Phase 1 of refactoring the MachineRegisterInfo iterators to make them suitable

for use with C++11 range-based for-loops.

The gist of phase 1 is to remove the skipInstruction() and skipBundle()
methods from these iterators, instead splitting each iterator into a version
that walks operands, a version that walks instructions, and a version that
walks bundles.  This has the result of making some "clever" loops in lib/CodeGen
more verbose, but also makes their iterator invalidation characteristics much
more obvious to the casual reader. (Making them concise again in the future is a
good motivating case for a pre-incrementing range adapter!)

Phase 2 of this undertaking with consist of removing the getOperand() method,
and changing operator*() of the operand-walker to return a MachineOperand&.  At
that point, it should be possible to add range views for them that work as one
might expect.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203757 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 57 insertions, 34 deletions

diff --git a/lib/CodeGen/CalcSpillWeights.cpp b/lib/CodeGen/CalcSpillWeights.cpp
index d9fccd0372..4833731fc1 100644
--- a/lib/CodeGen/CalcSpillWeights.cpp
+++ b/lib/CodeGen/CalcSpillWeights.cpp
@@ -112,8 +112,10 @@ VirtRegAuxInfo::calculateSpillWeightAndHint(LiveInterval &li) {
   // Don't recompute spill weight for an unspillable register.
   bool Spillable = li.isSpillable();
 
-  for (MachineRegisterInfo::reg_iterator I = mri.reg_begin(li.reg);
-       MachineInstr *mi = I.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_iterator
+       I = mri.reg_instr_begin(li.reg), E = mri.reg_instr_end();
+       I != E; ) {
+    MachineInstr *mi = &*(I++);
     if (mi->isIdentityCopy() || mi->isImplicitDef() || mi->isDebugValue())
       continue;
     if (!visited.insert(mi))
diff --git a/lib/CodeGen/InlineSpiller.cpp b/lib/CodeGen/InlineSpiller.cpp
index bf716d877e..64211c8d31 100644
--- a/lib/CodeGen/InlineSpiller.cpp
+++ b/lib/CodeGen/InlineSpiller.cpp
@@ -238,9 +238,10 @@ bool InlineSpiller::isSnippet(const LiveInterval &SnipLI) {
   MachineInstr *UseMI = 0;
 
   // Check that all uses satisfy our criteria.
-  for (MachineRegisterInfo::reg_nodbg_iterator
-         RI = MRI.reg_nodbg_begin(SnipLI.reg);
-       MachineInstr *MI = RI.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_nodbg_iterator
+       RI = MRI.reg_instr_nodbg_begin(SnipLI.reg),
+       E = MRI.reg_instr_nodbg_end(); RI != E; ) {
+    MachineInstr *MI = &*(RI++);
 
     // Allow copies to/from Reg.
     if (isFullCopyOf(MI, Reg))
@@ -277,8 +278,9 @@ void InlineSpiller::collectRegsToSpill() {
   if (Original == Reg)
     return;
 
-  for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(Reg);
-       MachineInstr *MI = RI.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_iterator
+       RI = MRI.reg_instr_begin(Reg), E = MRI.reg_instr_end(); RI != E; ) {
+    MachineInstr *MI = &*(RI++);
     unsigned SnipReg = isFullCopyOf(MI, Reg);
     if (!isSibling(SnipReg))
       continue;
@@ -759,8 +761,10 @@ void InlineSpiller::eliminateRedundantSpills(LiveInterval &SLI, VNInfo *VNI) {
     DEBUG(dbgs() << "Merged to stack int: " << *StackInt << '\n');
 
