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Tim Northover badb137729 ARM: expand atomic ldrex/strex loops in IR
The previous situation where ATOMIC_LOAD_WHATEVER nodes were expanded
at MachineInstr emission time had grown to be extremely large and
involved, to account for the subtly different code needed for the
various flavours (8/16/32/64 bit, cmpxchg/add/minmax).

Moving this transformation into the IR clears up the code
substantially, and makes future optimisations much easier:

1. an atomicrmw followed by using the *new* value can be more
   efficient. As an IR pass, simple CSE could handle this
   efficiently.
2. Making use of cmpxchg success/failure orderings only has to be done
   in one (simpler) place.
3. The common "cmpxchg; did we store?" idiom can be exposed to
   optimisation.

I intend to gradually improve this situation within the ARM backend
and make sure there are no hidden issues before moving the code out
into CodeGen to be shared with (at least ARM64/AArch64, though I think
PPC & Mips could benefit too).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205525 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-03 11:44:58 +00:00
autoconf ARM64: initial backend import 2014-03-29 10:18:08 +00:00
bindings [python-bindings] Remove some cruft that snuck in. 2014-02-23 04:43:26 +00:00
cmake ARM64: initial backend import 2014-03-29 10:18:08 +00:00
docs Stack map docs. Remove some stray markup. 2014-04-03 07:08:21 +00:00
examples Fix warnings about an variable only used in asserts. 2014-03-06 06:35:46 +00:00
include Handle getting UnknownAddressOrSize or section_end(). 2014-04-03 03:57:03 +00:00
lib ARM: expand atomic ldrex/strex loops in IR 2014-04-03 11:44:58 +00:00
projects Remove projects/sample. 2014-03-12 22:40:22 +00:00
test ARM: expand atomic ldrex/strex loops in IR 2014-04-03 11:44:58 +00:00
tools Revert "Fix a nomenclature error in llvm-nm." 2014-04-03 00:19:35 +00:00
unittests MCJIT: ensure that cygwin is identified properly 2014-03-31 23:42:23 +00:00
utils lit: Set a base directory for compiler-rt tests 2014-03-31 23:14:10 +00:00
.arcconfig
.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 Add ability to disable building LLVM utils 2014-04-02 22:49:58 +00:00
CODE_OWNERS.TXT ARM Linux support 2014-04-02 23:03:28 +00:00
configure ARM64: initial backend import 2014-03-29 10:18:08 +00:00
CREDITS.TXT Fix documentation typos 2013-12-20 00:33:39 +00:00
LICENSE.TXT Remove projects/sample. 2014-03-12 22:40:22 +00:00
llvm.spec.in
LLVMBuild.txt
Makefile [configure/make] Propagate names of build host tools when making BuildTools 2014-03-25 21:45:41 +00:00
Makefile.common
Makefile.config.in Add a --enable-clang-plugin-support option to configure. 2014-03-10 16:58:35 +00:00
Makefile.rules Use -std=gnu++11 on cygwin and mingw. 2014-03-12 20:01:15 +00:00
README.txt Revert "Test commit to check e-mail address. Please discard this." 2013-10-04 10:59:13 +00:00

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