New EH representation for MSVC compatibility

This introduces new instructions neccessary to implement MSVC-compatible
exception handling support.  Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.

Differential Revision: http://reviews.llvm.org/D11097

llvm-svn: 243766
diff --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index 4d3a708..c625b0f 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -539,9 +539,9 @@
     return;
   }
 
-  if (isa<InvokeInst>(TI)) {
-    // Invoke instructions successors are always executable.
-    Succs[0] = Succs[1] = true;
+  // Unwinding instructions successors are always executable.
+  if (TI.isExceptional()) {
+    Succs.assign(TI.getNumSuccessors(), true);
     return;
   }
 
@@ -605,8 +605,8 @@
     return BI->getSuccessor(CI->isZero()) == To;
   }
 
-  // Invoke instructions successors are always executable.
-  if (isa<InvokeInst>(TI))
+  // Unwinding instructions successors are always executable.
+  if (TI->isExceptional())
     return true;
 
   if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {