[NFC][GlobalISel]: Add a convenience method to MachineInstrBuilder to simplify getOperand(i).getReg()

https://reviews.llvm.org/D57608

It's a common pattern in GISel to have a MachineInstrBuilder from which we get various regs
(commonly MIB->getOperand(0).getReg()). This adds a helper method and the above can be
replaced with MIB.getReg(0).

llvm-svn: 353223

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/include/llvm/CodeGen/MachineInstrBuilder.h b/llvm/include/llvm/CodeGen/MachineInstrBuilder.h
index bbafeab1577..4a8cd6861a9 100644
--- a/llvm/include/llvm/CodeGen/MachineInstrBuilder.h
+++ b/llvm/include/llvm/CodeGen/MachineInstrBuilder.h
@@ -79,6 +79,11 @@ public:
   /// explicitly.
   MachineInstr *getInstr() const { return MI; }
 
+  /// Get the register for the operand index.
+  /// The operand at the index should be a register (asserted by
+  /// MachineOperand).
+  unsigned getReg(unsigned Idx) { return MI->getOperand(Idx).getReg(); }
+
   /// Add a new virtual register operand.
   const MachineInstrBuilder &addReg(unsigned RegNo, unsigned flags = 0,
                                     unsigned SubReg = 0) const {