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

4 files changed, 19 insertions, 17 deletions

diff --git a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
index 5b62a21706c..019261edb5b 100644
--- a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -762,10 +762,10 @@ void ARMLoadStoreOpt::MergeOpsUpdate(MachineBasicBlock &MBB,
     Regs.push_back(std::make_pair(Reg, isKill));
 
     // Collect any implicit defs of super-registers. They must be preserved.
-    for (MIOperands MO(memOps[i].MBBI); MO.isValid(); ++MO) {
-      if (!MO->isReg() || !MO->isDef() || !MO->isImplicit() || MO->isDead())
+    for (const MachineOperand &MO : memOps[i].MBBI->operands()) {
+      if (!MO.isReg() || !MO.isDef() || !MO.isImplicit() || MO.isDead())
         continue;
-      unsigned DefReg = MO->getReg();
+      unsigned DefReg = MO.getReg();
       if (std::find(ImpDefs.begin(), ImpDefs.end(), DefReg) == ImpDefs.end())
         ImpDefs.push_back(DefReg);
 
diff --git a/llvm/lib/Target/ARM/Thumb2ITBlockPass.cpp b/llvm/lib/Target/ARM/Thumb2ITBlockPass.cpp
index b62ae2e3429..68736bc1dec 100644
--- a/llvm/lib/Target/ARM/Thumb2ITBlockPass.cpp
+++ b/llvm/lib/Target/ARM/Thumb2ITBlockPass.cpp
@@ -94,12 +94,12 @@ static void TrackDefUses(MachineInstr *MI,
 /// conservatively remove more kill flags than are necessary, but removing them
 /// is safer than incorrect kill flags remaining on instructions.
 static void ClearKillFlags(MachineInstr *MI, SmallSet<unsigned, 4> &Uses) {
-  for (MIOperands MO(MI); MO.isValid(); ++MO) {
-    if (!MO->isReg() || MO->isDef() || !MO->isKill())
+  for (MachineOperand &MO : MI->operands()) {
+    if (!MO.isReg() || MO.isDef() || !MO.isKill())
       continue;
-    if (!Uses.count(MO->getReg()))
+    if (!Uses.count(MO.getReg()))
       continue;
-    MO->setIsKill(false);
+    MO.setIsKill(false);
   }
 }
 
diff --git a/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp b/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
index 0885a794a7b..868f87e1841 100644
--- a/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
@@ -201,17 +201,17 @@ namespace {
           break;
       }
       // Check individual operands.
-      for (ConstMIOperands Mo(MI); Mo.isValid(); ++Mo) {
+      for (const MachineOperand &MO : MI->operands()) {
         // While the presence of a frame index does not prove that a stack
         // frame will be required, all frame indexes should be within alloc-
         // frame/deallocframe. Otherwise, the code that translates a frame
         // index into an offset would have to be aware of the placement of
         // the frame creation/destruction instructions.
-        if (Mo->isFI())
+        if (MO.isFI())
           return true;
-        if (!Mo->isReg())
+        if (!MO.isReg())
           continue;
-        unsigned R = Mo->getReg();
+        unsigned R = MO.getReg();
         // Virtual registers will need scavenging, which then may require
         // a stack slot.
         if (TargetRegisterInfo::isVirtualRegister(R))
diff --git a/llvm/lib/Target/X86/X86FastISel.cpp b/llvm/lib/Target/X86/X86FastISel.cpp
index 9af0aebea23..d1d053ae36b 100644
--- a/llvm/lib/Target/X86/X86FastISel.cpp
+++ b/llvm/lib/Target/X86/X86FastISel.cpp
@@ -3541,16 +3541,18 @@ bool X86FastISel::tryToFoldLoadIntoMI(MachineInstr *MI, unsigned OpNo,
   // to just look at OpNo + the offset to the index reg.  We actually need to
   // scan the instruction to find the index reg and see if its the correct reg
   // class.
-  for (MIOperands MO(Result); MO.isValid(); ++MO) {
-    if (!MO->isReg() || MO->isDef() || MO->getReg() != AM.IndexReg)
+  unsigned OperandNo = 0;
+  for (MachineInstr::mop_iterator I = Result->operands_begin(),
+       E = Result->operands_end(); I != E; ++I, ++OperandNo) {
+    MachineOperand &MO = *I;
+    if (!MO.isReg() || MO.isDef() || MO.getReg() != AM.IndexReg)
       continue;
     // Found the index reg, now try to rewrite it.
-    unsigned OpNo = MO.getOperandNo();
     unsigned IndexReg = constrainOperandRegClass(Result->getDesc(),
-                                                 MO->getReg(), OpNo);
-    if (IndexReg == MO->getReg())
+                                                 MO.getReg(), OperandNo);
+    if (IndexReg == MO.getReg())
       continue;
-    MO->setReg(IndexReg);
+    MO.setReg(IndexReg);
   }
 
   Result->addMemOperand(*FuncInfo.MF, createMachineMemOperandFor(LI));