From: Chris Lattner <sabre@nondot.org>
Date: Wed, 19 Jan 2005 06:53:02 +0000 (+0000)
Subject: Add a new method, described in the comment.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d7e2fe40e42dffa04a770191c3414446d5e8c30a;p=oota-llvm.git

Add a new method, described in the comment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19683 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index 855ce86ed08..d5237f2f7cc 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -177,6 +177,18 @@ public:
     return 0;
   }
 
+  /// commuteInstruction - If a target has any instructions that are commutable,
+  /// but require converting to a different instruction or making non-trivial
+  /// changes to commute them, this method can overloaded to do this.  The
+  /// default implementation of this method simply swaps the first two operands
+  /// of MI and returns it.
+  ///
+  /// If a target wants to make more aggressive changes, they can construct and
+  /// return a new machine instruction.  If an instruction cannot commute, it
+  /// can also return null.
+  ///
+  virtual MachineInstr *commuteInstruction(MachineInstr *MI) const;
+
   /// Insert a goto (unconditional branch) sequence to TMBB, at the
   /// end of MBB
   virtual void insertGoto(MachineBasicBlock& MBB,