enable jump threading pass by default.  This causes no miscompilations 
and can significantly shrinkify some code, particularly from C++ land.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50025 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index ca206cf..4b7dbf5 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -267,6 +267,7 @@
 
   addPass(PM, createTailDuplicationPass());      // Simplify cfg by copying code
   addPass(PM, createInstructionCombiningPass()); // Cleanup for scalarrepl.
+  addPass(PM, createJumpThreadingPass());        // Thread jumps.
   addPass(PM, createCFGSimplificationPass());    // Merge & remove BBs
   addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
   addPass(PM, createInstructionCombiningPass()); // Combine silly seq's