David Blaikie 434bbb1a68 Assigning to a local object in a return statement prevents copy elision. NFC. ...

I added a diagnostic along the lines of `-Wpessimizing-move` to detect `return x = y` suppressing copy elision, but I don't know if the diagnostic is really worth it. Anyway, here are the places where my diagnostic reported that copy elision would have been possible if not for the assignment.

P1155R1 in the post-San-Diego WG21 (C++ committee) mailing discusses whether WG21 should fix this pitfall by just changing the core language to permit copy elision in cases like these.

(Kona update: The bulk of P1155 is proceeding to CWG review, but specifically *not* the parts that explored the notion of permitting copy-elision in these specific cases.)

Reviewed By: dblaikie

Author: Arthur O'Dwyer

Differential Revision: https://reviews.llvm.org/D54885

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359236 91177308-0d34-0410-b5e6-96231b3b80d8

2019-04-25 20:09:00 +00:00

..

AddressSanitizer.cpp

[CommandLine] Provide parser<unsigned long> instantiation to allow cl::opt<uint64_t> on LP64 platforms

2019-04-24 02:40:20 +00:00

BoundsChecking.cpp

Add a 'dynamic' parameter to the objectsize intrinsic

2019-01-30 20:34:35 +00:00

CFGMST.h

Use llvm::stable_sort

2019-04-23 14:51:27 +00:00

CGProfile.cpp

Update the file headers across all of the LLVM projects in the monorepo

2019-01-19 08:50:56 +00:00

CMakeLists.txt

Remove esan.

2019-03-11 20:23:40 +00:00

ControlHeightReduction.cpp

Use llvm::stable_sort

2019-04-23 14:51:27 +00:00

DataFlowSanitizer.cpp

Add "const" in GetUnderlyingObjects. NFC

2019-04-24 06:55:50 +00:00

GCOVProfiling.cpp

[opaque pointer types] Pass value type to GetElementPtr creation.

2019-02-01 20:44:47 +00:00

HWAddressSanitizer.cpp

[CommandLine] Provide parser<unsigned long> instantiation to allow cl::opt<uint64_t> on LP64 platforms

2019-04-24 02:40:20 +00:00

IndirectCallPromotion.cpp

Change some dyn_cast to more apropriate isa. NFC

2019-04-05 16:16:23 +00:00

InstrOrderFile.cpp

Try to fix NetBSD buildbot breakage introduced in D57463.

2019-03-01 15:25:24 +00:00

InstrProfiling.cpp

[InstrProf] Use separate comdat group for data and counters

2019-02-27 23:38:44 +00:00

Instrumentation.cpp

Assigning to a local object in a return statement prevents copy elision. NFC.

2019-04-25 20:09:00 +00:00

LLVMBuild.txt

Update the file headers across all of the LLVM projects in the monorepo

2019-01-19 08:50:56 +00:00

MaximumSpanningTree.h

Use llvm::stable_sort

2019-04-23 14:51:27 +00:00

MemorySanitizer.cpp

[CommandLine] Provide parser<unsigned long> instantiation to allow cl::opt<uint64_t> on LP64 platforms

2019-04-24 02:40:20 +00:00

PGOInstrumentation.cpp

The error message for mismatched value sites is very cryptic.

2019-04-23 22:26:55 +00:00

PGOMemOPSizeOpt.cpp

Move DomTreeUpdater from IR to Analysis

2019-02-06 02:52:52 +00:00

SanitizerCoverage.cpp

[SanitizerCoverage] Avoid splitting critical edges when destination is a basic block containing unreachable

2019-03-12 18:20:25 +00:00

ThreadSanitizer.cpp

[opaque pointer types] Add a FunctionCallee wrapper type, and use it.

2019-02-01 02:28:03 +00:00