra_state, is added
- This directive says the signed state of the LR register has now changed,
  i.e. unsigned -> signed or signed -> unsigned
- This directive has the same CFA code as the SPARC directive GNU_window_save
  (0x2d), adding a macro to account for multiply defined codes
- This patch matches the gcc implementation of this support:
  https://patchwork.ozlabs.org/patch/800271/

Differential Revision: https://reviews.llvm.org/D50136

llvm-svn: 343089
2018-09-26 10:14:15 +00:00
Mikael Nilsson
51909daeee Run VerifyDAGDiverence in debug only
VerifyDAGDiverence costs compilation time, avoid running it in non-debug
builds.

Differential Revision: https://reviews.llvm.org/D52454

llvm-svn: 343086
2018-09-26 09:25:45 +00:00
Martin Storsjo
6df91f458f [ORC] Remove a superfluous semicolon, fixing warnings. NFC.
llvm-svn: 343068
2018-09-26 06:13:03 +00:00
Lang Hames
5eec37df52 [ORC] Update CompileOnDemandLayer2 to use the new lazyReexports mechanism
for lazy compilation, rather than a callback manager.

The new mechanism does not block compile threads, and does not require
function bodies to be renamed.

Future modifications should allow laziness on a per-module basis to work
without any modification of the input module.

llvm-svn: 343065
2018-09-26 05:08:29 +00:00
Lang Hames
310a62559f [ORC] Add a "lazy call-through" utility based on the same underlying trampoline
implementation as lazy compile callbacks, and a "lazy re-exports" utility that
builds lazy call-throughs.

Lazy call-throughs are similar to lazy compile callbacks (and are based on the
same underlying state saving/restoring trampolines) but resolve their targets
by performing a standard ORC lookup rather than invoking a user supplied
compiler callback. This allows them to inherit the thread-safety of ORC lookups
while blocking only the calling thread (whereas compile callbacks also block one
compile thread).

Lazy re-exports provide a simple way of building lazy call-throughs. Unlike a
regular re-export, a lazy re-export generates a new address (a stub entry point)
that will act like the re-exported symbol when called. The first call via a
lazy re-export will trigger compilation of the re-exported symbol before calling
through to it.

llvm-svn: 343061
2018-09-26 04:18:30 +00:00
Lang Hames
fceb425485 [ORC] Refactor trampoline pool management out of JITCompileCallbackManager.
This will allow trampoline pools to be re-used for a new lazy-reexport utility
that generates looks up function bodies using the standard symbol lookup process
(rather than using a user provided compile function). This new utility provides
the same capabilities (since MaterializationUnits already allow user supplied
compile functions to be run) as JITCompileCallbackManager, but can use the new
asynchronous lookup functions to avoid blocking a compile thread.

This patch also updates createLocalCompileCallbackManager to return an error if
a callback manager can not be created, and updates clients of that API to
account for the change. Finally, the OrcCBindingsStack is updates so that if
a callback manager is not available for the target platform a valid stack
(without support for lazy compilation) can still be constructed.

llvm-svn: 343059
2018-09-26 03:32:12 +00:00
Lang Hames
49b25f7a75 [ORC] Add support for multithreaded compiles to LLJIT and LLLazyJIT.
LLJIT and LLLazyJIT can now be constructed with an optional NumCompileThreads
arguments. If this is non-zero then a thread-pool will be created with the
given number of threads, and compile tasks will be dispatched to the thread
pool.

To enable testing of this feature, two new flags are added to lli:

(1) -compile-threads=N (N = 0 by default) controls the number of compile threads
to use.

(2) -thread-entry can be used to execute code on additional threads. For each
-thread-entry argument supplied (multiple are allowed) a new thread will be
created and the given symbol called. These additional thread entry points are
called after static constructors are run, but before main.

llvm-svn: 343058
2018-09-26 02:39:42 +00:00
Lang Hames
de6b20d3dc [ORC] Include-what-you-use fixes.
llvm-svn: 343057
2018-09-26 02:01:39 +00:00
Lang Hames
80e388bda7 [ORC] Fix a missing include in r343055.
llvm-svn: 343056
2018-09-26 01:54:13 +00:00
Lang Hames
7d9758f33a [ORC] Add ThreadSafeModule and ThreadSafeContext wrappers to support concurrent
compilation of IR in the JIT.

ThreadSafeContext is a pair of an LLVMContext and a mutex that can be used to
lock that context when it needs to be accessed from multiple threads.

ThreadSafeModule is a pair of a unique_ptr<Module> and a
shared_ptr<ThreadSafeContext>. This allows the lifetime of a ThreadSafeContext
to be managed automatically in terms of the ThreadSafeModules that refer to it:
Once all modules using a ThreadSafeContext are destructed, and providing the
client has not held on to a copy of shared context pointer, the context will be
automatically destructed.

This scheme is necessary due to the following constraits: (1) We need multiple
contexts for multithreaded compilation (at least one per compile thread plus
one to store any IR not currently being compiled, though one context per module
is simpler). (2) We need to free contexts that are no longer being used so that
the JIT does not leak memory over time. (3) Module lifetimes are not
predictable (modules are compiled as needed depending on the flow of JIT'd
code) so there is no single point where contexts could be reclaimed.

JIT clients not using concurrency can safely use one ThreadSafeContext for all
ThreadSafeModules.

JIT clients who want to be able to compile concurrently should use a different
ThreadSafeContext for each module, or call setCloneToNewContextOnEmit on their
top-level IRLayer. The former reduces compile latency (since no clone step is
needed) at the cost of additional memory overhead for uncompiled modules (as
every uncompiled module will duplicate the LLVM types, constants and metadata
that have been shared).

llvm-svn: 343055
2018-09-26 01:24:12 +00:00
Lang Hames
be5c285309 [ORC] Add an asynchronous jit-link function, jitLinkForORC, to RuntimeDyld and
switch RTDyldObjectLinkingLayer2 to use it.

RuntimeDyld::loadObject is currently a blocking operation. This means that any
JIT'd code whose call-graph contains an embedded complete K graph will require
at least K threads to link, which precludes the use of a fixed sized thread
pool for concurrent JITing of arbitrary code (whatever K the thread-pool is set
at, any code with a K+1 complete subgraph will deadlock at JIT-link time).

To address this issue, this commmit introduces a function called jitLinkForORC
that uses continuation-passing style to pass the fix-up and finalization steps
to the asynchronous symbol resolver interface so that linking can be performed
without blocking.

llvm-svn: 343043
2018-09-25 22:57:44 +00:00
Anna Thomas
146a9e87c5 [LV][LAA] Vectorize loop invariant values stored into loop invariant address
Summary:
We are overly conservative in loop vectorizer with respect to stores to loop
invariant addresses.
More details in https://bugs.llvm.org/show_bug.cgi?id=38546
This is the first part of the fix where we start with vectorizing loop invariant
values to loop invariant addresses.

This also includes changes to ORE for stores to invariant address.

Reviewers: anemet, Ayal, mkuper, mssimpso

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D50665

llvm-svn: 343028
2018-09-25 20:57:20 +00:00
Craig Topper
ff15ca143c [MCAsmParser] Move AltMacroMode tracking out of MCAsmLexer
The Lexer doesn't use this state itself. It is only set and used by AsmParser so it seems like it should just be part of AsmParser.

Differential Revision: https://reviews.llvm.org/D52515

llvm-svn: 343027
2018-09-25 20:55:55 +00:00
Lang Hames
bd45c5f4db Remove 'orc' namespace from MSVCErrorWorkarounds.h, fix some typos that were
breaking windows builds.

The 'orc' namespace was accidentally left in when the workarounds were moved
out of orc in r343011.

llvm-svn: 343025
2018-09-25 20:48:57 +00:00
Lang Hames
5324e0c217 Fix a missing includes and a use of the MSVC promise/future workaround that
were left out of r343011/r343012.

llvm-svn: 343022
2018-09-25 20:16:06 +00:00
Teresa Johnson
44ebb78e5e [ThinLTO] Efficiency fix for writing type id records in per-module indexes
Summary:
In D49565/r337503, the type id record writing was fixed so that only
referenced type ids were emitted into each per-module index for ThinLTO
distributed builds. However, this still left an efficiency issue: each
per-module index checked all type ids for membership in the referenced
set, yielding O(M*N) performance (M indexes and N type ids).

Change the TypeIdMap in the summary to be indexed by GUID, to facilitate
correlating with type identifier GUIDs referenced in the function
summary TypeIdInfo structures. This allowed simplifying other
places where a map from type id GUID to type id map entry was previously
being used to aid this correlation.

Also fix AsmWriter code to handle the rare case of type id GUID
collision.

For a large internal application, this reduced the thin link time by
almost 15%.

