[llvm-mca] Renamed BackendStatistics to RetireControlUnitStatistics.

Also, removed flag -verbose in favor of flag -retire-stats.

llvm-svn: 329794
diff --git a/llvm/docs/CommandGuide/llvm-mca.rst b/llvm/docs/CommandGuide/llvm-mca.rst
index 3d69e6d..1aafd3b 100644
--- a/llvm/docs/CommandGuide/llvm-mca.rst
+++ b/llvm/docs/CommandGuide/llvm-mca.rst
@@ -52,7 +52,7 @@
     __asm volatile("# LLVM-MCA-BEGIN foo");
     a += 42;
     __asm volatile("# LLVM-MCA-END");
-    a *= b;
+    a \*= b;
     return a;
   }
 
@@ -136,11 +136,6 @@
   queue. A value of zero for this flag is ignored, and the default store queue
   size is used instead.
 
-.. option:: -verbose
-
-  Enable verbose output. In particular, this flag enables a number of extra
-  statistics and performance counters for the retire control unit.
-
 .. option:: -timeline
 
   Enable the timeline view.
@@ -174,6 +169,10 @@
   Enable extra scheduler statistics. This view collects and analyzes instruction
   issue events. This view is disabled by default.
 
+.. option:: -retire-stats
+
+  Enable extra retire control unit statistics. This view is disabled by default.
+
 .. option:: -instruction-info
 
   Enable the instruction info view. This is enabled by default.