Add lowering support for llvm.experimental.deoptimize

Summary:
Only adds support for "naked" calls to llvm.experimental.deoptimize.
Support for round-tripping through RewriteStatepointsForGC will come
as a separate patch (should be simpler than this one).

Reviewers: reames

Subscribers: sanjoy, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D18429

llvm-svn: 264329
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index d714ad1..747950f 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -435,6 +435,8 @@
     Names[RTLIB::FPEXT_F16_F32] = "__extendhfsf2";
     Names[RTLIB::FPROUND_F32_F16] = "__truncsfhf2";
   }
+
+  Names[RTLIB::DEOPTIMIZE] = "__llvm_deoptimize";
 }
 
 /// InitLibcallCallingConvs - Set default libcall CallingConvs.