LLVM backend for 6502
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Chandler Carruth 1c8db50a9a Port the SSAUpdater-based promotion logic from the old SROA pass to the
new one, and add support for running the new pass in that mode and in
that slot of the pass manager. With this the new pass can completely
replace the old one within the pipeline.

The strategy for enabling or disabling the SSAUpdater logic is to do it
by making the requirement of the domtree analysis optional. By default,
it is required and we get the standard mem2reg approach. This is usually
the desired strategy when run in stand-alone situations. Within the
CGSCC pass manager, we disable requiring of the domtree analysis and
consequentially trigger fallback to the SSAUpdater promotion.

In theory this would allow the pass to re-use a domtree if one happened
to be available even when run in a mode that doesn't require it. In
practice, it lets us have a single pass rather than two which was
simpler for me to wrap my head around.

There is a hidden flag to force the use of the SSAUpdater code path for
the purpose of testing. The primary testing strategy is just to run the
existing tests through that path. One notable difference is that it has
custom code to handle lifetime markers, and one of the tests has been
enhanced to exercise that code.

This has survived a bootstrap and the test suite without serious
correctness issues, however my run of the test suite produced *very*
alarming performance numbers. I don't entirely understand or trust them
though, so more investigation is on-going.

To aid my understanding of the performance impact of the new SROA now
that it runs throughout the optimization pipeline, I'm enabling it by
default in this commit, and will disable it again once the LNT bots have
picked up one iteration with it. I want to get those bots (which are
much more stable) to evaluate the impact of the change before I jump to
any conclusions.

NOTE: Several Clang tests will fail because they run -O3 and check the
result's order of output. They'll go back to passing once I disable it
again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163965 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-15 11:43:14 +00:00
autoconf Temporarily revert this to bring back the bots. 2012-08-28 01:17:46 +00:00
bindings add support for ocaml 3.12 2012-09-02 14:42:56 +00:00
cmake CMake toolchain file for Android NDK. 2012-09-11 11:54:27 +00:00
docs Patch by Sean Silva! 2012-09-13 23:51:08 +00:00
examples
include Port the SSAUpdater-based promotion logic from the old SROA pass to the 2012-09-15 11:43:14 +00:00
lib Port the SSAUpdater-based promotion logic from the old SROA pass to the 2012-09-15 11:43:14 +00:00
projects Enable recursing into the compiler-rt projcet with the CMake build. 2012-08-29 00:38:02 +00:00
runtime libprofile: [CMake] Let libprofile_rt be not loadable_module but shared library. Autoconf's one does so. 2012-08-29 00:37:51 +00:00
test Port the SSAUpdater-based promotion logic from the old SROA pass to the 2012-09-15 11:43:14 +00:00
tools Don't include stdint.h directly. 2012-09-06 22:55:11 +00:00
unittests cmake: Fix file path. 2012-09-14 23:36:56 +00:00
utils Revert r163878 as it breaks on targets with alternate register names. Such targets do not exist in the main tree so this was not noticed. 2012-09-15 01:22:42 +00:00
.gitignore Ignore the documentation-suggested location for compile_commands.json 2012-08-21 19:23:30 +00:00
CMakeLists.txt enable cross compilation with cmake 2012-08-20 19:56:52 +00:00
CODE_OWNERS.TXT
configure Temporarily revert this to bring back the bots. 2012-08-28 01:17:46 +00:00
CREDITS.TXT Add IRC handle. 2012-09-11 07:50:40 +00:00
LICENSE.TXT
llvm.spec.in
LLVMBuild.txt
Makefile darwin/cross-build: Unset SDKROOT when building BuildTools. 2012-08-22 22:01:01 +00:00
Makefile.common
Makefile.config.in Temporarily revert this to bring back the bots. 2012-08-28 01:17:46 +00:00
Makefile.rules Temporarily revert this to bring back the bots. 2012-08-28 01:17:46 +00:00
README.txt

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

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