     // Find all spills and copies of VNI.
-    for (MachineRegisterInfo::use_nodbg_iterator UI = MRI.use_nodbg_begin(Reg);
-         MachineInstr *MI = UI.skipInstruction();) {
+    for (MachineRegisterInfo::use_instr_nodbg_iterator
+         UI = MRI.use_instr_nodbg_begin(Reg), E = MRI.use_instr_nodbg_end();
+         UI != E; ) {
+      MachineInstr *MI = &*(UI++);
       if (!MI->isCopy() && !MI->mayStore())
         continue;
       SlotIndex Idx = LIS.getInstructionIndex(MI);
@@ -920,10 +924,12 @@ void InlineSpiller::reMaterializeAll() {
   for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i) {
     unsigned Reg = RegsToSpill[i];
     LiveInterval &LI = LIS.getInterval(Reg);
-    for (MachineRegisterInfo::use_nodbg_iterator
-         RI = MRI.use_nodbg_begin(Reg);
-         MachineInstr *MI = RI.skipBundle();)
+    for (MachineRegisterInfo::use_bundle_nodbg_iterator
+         RI = MRI.use_bundle_nodbg_begin(Reg), E = MRI.use_bundle_nodbg_end();
+         RI != E; ) {
+      MachineInstr *MI = &*(RI++);
       anyRemat |= reMaterializeFor(LI, MI);
+    }
   }
   if (!anyRemat)
     return;
@@ -1187,8 +1193,10 @@ void InlineSpiller::spillAroundUses(unsigned Reg) {
   LiveInterval &OldLI = LIS.getInterval(Reg);
 
   // Iterate over instructions using Reg.
-  for (MachineRegisterInfo::reg_iterator RegI = MRI.reg_begin(Reg);
-       MachineInstr *MI = RegI.skipBundle();) {
+  for (MachineRegisterInfo::reg_bundle_iterator
+       RegI = MRI.reg_bundle_begin(Reg), E = MRI.reg_bundle_end();
+       RegI != E; ) {
+    MachineInstr *MI = &*(RegI++);
 
     // Debug values are not allowed to affect codegen.
     if (MI->isDebugValue()) {
@@ -1313,8 +1321,10 @@ void InlineSpiller::spillAll() {
 
   // Finally delete the SnippetCopies.
   for (unsigned i = 0, e = RegsToSpill.size(); i != e; ++i) {
-    for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(RegsToSpill[i]);
-         MachineInstr *MI = RI.skipInstruction();) {
+    for (MachineRegisterInfo::reg_instr_iterator
+         RI = MRI.reg_instr_begin(RegsToSpill[i]), E = MRI.reg_instr_end();
+         RI != E; ) {
+      MachineInstr *MI = &*(RI++);
       assert(SnippetCopies.count(MI) && "Remaining use wasn't a snippet copy");
       // FIXME: Do this with a LiveRangeEdit callback.
       LIS.RemoveMachineInstrFromMaps(MI);
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index a5cadf4916..fdc673f71e 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -326,8 +326,10 @@ bool LiveIntervals::shrinkToUses(LiveInterval *li,
   SmallPtrSet<MachineBasicBlock*, 16> LiveOut;
 
   // Visit all instructions reading li->reg.
-  for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(li->reg);
-       MachineInstr *UseMI = I.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_iterator
+       I = MRI->reg_instr_begin(li->reg), E = MRI->reg_instr_end();
+       I != E; ) {
+    MachineInstr *UseMI = &*(I++);
     if (UseMI->isDebugValue() || !UseMI->readsVirtualRegister(li->reg))
       continue;
     SlotIndex Idx = getInstructionIndex(UseMI).getRegSlot();
@@ -980,10 +982,10 @@ private:
 
