move isOnlyReachableByFallthrough out of MachineBasicBlock into AsmPrinter,

and add a sparc implementation that knows about delay slots.  Patch by
Nathan Keynes!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96492 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/AsmPrinter.h

@@ -356,6 +356,11 @@ namespace llvm {
     /// printOffset - This is just convenient handler for printing offsets.
     void printOffset(int64_t Offset) const;
 
+    /// isBlockOnlyReachableByFallthough - Return true if the basic block has
+    /// exactly one predecessor and the control transfer mechanism between
+    /// the predecessor and this block is a fall-through.
+    virtual bool isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const;
+
   private:
 
     /// processDebugLoc - Processes the debug information of each machine