[fast-isel] Guard "exhastive" fast-isel output with -fast-isel-verbose2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146453 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index f626353..477ec80 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -63,6 +63,10 @@
 STATISTIC(NumDAGIselRetries,"Number of times dag isel has to try another path");
 
 #ifndef NDEBUG
+static cl::opt<bool>
+EnableFastISelVerbose2("fast-isel-verbose2", cl::Hidden,
+          cl::desc("Enable extra verbose messages in the \"fast\" "
+                   "instruction selector"));
   // Terminators
 STATISTIC(NumFastIselFailRet,"Fast isel fails on Ret");
 STATISTIC(NumFastIselFailBr,"Fast isel fails on Br");
@@ -1086,7 +1090,8 @@
         }
 
 #ifndef NDEBUG
-        collectFailStats(Inst);
+        if (EnableFastISelVerbose2)
+          collectFailStats(Inst);
 #endif
 
         // Then handle certain instructions as single-LLVM-Instruction blocks.