Reviewers: pcc, vitalybuka

Subscribers: mehdi_amini, inglorion, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D51330

llvm-svn: 343021
2018-09-25 20:14:40 +00:00
Heejin Ahn
ab02666df3 Unify landing pad information adding routines (NFC)
Summary:
We have `llvm::addLandingPadInfo` and `MachineFunction::addLandingPad`,
both of which add landing pad information to populate `LandingPadInfo`
but are called from different locations, which was confusing. This patch
unifies them with one `MachineFunction::addLandingPad` function, which
now has functionlities of both functions.

Reviewers: rnk

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D52428

llvm-svn: 343018
2018-09-25 19:56:44 +00:00
Lang Hames
276d90bd36 [ORC] Reapply r342939 with a fix for MSVC's promise/future restrictions.
llvm-svn: 343012
2018-09-25 19:48:46 +00:00
Lang Hames
d1f4173f73 Move MSVC workarounds for future<Error>/future<Expected<T>> out of ORC and into
a header in support.

MSVC's std::future implementation requires types to be default constructible,
but Error and Expected are not. This issue came up once before in ORC's
RPCUtils.h header and was worked around there but came up again in r342939, so
I am moving the workaround to Support to make it available to other clients.

llvm-svn: 343011
2018-09-25 19:48:44 +00:00
Hans Wennborg
22f1fa8070 Revert r342637 "[ADT] Try again to use the same version of llvm::Optional on all compilers"
and also revert follow-ups r342643 and r342723.

This caused Clang to be miscompiled by GCC 4.8.4 (Unbuntu 14.04's
default compiler) and break the Chromium build (see
https://crbug.com/888061).

llvm-svn: 342966
2018-09-25 12:08:56 +00:00
Fangrui Song
cd25254f64 Add macro LLVM_ATTRIBUTE_REINITIALIZES
Summary:
This marks legitimate use-after-move (e.g. `Found.clear()` in rC342925)
which would otherwise be caught by bugprone-use-after-move.

bugprone-use-after-move recognizes this attribute after rCTE339571.

Reviewers: aaron.ballman, rsmith, mboehme, hokein

Reviewed By: mboehme

Subscribers: kristina, llvm-commits

Differential Revision: https://reviews.llvm.org/D52451

llvm-svn: 342949
2018-09-25 08:06:32 +00:00
Fangrui Song
556d8103ca Use unique_ptr to hold AsmInfo,MRI,MII,STI
Reviewers: pcc, dblaikie

Reviewed By: dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D52389

llvm-svn: 342945
2018-09-25 06:19:31 +00:00
Lang Hames
67265a68fd Revert "[ORC] Switch to asynchronous resolution in JITSymbolResolver."
This reverts commit r342939.

MSVC's promise/future implementation does not like types that are not default
constructible. Reverting while I figure out a solution.

llvm-svn: 342941
2018-09-25 04:54:03 +00:00
Lang Hames
c1dc6f5684 [ORC] Switch to asynchronous resolution in JITSymbolResolver.
Asynchronous resolution (where the caller receives a callback once the requested
set of symbols are resolved) is a core part of the new concurrent ORC APIs. This
change extends the asynchronous resolution model down to RuntimeDyld, which is
necessary to prevent deadlocks when compiling/linking on a fixed number of
threads: If RuntimeDyld's linking process were a blocking operation, then any
complete K-graph in a program will require at least K threads to link in the
worst case, as each thread would block waiting for all the others to complete.
Using callbacks instead allows the work to be passed between dependent threads
until it is complete.

For backwards compatibility, all existing RuntimeDyld functions will continue
to operate in blocking mode as before. This change will enable the introduction
of a new async finalization process in a subsequent patch to enable asynchronous
JIT linking.

llvm-svn: 342939
2018-09-25 04:43:38 +00:00
Stefan Pintilie
c79c70a413 [Power9] [LLVM] Add __float128 exponent GET and SET builtins
Added

__builtin_vsx_scalar_extract_expq
__builtin_vsx_scalar_insert_exp_qp

Builtins should behave the same way as in GCC.

Differential Revision: https://reviews.llvm.org/D48185

llvm-svn: 342910
2018-09-24 18:14:13 +00:00
Fedor Sergeev
912a050cc8 [New PM][PassInstrumentation] IR printing support for New Pass Manager
Implementing -print-before-all/-print-after-all/-filter-print-func support
through PassInstrumentation callbacks.

- PrintIR routines implement printing callbacks.

