Teach bugpoint to be a little bit smarter and avoid repeating work

llvm-svn: 13132

tools/bugpoint/Miscompilation.cpp

@@ -109,6 +109,10 @@ ReduceMiscompilingPasses::doTest(std::vector<const PassInfo*> &Prefix,
   }
   removeFile(BytecodeResult);  // No longer need the file on disk
 
+  // Don't check if there are no passes in the suffix.
+  if (Suffix.empty())
+    return NoFailure;
+  
   std::cout << "Checking to see if '" << getPassesString(Suffix)
             << "' passes compile correctly after the '"
             << getPassesString(Prefix) << "' passes: ";