     if (TargetRegisterInfo::isVirtualRegister(Reg)) {
       SlotIndex LastUse = NewIdx;
-      for (MachineRegisterInfo::use_nodbg_iterator
-             UI = MRI.use_nodbg_begin(Reg),
-             UE = MRI.use_nodbg_end();
-           UI != UE; UI.skipInstruction()) {
+      for (MachineRegisterInfo::use_instr_nodbg_iterator
+             UI = MRI.use_instr_nodbg_begin(Reg),
+             UE = MRI.use_instr_nodbg_end();
+           UI != UE; ++UI) {
         const MachineInstr* MI = &*UI;
         SlotIndex InstSlot = LIS.getSlotIndexes()->getInstructionIndex(MI);
         if (InstSlot > LastUse && InstSlot < OldIdx)
diff --git a/lib/CodeGen/RegAllocBase.cpp b/lib/CodeGen/RegAllocBase.cpp
index 48aadc2a5f..33584f8680 100644
--- a/lib/CodeGen/RegAllocBase.cpp
+++ b/lib/CodeGen/RegAllocBase.cpp
@@ -110,11 +110,16 @@ void RegAllocBase::allocatePhysRegs() {
     if (AvailablePhysReg == ~0u) {
       // selectOrSplit failed to find a register!
       // Probably caused by an inline asm.
-      MachineInstr *MI;
-      for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(VirtReg->reg);
-           (MI = I.skipInstruction());)
-        if (MI->isInlineAsm())
+      MachineInstr *MI = 0;
+      for (MachineRegisterInfo::reg_instr_iterator
+           I = MRI->reg_instr_begin(VirtReg->reg), E = MRI->reg_instr_end();
+           I != E; ) {
+        MachineInstr *TmpMI = &*(I++);
+        if (TmpMI->isInlineAsm()) {
+          MI = TmpMI;
           break;
+        }
+      }
       if (MI)
         MI->emitError("inline assembly requires more registers than available");
       else
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index 64e6da51e4..13ea1a58e0 100644
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -939,8 +939,11 @@ void RegisterCoalescer::updateRegDefsUses(unsigned SrcReg,
   LiveInterval *DstInt = DstIsPhys ? 0 : &LIS->getInterval(DstReg);
 
   SmallPtrSet<MachineInstr*, 8> Visited;
-  for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(SrcReg);
-       MachineInstr *UseMI = I.skipInstruction();) {
+  for (MachineRegisterInfo::reg_instr_iterator
+       I = MRI->reg_instr_begin(SrcReg), E = MRI->reg_instr_end();
+       I != E; ) {
+    MachineInstr *UseMI = &*(I++);
+
     // Each instruction can only be rewritten once because sub-register
     // composition is not always idempotent. When SrcReg != DstReg, rewriting
     // the UseMI operands removes them from the SrcReg use-def chain, but when
diff --git a/lib/CodeGen/RegisterPressure.cpp b/lib/CodeGen/RegisterPressure.cpp
index cfeafbf403..97817daac5 100644
--- a/lib/CodeGen/RegisterPressure.cpp
+++ b/lib/CodeGen/RegisterPressure.cpp
@@ -882,9 +882,9 @@ static bool findUseBetween(unsigned Reg,
                            SlotIndex PriorUseIdx, SlotIndex NextUseIdx,
                            const MachineRegisterInfo *MRI,
                            const LiveIntervals *LIS) {
-  for (MachineRegisterInfo::use_nodbg_iterator
-         UI = MRI->use_nodbg_begin(Reg), UE = MRI->use_nodbg_end();
-         UI != UE; UI.skipInstruction()) {
+  for (MachineRegisterInfo::use_instr_nodbg_iterator
+       UI = MRI->use_instr_nodbg_begin(Reg),
+       UE = MRI->use_instr_nodbg_end(); UI != UE; ++UI) {
       const MachineInstr* MI = &*UI;
       if (MI->isDebugValue())
         continue;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index cda0b57a15..5d0e2b937d 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -483,9 +483,10 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) {
       // that COPY instructions also need DBG_VALUE, if it is the only
       // user of LDI->second.
       MachineInstr *CopyUseMI = NULL;
-      for (MachineRegisterInfo::use_iterator
-             UI = RegInfo->use_begin(LDI->second);
-           MachineInstr *UseMI = UI.skipInstruction();) {
+      for (MachineRegisterInfo::use_instr_iterator
+           UI = RegInfo->use_instr_begin(LDI->second),
+           E = RegInfo->use_instr_end(); UI != E; ) {
+        MachineInstr *UseMI = &*(UI++);
         if (UseMI->isDebugValue()) continue;
         if (UseMI->isCopy() && !CopyUseMI && UseMI->getParent() == EntryMBB) {
           CopyUseMI = UseMI; continue;