[WinEH] Add some support for code generating catchpad

We can now run 32-bit programs with empty catch bodies.  The next step
is to change PEI so that we get funclet prologues and epilogues.

llvm-svn: 246235
diff --git a/llvm/lib/Target/X86/X86MCInstLower.cpp b/llvm/lib/Target/X86/X86MCInstLower.cpp
index 36c7402..c190bbe 100644
--- a/llvm/lib/Target/X86/X86MCInstLower.cpp
+++ b/llvm/lib/Target/X86/X86MCInstLower.cpp
@@ -531,6 +531,12 @@
     break;
   }
 
+  case X86::CATCHRET: {
+    OutMI = MCInst();
+    OutMI.setOpcode(getRetOpcode(AsmPrinter.getSubtarget()));
+    break;
+  }
+
   // TAILJMPd, TAILJMPd64 - Lower to the correct jump instructions.
   case X86::TAILJMPr:
   case X86::TAILJMPd: