[PPC64LE] Add test case for r210282 commit

Chandler correctly pointed out that I need an LLVM IR test for
r210282, which modified the vperm -> shuffle transform for little
endian PowerPC.  This patch provides that test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210297 91177308-0d34-0410-b5e6-96231b3b80d8
Correctly set the comdat symbol on COFF.

We extended the .section syntax to allow multiple sections with the
same name but different comdats, but currently we don't make sure that
the output section has that comdat symbol.

That happens to work with the code llc produces currently because it looks like

.section secName, "dr", one_only, "COMDATSym"
.globl COMDATSym
COMDATSym:
....

but that is not very friendly to anyone coding in assembly or even to
llc once we get comdat support in the IR.

This patch changes the coff object writer to make sure the comdat symbol is
output just after the section symbol, as required by the coff spec.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210298 91177308-0d34-0410-b5e6-96231b3b80d8
Fix null dereference with -debug-only=dwarfdebug

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210299 91177308-0d34-0410-b5e6-96231b3b80d8
Fix markup for -debug-only option

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210300 91177308-0d34-0410-b5e6-96231b3b80d8