DAG: move sret demotion into most basic LowerCallTo implementation.

It looks like there are two versions of LowerCallTo here: the
SelectionDAGBuilder one is designed to operate on LLVM IR, and the
TargetLowering one in the case where everything is at DAG level.

Previously, only the SelectionDAGBuilder variant could handle demoting
an impossible return to sret semantics (before delegating to the
TargetLowering version), but this functionality is also useful for
certain libcalls (e.g. 128-bit operations on 32-bit x86).  So this
commit moves the sret handling down a level.

rdar://problem/17242889

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211155 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Handle X86 *.psad.* and *.pmadd.* intrinsics.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211156 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Implement 64bit SHL

v2: Use c++ style comment

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211157 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Implement 64bit SRL

v2: use C++ style comment

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211158 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Implement 64bit SRA

v2: Use capitalized variable name

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211159 91177308-0d34-0410-b5e6-96231b3b80d8