Implement the convertToThreeAddress method, add support for inverting JP/JNP
branches.
llvm-svn: 19247
diff --git a/llvm/lib/Target/X86/X86InstrInfo.h b/llvm/lib/Target/X86/X86InstrInfo.h
index 72eee6b..c8f8716f 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.h
+++ b/llvm/lib/Target/X86/X86InstrInfo.h
@@ -179,6 +179,18 @@
unsigned& sourceReg,
unsigned& destReg) const;
+ /// convertToThreeAddress - This method must be implemented by targets that
+ /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
+ /// may be able to convert a two-address instruction into a true
+ /// three-address instruction on demand. This allows the X86 target (for
+ /// example) to convert ADD and SHL instructions into LEA instructions if they
+ /// would require register copies due to two-addressness.
+ ///
+ /// This method returns a null pointer if the transformation cannot be
+ /// performed, otherwise it returns the new instruction.
+ ///
+ virtual MachineInstr *convertToThreeAddress(MachineInstr *TA) const;
+
/// Insert a goto (unconditional branch) sequence to TMBB, at the
/// end of MBB
virtual void insertGoto(MachineBasicBlock& MBB,