Add isRegSequence property.

This patch adds a new property: isRegSequence and the related target hooks: 
TargetIntrInfo::getRegSequenceInputs and 
TargetInstrInfo::getRegSequenceLikeInputs to specify that a target specific
instruction is a (kind of) REG_SEQUENCE.

<rdar://problem/12702965>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215394 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Fix broken test

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215395 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Clear lds bit on MUBUF instructions used for private stores

This bit was left uninitialized, which was causing some random failures
of piglit tests.

NOTE: This is a candidate for the 3.5 branch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215396 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Add check for low 32 bits of encoding to mubuf tests

There are no variable values like registers encoded in the low 32 bits of MUBUF
instructions, so it is relatively easy to check these bits, and it will
help prevent us from introducing encoding bugs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215397 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Add an _OFFEN variant MUBUF_STORE_* and use it for scratch writes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215398 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Add a ComplexPattern for selecting MUBUF _OFFSET variant

This saves us from having to copy a 64-bit 0 value into VGPRs for
BUFFER_* instruction which only have a 12-bit immediate offset.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215399 91177308-0d34-0410-b5e6-96231b3b80d8