Use bidirectional bundle flags to simplify important functions.

The bundle_iterator::operator++ function now doesn't need to dig out the
basic block and check against end(). It can use the isBundledWithSucc()
flag to find the last bundled instruction safely.

Similarly, MachineInstr::isBundled() no longer needs to look at
iterators etc. It only has to look at flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170473 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineBasicBlock.h

@@ -146,11 +146,11 @@ public:
     bundle_iterator(IterTy mii) : MII(mii) {}
 
     bundle_iterator(Ty &mi) : MII(mi) {
-      assert(!mi.isInsideBundle() &&
+      assert(!mi.isBundledWithPred() &&
              "It's not legal to initialize bundle_iterator with a bundled MI");
     }
     bundle_iterator(Ty *mi) : MII(mi) {
-      assert((!mi || !mi->isInsideBundle()) &&
+      assert((!mi || !mi->isBundledWithPred()) &&
              "It's not legal to initialize bundle_iterator with a bundled MI");
     }
     // Template allows conversion from const to nonconst.
@@ -174,13 +174,13 @@ public:
     // Increment and decrement operators...
     bundle_iterator &operator--() {      // predecrement - Back up
       do --MII;
-      while (MII->isInsideBundle());
+      while (MII->isBundledWithPred());
       return *this;
     }
     bundle_iterator &operator++() {      // preincrement - Advance
-      IterTy E = MII->getParent()->instr_end();
-      do ++MII;
-      while (MII != E && MII->isInsideBundle());
+      while (MII->isBundledWithSucc())
+        ++MII;
+      ++MII;
       return *this;
     }
     bundle_iterator operator--(int) {    // postdecrement operators...

include/llvm/CodeGen/MachineInstr.h

@@ -211,7 +211,9 @@ public:
 
   /// isBundled - Return true if this instruction part of a bundle. This is true
   /// if either itself or its following instruction is marked "InsideBundle".
-  bool isBundled() const;
+  bool isBundled() const {
+    return isBundledWithPred() || isBundledWithSucc();
+  }
 
   /// Return true if this instruction is part of a bundle, and it is not the
   /// first instruction in the bundle.

lib/CodeGen/MachineInstr.cpp

@@ -909,16 +909,6 @@ void MachineInstr::unbundleFromSucc() {
   Succ->clearFlag(BundledPred);
 }
 
-/// isBundled - Return true if this instruction part of a bundle. This is true
-/// if either itself or its following instruction is marked "InsideBundle".
-bool MachineInstr::isBundled() const {
-  if (isInsideBundle())
-    return true;
-  MachineBasicBlock::const_instr_iterator nextMI = this;
-  ++nextMI;
-  return nextMI != Parent->instr_end() && nextMI->isInsideBundle();
-}
-
 bool MachineInstr::isStackAligningInlineAsm() const {
   if (isInlineAsm()) {
     unsigned ExtraInfo = getOperand(InlineAsm::MIOp_ExtraInfo).getImm();