Revert "Remove unnecessary check for Darwin. rdar://problem/16264854"

This breaks linux buildbots. Go figure.

llvm-svn: 203300
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 2062b61..81934e1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2837,7 +2837,7 @@
 void DwarfDebug::attachLowHighPC(DwarfCompileUnit *Unit, DIE *D,
                                  MCSymbol *Begin, MCSymbol *End) {
   Unit->addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
-  if (DwarfVersion < 4)
+  if (DwarfVersion < 4 || Triple(Asm->getTargetTriple()).isOSDarwin())
     Unit->addLabelAddress(D, dwarf::DW_AT_high_pc, End);
   else
     Unit->addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);