CodeGen: Use mop_iterator instead of MIOperands/ConstMIOperands

MIOperands/ConstMIOperands are classes iterating over the MachineOperand
of a MachineInstr, however MachineInstr::mop_iterator does the same
thing.

I assume these two iterators exist to have a uniform interface to
iterate over the operands of a machine instruction bundle and a single
machine instruction. However in practice I find it more confusing to have 2
different iterator classes, so this patch transforms (nearly all) the
code to use mop_iterators.

The only exception being MIOperands::anlayzePhysReg() and
MIOperands::analyzeVirtReg() still needing an equivalent, I leave that
as an exercise for the next patch.

Differential Revision: http://reviews.llvm.org/D9932

This version is slightly modified from the proposed revision in that it
introduces MachineInstr::getOperandNo to avoid the extra counting
variable in the few loops that previously used MIOperands::getOperandNo.

llvm-svn: 238539

1 files changed, 2 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 205032f9297..e67102865bf 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -1092,9 +1092,8 @@ const TargetRegisterClass *MachineInstr::getRegClassConstraintEffectForVReg(
           OpndIt.getOperandNo(), Reg, CurRC, TII, TRI);
   else
     // Otherwise, just check the current operands.
-    for (ConstMIOperands OpndIt(this); OpndIt.isValid() && CurRC; ++OpndIt)
-      CurRC = getRegClassConstraintEffectForVRegImpl(OpndIt.getOperandNo(), Reg,
-                                                     CurRC, TII, TRI);
+    for (unsigned i = 0, e = NumOperands; i < e && CurRC; ++i)
+      CurRC = getRegClassConstraintEffectForVRegImpl(i, Reg, CurRC, TII, TRI);
   return CurRC;
 }