Reid Kleckner 73e1a13fdc [IR] De-virtualize ~Value to save a vptr ... Summary: Implements PR889 Removing the virtual table pointer from Value saves 1% of RSS when doing LTO of llc on Linux. The impact on time was positive, but too noisy to conclusively say that performance improved. Here is a link to the spreadsheet with the original data: https://docs.google.com/spreadsheets/d/1F4FHir0qYnV0MEp2sYYp_BuvnJgWlWPhWOwZ6LbW7W4/edit?usp=sharing This change makes it invalid to directly delete a Value, User, or Instruction pointer. Instead, such code can be rewritten to a null check and a call Value::deleteValue(). Value objects tend to have their lifetimes managed through iplist, so for the most part, this isn't a big deal. However, there are some places where LLVM deletes values, and those places had to be migrated to deleteValue. I have also created llvm::unique_value, which has a custom deleter, so it can be used in place of std::unique_ptr<Value>. I had to add the "DerivedUser" Deleter escape hatch for MemorySSA, which derives from User outside of lib/IR. Code in IR cannot include MemorySSA headers or call the MemoryAccess object destructors without introducing a circular dependency, so we need some level of indirection. Unfortunately, no class derived from User may have any virtual methods, because adding a virtual method would break User::getHungOffOperands(), which assumes that it can find the use list immediately prior to the User object. I've added a static_assert to the appropriate OperandTraits templates to help people avoid this trap. Reviewers: chandlerc, mehdi_amini, pete, dberlin, george.burgess.iv Reviewed By: chandlerc Subscribers: krytarowski, eraman, george.burgess.iv, mzolotukhin, Prazek, nlewycky, hans, inglorion, pcc, tejohnson, dberlin, llvm-commits Differential Revision: https://reviews.llvm.org/D31261 llvm-svn: 303362		2017-05-18 17:24:10 +00:00
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BBVectorize.cpp	[SystemZ] TargetTransformInfo cost functions implemented.	2017-04-12 11:49:08 +00:00
CMakeLists.txt	[CMake] NFC. Updating CMake dependency specifications	2016-11-17 04:36:50 +00:00
LLVMBuild.txt
LoadStoreVectorizer.cpp	[KnownBits] Add bit counting methods to KnownBits struct and use them where possible	2017-05-12 17:20:30 +00:00
LoopVectorize.cpp	Revert 303174, 303176, and 303178	2017-05-16 15:50:30 +00:00
SLPVectorizer.cpp	[IR] De-virtualize ~Value to save a vptr	2017-05-18 17:24:10 +00:00
Vectorize.cpp