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Tim Northover d0dbe02fd2 ARM & AArch64: make use of common cmpxchg idioms after expansion
The C and C++ semantics for compare_exchange require it to return a bool
indicating success. This gets mapped to LLVM IR which follows each cmpxchg with
an icmp of the value loaded against the desired value.

When lowered to ldxr/stxr loops, this extra comparison is redundant: its
results are implicit in the control-flow of the function.

This commit makes two changes: it replaces that icmp with appropriate PHI
nodes, and then makes sure earlyCSE is called after expansion to actually make
use of the opportunities revealed.

I've also added -{arm,aarch64}-enable-atomic-tidy options, so that
existing fragile tests aren't perturbed too much by the change. Many
of them either rely on undef/unreachable too pervasively to be
restored to something well-defined (particularly while making sure
they test the same obscure assert from many years ago), or depend on a
particular CFG shape, which is disrupted by SimplifyCFG.

rdar://problem/16227836

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209883 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-30 10:09:59 +00:00
autoconf Don't hard-code ld when extracting host linker version, use ${LD} if 2014-05-28 15:12:55 +00:00
bindings [OCaml] Add an ocamlfind package llvm.all_backends. 2014-05-01 21:00:52 +00:00
cmake AArch64/ARM64: move ARM64 into AArch64's place 2014-05-24 12:50:23 +00:00
docs Sync list of targets with configure's reality 2014-05-29 22:23:22 +00:00
examples Try to fix the msvc build. 2014-04-29 23:37:02 +00:00
include Allow vectorization of intrinsics such as powi,cttz and ctlz in Loop and SLP Vectorizer. 2014-05-30 04:31:24 +00:00
lib ARM & AArch64: make use of common cmpxchg idioms after expansion 2014-05-30 10:09:59 +00:00
projects Remove projects/sample. 2014-03-12 22:40:22 +00:00
test ARM & AArch64: make use of common cmpxchg idioms after expansion 2014-05-30 10:09:59 +00:00
tools [elf2yaml][ELF] Move Info field to the RelocationSection structure. This 2014-05-29 11:05:31 +00:00
unittests Use std::unique_ptr instead of OwningPtr in the MemoryBuffer unittests. 2014-05-18 21:01:46 +00:00
utils utils: Teach lldbDataFormatters to load automatically 2014-05-28 05:45:17 +00:00
.arcconfig Updated phabricator server. 2014-04-07 03:57:04 +00:00
.clang-format Test commit. 2014-03-02 13:08:46 +00:00
.gitignore Remove projects/sample. 2014-03-12 22:40:22 +00:00
CMakeLists.txt AArch64/ARM64: move ARM64 into AArch64's place 2014-05-24 12:50:23 +00:00
CODE_OWNERS.TXT ARM Linux support 2014-04-02 23:03:28 +00:00
configure Don't hard-code ld when extracting host linker version, use ${LD} if 2014-05-28 15:12:55 +00:00
CREDITS.TXT Update Credits. 2014-05-29 19:59:58 +00:00
LICENSE.TXT Remove projects/sample. 2014-03-12 22:40:22 +00:00
llvm.spec.in
LLVMBuild.txt Remove the very substantial, largely unmaintained legacy PGO 2013-10-02 15:42:23 +00:00
Makefile [configure/make] Propagate names of build host tools when making BuildTools 2014-03-25 21:45:41 +00:00
Makefile.common Makefile.common: Update a description, s/Source/SOURCES/ , according to MakefileGuide.html#control-variables . 2012-12-07 01:43:23 +00:00
Makefile.config.in Add a --enable-clang-plugin-support option to configure. 2014-03-10 16:58:35 +00:00
Makefile.rules autoconf: Fix libLLVM-Major-Minor-Patch.so symlink 2014-05-15 19:50:25 +00:00
README.txt Trivial test commit. 2014-04-26 19:05:45 +00:00

Low Level Virtual Machine (LLVM)
================================

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