[mips] Define a helper function which creates an instruction with the same

operands as the prototype instruction but with a different opcode.

llvm-svn: 181714

lib/Target/Mips/MipsInstrInfo.cpp

@@ -282,3 +282,16 @@ unsigned MipsInstrInfo::GetInstSizeInBytes(const MachineInstr *MI) const {
   }
   }
 }
+
+MachineInstrBuilder
+MipsInstrInfo::genInstrWithNewOpc(unsigned NewOpc,
+                                  MachineBasicBlock::iterator I) const {
+  MachineInstrBuilder MIB;
+  MIB = BuildMI(*I->getParent(), I, I->getDebugLoc(), get(NewOpc));
+
+  for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J)
+    MIB.addOperand(I->getOperand(J));
+
+  MIB.setMemRefs(I->memoperands_begin(), I->memoperands_end());
+  return MIB;
+}

lib/Target/Mips/MipsInstrInfo.h

@@ -17,6 +17,7 @@
 #include "Mips.h"
 #include "MipsAnalyzeImmediate.h"
 #include "MipsRegisterInfo.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Target/TargetInstrInfo.h"
 
@@ -116,6 +117,11 @@ public:
                                 const TargetRegisterInfo *TRI,
                                 int64_t Offset) const = 0;
 
+  /// Create an instruction which has the same operands and memory operands
+  /// as MI but has a new opcode.
+  MachineInstrBuilder genInstrWithNewOpc(unsigned NewOpc,
+                                         MachineBasicBlock::iterator I) const;
+
 protected:
   bool isZeroImm(const MachineOperand &op) const;