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Chandler Carruth a46e60eb2e [x86] Generalize BuildVectorSDNode::getConstantSplatValue to work for
any constant, constant FP, or undef splat and to tolerate any undef
lanes in a splat, then replace all uses of isSplatVector in X86's
lowering with it.

This fixes issues where undef lanes in an otherwise splat vector would
prevent the splat logic from firing. It is a touch more awkward to use
this interface, but it is much more accurate. Suggestions for better
interface structuring welcome.

With this fix, the code generated with the widening legalization
strategy for widen_cast-4.ll is *dramatically* improved as the special
lowering strategies for a v16i8 SRA kick in even though the high lanes
are undef.

We also get a slightly different choice for broadcasting an aligned
memory location, and use vpshufd instead of vbroadcastss. This looks
like a minor win for pipelining and domain crossing, but a minor loss
for the number of micro-ops. I suspect its a wash, but folks can easily
tweak the lowering if they want.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212324 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-04 08:11:49 +00:00
autoconf
bindings
cmake [CMake] Introduce LLVM_ENABLE_PLUGINS as an internal option. BUILD_SHARED_LIBS may not control enable/disable plugins. 2014-07-04 04:45:40 +00:00
docs
examples
include [x86] Generalize BuildVectorSDNode::getConstantSplatValue to work for 2014-07-04 08:11:49 +00:00
lib [x86] Generalize BuildVectorSDNode::getConstantSplatValue to work for 2014-07-04 08:11:49 +00:00
projects
test [x86] Generalize BuildVectorSDNode::getConstantSplatValue to work for 2014-07-04 08:11:49 +00:00
tools Sink undesirable LTO functions into the old C API 2014-07-04 00:58:41 +00:00
unittests
utils
.arcconfig
.clang-format
.gitignore
CMakeLists.txt [CMake] Introduce LLVM_SHLIB_OUTPUT_INTDIR. 2014-07-04 04:23:26 +00:00
CODE_OWNERS.TXT ARM Linux support 2014-04-02 23:03:28 +00:00
configure
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
Makefile
Makefile.common
Makefile.config.in
Makefile.rules
README.txt Trivial test commit. 2014-04-26 19:05:45 +00:00

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

This directory and its subdirectories contain source code for the Low Level
Virtual Machine, a toolkit for the construction of highly optimized compilers,
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Please see the documentation provided in docs/ for further
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