Add detection of OS X relocatable SDK to compiler-rt as a lit.util function

Clang's lit cfg already detects the currently selected SDK via
"xcrun --show-sdk-path". The same thing should be done for compiler-rt tests,
to make them work on recent OS X versions. Instead of duplicating the detection
code, this patch extracts the detection function into a lit.util method.

Patch by Kuba Brecka (kuba.brecka@gmail.com),
reviewed at http://reviews.llvm.org/D4072


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210534 91177308-0d34-0410-b5e6-96231b3b80d8
[AArch64] Emit .ident compiler version attribute.
Patch by Ana Pazos<apazos@codeaurora.org>!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210535 91177308-0d34-0410-b5e6-96231b3b80d8
[PPC64LE] Recognize shufflevector patterns for little endian

Various masks on shufflevector instructions are recognizable as
specific PowerPC instructions (vector pack, vector merge, etc.).
There is existing code in PPCISelLowering.cpp to recognize the correct
patterns for big endian code.  The masks for these instructions are
different for little endian code due to the big-endian numbering
employed by these instructions.  This patch adds the recognition code
for little endian.

I've added a new test case test/CodeGen/PowerPC/vec_shuffle_le.ll for
this.  The existing recognizer test (vec_shuffle.ll) is unnecessarily
verbose and difficult to read, so I felt it was better to add a new
test rather than modify the old one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210536 91177308-0d34-0410-b5e6-96231b3b80d8