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LLVM backend for 6502
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Andrea Di Biagio 749e8fee34 [X86] Improve the lowering of packed shifts by constant build_vector. 
This patch teaches the backend how to efficiently lower logical and
arithmetic packed shifts on both SSE and AVX/AVX2 machines.

When possible, instead of scalarizing a vector shift, the backend should try
to expand the shift into a sequence of two packed shifts by immedate count
followed by a MOVSS/MOVSD.

Example
  (v4i32 (srl A, (build_vector < X, Y, Y, Y>)))

Can be rewritten as:
  (v4i32 (MOVSS (srl A, <Y,Y,Y,Y>), (srl A, <X,X,X,X>)))

[with X and Y ConstantInt]

The advantage is that the two new shifts from the example would be lowered into
X86ISD::VSRLI nodes. This is always cheaper than scalarizing the vector into
four scalar shifts plus four pairs of vector insert/extract.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206316 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-15 19:30:48 +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 AddLLVM: Mute the prefix "lib" in SHARED on win32. 2014-04-10 15:47:04 +00:00
docs Remove documentation for a deleted pass. 2014-04-12 02:09:17 +00:00
examples Fix warnings about an variable only used in asserts. 2014-03-06 06:35:46 +00:00
include Use unique_ptr to manage ownership of child Regions within llvm::Region 2014-04-15 18:32:43 +00:00
lib [X86] Improve the lowering of packed shifts by constant build_vector. 2014-04-15 19:30:48 +00:00
projects Remove projects/sample. 2014-03-12 22:40:22 +00:00
test [X86] Improve the lowering of packed shifts by constant build_vector. 2014-04-15 19:30:48 +00:00
tools verify-di: Implement DebugInfoVerifier 2014-04-15 16:27:38 +00:00
unittests verify-di: Implement DebugInfoVerifier 2014-04-15 16:27:38 +00:00
utils [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 07:20:03 +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 [CMake] Reformat, if(MSVC)...else()...endif() 2014-04-14 21:58:19 +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 Test commit. 2014-04-10 22:25:51 +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

README.txt 

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

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