Chandler Carruth fb1293fd4c [x86] Teach the target shuffle mask extraction to recognize unary forms ... of normally binary shuffle instructions like PUNPCKL and MOVLHPS. This detects cases where a single register is used for both operands making the shuffle behave in a unary way. We detect this and adjust the mask to use the unary form which allows the existing DAG combine for shuffle instructions to actually work at all. As a consequence, this uncovered a number of obvious bugs in the existing DAG combine which are fixed. It also now canonicalizes several shuffles even with the existing lowering. These typically are trying to match the shuffle to the domain of the input where before we only really modeled them with the floating point variants. All of the cases which change to an integer shuffle here have something in the integer domain, so there are no more or fewer domain crosses here AFAICT. Technically, it might be better to go from a GPR directly to the floating point domain, but detecting floating point *outputs* despite integer inputs is a lot more code and seems unlikely to be worthwhile in practice. If folks are seeing domain-crossing regressions here though, let me know and I can hack something up to fix it. Also as a consequence, a bunch of missed opportunities to form pshufb now can be formed. Notably, splats of i8s now form pshufb. Interestingly, this improves the existing splat lowering too. We go from 3 instructions to 1. Yes, we may tie up a register, but it seems very likely to be worth it, especially if splatting the 0th byte (the common case) as then we can use a zeroed register as the mask. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214625 91177308-0d34-0410-b5e6-96231b3b80d8		2014-08-02 10:27:38 +00:00
..
Analysis
Assembler	verify-uselistorder: Change the default -num-shuffles=5	2014-07-31 18:46:24 +00:00
Bindings
Bitcode	UseListOrder: Fix blockaddress use-list order	2014-08-01 22:27:19 +00:00
BugPoint
CodeGen	[x86] Teach the target shuffle mask extraction to recognize unary forms	2014-08-02 10:27:38 +00:00
DebugInfo	Cleanup this test some more.	2014-08-01 23:01:32 +00:00
ExecutionEngine
Feature	Use "weak alias" instead of "alias weak"	2014-07-30 22:51:54 +00:00
FileCheck
Instrumentation	[ASan] Use metadata to pass source-level information from Clang to ASan.	2014-08-02 00:35:50 +00:00
Integer
JitListener
Linker	Use "weak alias" instead of "alias weak"	2014-07-30 22:51:54 +00:00
LTO
MC	Allow only disassembling of M-class MSR masks that the assembler knows how to assemble back.	2014-08-01 12:42:11 +00:00
Object	Use "weak alias" instead of "alias weak"	2014-07-30 22:51:54 +00:00
Other
TableGen
tools	InstrProf: Allow multiple functions with the same name	2014-08-01 22:50:07 +00:00
Transforms	Add diagnostics to the vectorizer cost model.	2014-08-02 00:14:03 +00:00
Unit
Verifier	Use "weak alias" instead of "alias weak"	2014-07-30 22:51:54 +00:00
YAMLParser
.clang-format
CMakeLists.txt	Rename llvm-uselistorder => verify-uselistorder	2014-07-30 17:11:27 +00:00
lit.cfg	Rename llvm-uselistorder => verify-uselistorder	2014-07-30 17:11:27 +00:00
lit.site.cfg.in
Makefile
Makefile.tests
TestRunner.sh