[llvm-commits] [llvm] r56968 - in /llvm/trunk: include/llvm/CodeGen/MachineBasicBlock.h lib/CodeGen/MachineBasicBlock.cpp

[Dan Gohman]

Author: djg
Date: Thu Oct  2 17:09:09 2008
New Revision: 56968

URL: http://llvm.org/viewvc/llvm-project?rev=56968&view=rev
Log:
Add a new MachineBasicBlock utility function, isLayoutSuccessor, that
can be used when deciding if a block can transfer control to another
via a fall-through instead of a branch.

Modified:
    llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
    llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp

Modified: llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h?rev=56968&r1=56967&r2=56968&view=diff

==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h Thu Oct  2 17:09:09 2008
@@ -234,6 +234,13 @@
   /// block.
   bool isSuccessor(MachineBasicBlock *MBB) const;
 
+  /// isLayoutSuccessor - Return true if the specified MBB will be emitted
+  /// immediately after this block, such that if this block exits by
+  /// falling through, control will transfer to the specified MBB. Note
+  /// that MBB need not be a successor at all, for example if this block
+  /// ends with an unconditional branch to some other block.
+  bool isLayoutSuccessor(MachineBasicBlock *MBB) const;
+
   /// getFirstTerminator - returns an iterator to the first terminator
   /// instruction of this basic block. If a terminator does not exist,
   /// it returns end()

Modified: llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp?rev=56968&r1=56967&r2=56968&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp Thu Oct  2 17:09:09 2008
@@ -254,6 +254,11 @@
   return I != Successors.end();
 }
 
+bool MachineBasicBlock::isLayoutSuccessor(MachineBasicBlock *MBB) const {
+  MachineFunction::const_iterator I(this);
+  return next(I) == MachineFunction::const_iterator(MBB);
+}
+
 /// removeFromParent - This method unlinks 'this' from the containing function,
 /// and returns it, but does not delete it.
 MachineBasicBlock *MachineBasicBlock::removeFromParent() {