Marking debug info intrinsics as not touching memory

caused them to be considered trivially dead.  Fix this.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65979 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/Local.cpp

@@ -159,6 +159,9 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB) {
 bool llvm::isInstructionTriviallyDead(Instruction *I) {
   if (!I->use_empty() || isa<TerminatorInst>(I)) return false;
 
+  // We don't want debug info removed by anything this general.
+  if (isa<DbgInfoIntrinsic>(I)) return false;
+    
   if (!I->mayWriteToMemory())
     return true;