Chandler Carruth 7fcb422bb2 [x86] Revert r212324 which was too aggressive w.r.t. allowing undef ... lanes in vector splats. The core problem here is that undef lanes can't *unilaterally* be considered to contribute to splats. Their handling needs to be more cautious. There is also a reported failure of the nightly testers (thanks Tobias!) that may well stem from the same core issue. I'm going to fix this theoretical issue, factor the APIs a bit better, and then verify that I don't see anything bad with Tobias's reduction from the test suite before recommitting. Original commit message for r212324: [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@212475 91177308-0d34-0410-b5e6-96231b3b80d8		2014-07-07 19:03:32 +00:00
..
Analysis	fixed typos in comments	2014-07-06 23:24:53 +00:00
AsmParser	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
Bitcode	Fix a bug in the conversion to ErrorOr.	2014-07-04 20:05:56 +00:00
CodeGen	[x86] Revert r212324 which was too aggressive w.r.t. allowing undef	2014-07-07 19:03:32 +00:00
DebugInfo	Revert "Introduce a string_ostream string builder facilty"	2014-06-26 22:52:05 +00:00
ExecutionEngine	ExecutionEngine::create(): fix interpreter fallback when JIT is unavailable	2014-07-01 03:18:49 +00:00
IR	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
IRReader	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
LineEditor	[CMake] Use LINK_LIBS instead of target_link_libraries().	2014-02-26 06:41:29 +00:00
Linker	Include <tuple> to make buildbots happy	2014-06-27 18:38:12 +00:00
LTO	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
MC	This only needs a StringRef.	2014-07-06 14:17:29 +00:00
Object	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
Option	Revert "Introduce a string_ostream string builder facilty"	2014-06-26 22:52:05 +00:00
ProfileData	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
Support	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
TableGen	Update the MemoryBuffer API to use ErrorOr.	2014-07-06 17:43:13 +00:00
Target	[x86] Revert r212324 which was too aggressive w.r.t. allowing undef	2014-07-07 19:03:32 +00:00
Transforms	Make helper functions static.	2014-07-07 14:47:51 +00:00
CMakeLists.txt	ProfileData: Introduce the InstrProfReader interface and a text reader	2014-03-21 17:24:48 +00:00
LLVMBuild.txt	ProfileData: Introduce the InstrProfReader interface and a text reader	2014-03-21 17:24:48 +00:00
Makefile	ProfileData: Introduce the InstrProfReader interface and a text reader	2014-03-21 17:24:48 +00:00