it is ok to dce stacksave.

llvm-svn: 25295
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 8f0f7e8..4e3b3e97 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -296,6 +296,7 @@
       default: break;
       case Intrinsic::returnaddress:
       case Intrinsic::frameaddress:
+      case Intrinsic::stacksave:
       case Intrinsic::isunordered:
       case Intrinsic::ctpop:
       case Intrinsic::ctlz: