1 files changed, 45 insertions, 0 deletions
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index a18b030..da30ab8 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -413,6 +413,51 @@ public:
     llvm_unreachable("Target didn't implement TargetInstrInfo::insertSelect!");
   }
 
+  /// analyzeSelect - Analyze the given select instruction, returning true if
+  /// it cannot be understood. It is assumed that MI->isSelect() is true.
+  ///
+  /// When successful, return the controlling condition and the operands that
+  /// determine the true and false result values.
+  ///
+  ///   Result = SELECT Cond, TrueOp, FalseOp
+  ///
+  /// Some targets can optimize select instructions, for example by predicating
+  /// the instruction defining one of the operands. Such targets should set
+  /// Optimizable.
+  ///
+  /// @param         MI Select instruction to analyze.
+  /// @param Cond    Condition controlling the select.
+  /// @param TrueOp  Operand number of the value selected when Cond is true.
+  /// @param FalseOp Operand number of the value selected when Cond is false.
+  /// @param Optimizable Returned as true if MI is optimizable.
+  /// @returns False on success.
+  virtual bool analyzeSelect(const MachineInstr *MI,
+                             SmallVectorImpl<MachineOperand> &Cond,
+                             unsigned &TrueOp, unsigned &FalseOp,
+                             bool &Optimizable) const {
+    assert(MI && MI->isSelect() && "MI must be a select instruction");
+    return true;
+  }
+
+  /// optimizeSelect - Given a select instruction that was understood by
+  /// analyzeSelect and returned Optimizable = true, attempt to optimize MI by
+  /// merging it with one of its operands. Returns NULL on failure.
+  ///
+  /// When successful, returns the new select instruction. The client is
+  /// responsible for deleting MI.
+  ///
+  /// If both sides of the select can be optimized, PreferFalse is used to pick
+  /// a side.
+  ///
+  /// @param MI          Optimizable select instruction.
+  /// @param PreferFalse Try to optimize FalseOp instead of TrueOp.
+  /// @returns Optimized instruction or NULL.
+  virtual MachineInstr *optimizeSelect(MachineInstr *MI,
+                                       bool PreferFalse = false) const {
+    // This function must be implemented if Optimizable is ever set.
+    llvm_unreachable("Target must implement TargetInstrInfo::optimizeSelect!");
+  }
+
   /// copyPhysReg - Emit instructions to copy a pair of physical registers.
   virtual void copyPhysReg(MachineBasicBlock &MBB,
                            MachineBasicBlock::iterator MI, DebugLoc DL,