Replace "fallthrough" comments with LLVM_FALLTHROUGH

This is a mechanical change of comments in switches like fallthrough,
fall-through, or fall-thru to use the LLVM_FALLTHROUGH macro instead.

llvm-svn: 278902
diff --git a/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp b/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
index 4181775..48b1837 100644
--- a/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
+++ b/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
@@ -1571,7 +1571,8 @@
         return false;
       }
     }
-  // Fall-through to process non-register-name identifiers as expression.
+    // Fall-through to process non-register-name identifiers as expression.
+    LLVM_FALLTHROUGH;
   // All other expressions
   case AsmToken::LParen:
   case AsmToken::Plus:
@@ -1644,7 +1645,7 @@
         break;
       }
     }
-    // Fall-through..
+    LLVM_FALLTHROUGH;
 
     default:
       return Error(S, "invalid memory operand");