llvm-project/llvm
Ahmed Bougacha 07a844d758 [AArch64] Emit clrex in the expanded cmpxchg fail block.
In the comparison failure block of a cmpxchg expansion, the initial
ldrex/ldxr will not be followed by a matching strex/stxr.
On ARM/AArch64, this unnecessarily ties up the execution monitor,
which might have a negative performance impact on some uarchs.

Instead, release the monitor in the failure block.
The clrex instruction was designed for this: use it.

Also see ARMARM v8-A B2.10.2:
"Exclusive access instructions and Shareable memory locations".

Differential Revision: http://reviews.llvm.org/D13033

llvm-svn: 248291
2015-09-22 17:21:44 +00:00
..
autoconf Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
bindings [bindings] Update Go bindings to DIBuilder 2015-09-06 02:22:15 +00:00
cmake [CMake] Adding ALWAYS_GENERATE option to symlink utility functions. 2015-09-18 21:08:32 +00:00
docs Nit cleanup in LangRef about dereferenceable metadata 2015-09-18 12:07:10 +00:00
examples Fix typo and test commit 2015-09-18 21:15:45 +00:00
include [AArch64] Emit clrex in the expanded cmpxchg fail block. 2015-09-22 17:21:44 +00:00
lib [AArch64] Emit clrex in the expanded cmpxchg fail block. 2015-09-22 17:21:44 +00:00
projects
resources
test [AArch64] Emit clrex in the expanded cmpxchg fail block. 2015-09-22 17:21:44 +00:00
tools Fix a typo. 2015-09-22 15:31:14 +00:00
unittests Simplify SmallBitVector::applyMask by consolidating common code for 32- and 64-bit builds 2015-09-18 15:08:24 +00:00
utils Remove extra 'nullptr' entry from an array in tablegen register info file. It should never have been accessed. 2015-09-22 05:37:16 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore Minor updates to gitignore so that symlinks are ignored in the projects dir. 2015-07-07 20:24:58 +00:00
CMakeLists.txt [CMake] [Darwin] Need to set lto_library on CMAKE_MODULE_LINKER_FLAGS as well 2015-09-11 18:39:19 +00:00
CODE_OWNERS.TXT CODE_OWNERS.TXT is supposed to be sorted by surname 2015-09-07 00:41:40 +00:00
CREDITS.TXT
LICENSE.TXT
LLVMBuild.txt
Makefile
Makefile.common
Makefile.config.in We're actually -Wmissing-field-initializers clean thanks to the cmake 2015-08-07 16:44:47 +00:00
Makefile.rules We're actually -Wmissing-field-initializers clean thanks to the cmake 2015-08-07 16:44:47 +00:00
README.txt
configure Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
llvm.spec.in [Sparc] Implement i64 load/store support for 32-bit sparc. 2015-08-10 19:11:39 +00:00

README.txt

Low Level Virtual Machine (LLVM)
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