- StandardInstrumentations class provides a central place to manage all
  the "standard" in-tree pass instrumentations. Currently it registers
  PrintIR callbacks.

Reviewers: chandlerc, paquette, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D50923

llvm-svn: 342896
2018-09-24 16:08:15 +00:00
Lang Hames
6ea4879787 [ORC] Add some debugging output to Core.h/Core.cpp
Core now logs when materialization units are dispatched or return to JITDylibs.

llvm-svn: 342853
2018-09-23 21:30:05 +00:00
Lang Hames
7815dbf10d [ORC] Update ORC C bindings to use the new llvm::Error C API.
This replaces instances of the LLVMOrcErrorCode type with LLVMErrorRef,
simplifying the implementation of the OrcCBindingsStack class and ORC
C API bindings and making it possible to return arbitrary (wrapped)
llvm::Errors.

llvm-svn: 342828
2018-09-23 02:09:18 +00:00
Zachary Turner
e9455fa60f Try moving this function to another file.
I can't reproduce this compilation failure so I can't really
test this fix.

llvm-svn: 342784
2018-09-21 23:00:37 +00:00
Lang Hames
f2c678b710 [ORC] In RTDyldObjectLinkingLayer, only call NotifyFreed if the object file
has been finalized.

This prevents crashes on unfinalized objects for clients using
JITEventListeners.

Patch by Geoff Levner. Thanks Geoff!

llvm-svn: 342783
2018-09-21 22:59:48 +00:00
Zachary Turner
22304a4398 [NativePDB] Add support for reading function signatures.
This adds support for parsing function signature records and returning
them through the native DIA interface.

llvm-svn: 342780
2018-09-21 22:36:28 +00:00
Zachary Turner
c07938cd80 [PDB] Add native reading support for UDT / class types.
This allows the native reader to find records of class/struct/
union type and dump them.  This behavior is tested by using the
diadump subcommand against golden output produced by actual DIA
SDK on the same PDB file, and again using pretty -native to
confirm that we actually dump the classes.  We don't find class
members or anything like that yet, for now it's just the class
itself.

llvm-svn: 342779
2018-09-21 22:36:04 +00:00
Fedor Sergeev
d3259add24 [New PM][PassInstrumentation] Adding PassInstrumentation to the AnalysisManager runs
As a prerequisite to time-passes implementation which needs to time both passes
and analyses, adding instrumentation points to the Analysis Manager.
The are two functional differences between Pass and Analysis instrumentation:
  - the latter does not increment pass execution counter
  - it does not provide ability to skip execution of the corresponding analysis

Reviewers: chandlerc, philip.pfaffe
Differential Revision: https://reviews.llvm.org/D51275

llvm-svn: 342778
2018-09-21 22:10:17 +00:00
Caroline Tice
c0b1b6c031 Pass code-model through Module IR to LTO which will use it.
Currently the code-model does not get saved in the module IR,
so if a code model is specified when compiling with LTO,
it gets lost and is not propagated properly to LTO. This patch,
along with one for the front end, fixes that.

Differential Revision: https://reviews.llvm.org/D52322

llvm-svn: 342760
2018-09-21 18:41:31 +00:00
JF Bastien
5e7bfbaecc [NFC] use bit_cast in PointerSumType
The code was already using union and memcpy to do this. Remove the memcpy. We can't just change the union because a reference to its member is returned.

llvm-svn: 342759
2018-09-21 18:35:32 +00:00
JF Bastien
5c6ce4adfa [ADT] restrict bit_cast to trivially-constructible To
Summary: As discussed in r341853 by blaikie, the reinterpret_cast was technically an aliasing violation. Restrict our bit_cast implementation to To which are trivially-constructible (and note the existing restriction to constexpr). Once we move to C++17 we can use a version of bit_cast without these restrictions, or if we care we can SFINAE a different implementation when To isn't trivially-constructible.

Originally landed in r342710 and reverted in r342711 because is_trivially_copyable is only in GCC 5.1 and later.

Reviewers: dblaikie, rsmith

Subscribers: dexonsmith, kristina, llvm-commits

Differential Revision: https://reviews.llvm.org/D52332

llvm-svn: 342739
2018-09-21 14:31:25 +00:00
Benjamin Kramer
90f7b06f3e [ADT] Hack around GCC 5.4 miscompiling Optional of enum.
I'm still not 100% sure that this is not UB lingering (Optional has UB
and should use std::launder, but we don't have std::launder)

llvm-svn: 342723
2018-09-21 11:38:35 +00:00