[PowerPC] Support powerpc64le as a syntax-checking target.

This patch provides basic support for powerpc64le as an LLVM target.
However, use of this target will not actually generate little-endian
code.  Instead, use of the target will cause the correct little-endian
built-in defines to be generated, so that code that tests for
__LITTLE_ENDIAN__, for example, will be correctly parsed for
syntax-only testing.  Code generation will otherwise be the same as
powerpc64 (big-endian), for now.

The patch leaves open the possibility of creating a little-endian
PowerPC64 back end, but there is no immediate intent to create such a
thing.

The new test case variant ensures that correct built-in defines for
little-endian code are generated.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@187180 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index 91b6bc1..028ba62 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -736,6 +736,10 @@
     case llvm::Triple::ppc64:
       llvm::outs() << "ppc64;@m64" << "\n";
       break;
+
+    case llvm::Triple::ppc64le:
+      llvm::outs() << "ppc64le;@m64" << "\n";
+      break;
     }
     return false;
   }
@@ -758,6 +762,10 @@
     case llvm::Triple::ppc64:
       llvm::outs() << "ppc64" << "\n";
       break;
+
+    case llvm::Triple::ppc64le:
+      llvm::outs() << "ppc64le" << "\n";
+      break;
     }
     return false;
   }