Remove use of reverse iterators in repairIntervalsInRange(). While they were

arguably better than forward iterators for this use case, they are confusing and
there are some implementation problems with reverse iterators and MI bundles.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175393 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 46dfd92801ae588093c025337e54f4b7a3583c5c..c0de49e52ab78638cfa75135ce56d4afd39768ec 100644 (file)
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -282,9 +282,9 @@ namespace llvm {
                               bool UpdateFlags = false);
 
     /// repairIntervalsInRange - Update live intervals for instructions in a
-    /// small range of reverse iterators. It is intended for use after target
-    /// hooks that may insert or remove instructions, and is only efficient for
-    /// a small number of instructions.
+    /// range of iterators. It is intended for use after target hooks that may
+    /// insert or remove instructions, and is only efficient for a small number
+    /// of instructions.
     ///
     /// OrigRegs is a vector of registers that were originally used by the
     /// instructions in the range between the two iterators.
@@ -292,8 +292,8 @@ namespace llvm {
     /// Currently, the only only changes that are supported are simple removal
     /// and addition of uses.
     void repairIntervalsInRange(MachineBasicBlock *MBB,
-                                MachineBasicBlock::reverse_iterator RBegin,
-                                MachineBasicBlock::reverse_iterator REnd,
+                                MachineBasicBlock::iterator Begin,
+                                MachineBasicBlock::iterator End,
                                 ArrayRef<unsigned> OrigRegs);
 
     // Register mask functions.

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index e09ac4bfbd8295a9fad5390d308a17463bbd13b6..0978d7342ecb7dc0afab6fcd6b8d05d72adda787 100644 (file)
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -1035,19 +1035,24 @@ void LiveIntervals::handleMoveIntoBundle(MachineInstr* MI,
 
 void
 LiveIntervals::repairIntervalsInRange(MachineBasicBlock *MBB,
-                                     MachineBasicBlock::reverse_iterator RBegin,
-                                     MachineBasicBlock::reverse_iterator REnd,
+                                      MachineBasicBlock::iterator Begin,
+                                      MachineBasicBlock::iterator End,
                                       ArrayRef<unsigned> OrigRegs) {
+  SlotIndex startIdx;
+  if (Begin == MBB->begin())
+    startIdx = getMBBStartIdx(MBB);
+  else
+    startIdx = getInstructionIndex(prior(Begin)).getRegSlot();
+
   for (unsigned i = 0, e = OrigRegs.size(); i != e; ++i) {
     unsigned Reg = OrigRegs[i];
     if (!TargetRegisterInfo::isVirtualRegister(Reg))
       continue;
 
     LiveInterval &LI = getInterval(Reg);
-    SlotIndex startIdx = (REnd == MBB->rend()) ? getMBBStartIdx(MBB)
-                                               : getInstructionIndex(&*REnd);
-    for (MachineBasicBlock::reverse_iterator I = RBegin; I != REnd; ++I) {
-      MachineInstr *MI = &*I;
+    for (MachineBasicBlock::iterator I = End; I != Begin;) {
+      --I;
+      MachineInstr *MI = I;
       SlotIndex instrIdx = getInstructionIndex(MI);
 
       for (MachineInstr::mop_iterator OI = MI->operands_begin(),
@@ -1059,7 +1064,7 @@ LiveIntervals::repairIntervalsInRange(MachineBasicBlock *MBB,
         assert(MO.isUse() && "Register defs are not yet supported.");
 
         if (!LI.liveAt(instrIdx)) {
-          LiveRange *LR = LI.getLiveRangeContaining(startIdx.getRegSlot());
+          LiveRange *LR = LI.getLiveRangeContaining(startIdx);
           assert(LR && "Used registers must be live-in.");
           LR->end = instrIdx.getRegSlot();
           break;

diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp
index f22a70716ebf6ccb4637052a1cec35117d758827..898e165feeab6b163bc56b6b9f00f5a02796d50a 100644 (file)
--- a/lib/CodeGen/MachineBasicBlock.cpp
+++ b/lib/CodeGen/MachineBasicBlock.cpp
@@ -851,15 +851,7 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
 
     // Update all intervals for registers whose uses may have been modified by
     // updateTerminator().
-    iterator FirstTerminator = getFirstTerminator();
-    reverse_iterator PreTerminators;
-    if (FirstTerminator == begin())
-      PreTerminators = rend();
-    else if (FirstTerminator == end())
-      PreTerminators = rbegin();
-    else
-      PreTerminators = reverse_iterator(FirstTerminator);
-    LIS->repairIntervalsInRange(this, rbegin(), PreTerminators, UsedRegs);
+    LIS->repairIntervalsInRange(this, getFirstTerminator(), end(), UsedRegs);
   }
 
   if (MachineDominatorTree *MDT =