Use basic block numbers as indexes when mapping slot index ranges.

This is more compact and faster than using DenseMap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128763 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/SlotIndexes.h

@@ -337,15 +337,12 @@ namespace llvm {
     typedef DenseMap<const MachineInstr*, SlotIndex> Mi2IndexMap;
     Mi2IndexMap mi2iMap;
 
-    /// MBB2IdxMap - The indexes of the first and last instructions in the
-    /// specified basic block.
-    typedef DenseMap<const MachineBasicBlock*,
-                     std::pair<SlotIndex, SlotIndex> > MBB2IdxMap;
-    MBB2IdxMap mbb2IdxMap;
+    /// MBBRanges - Map MBB number to (start, stop) indexes.
+    SmallVector<std::pair<SlotIndex, SlotIndex>, 8> MBBRanges;
 
     /// Idx2MBBMap - Sorted list of pairs of index of first instruction
     /// and MBB id.
-    std::vector<IdxMBBPair> idx2MBBMap;
+    SmallVector<IdxMBBPair, 8> idx2MBBMap;
 
     // IndexListEntry allocator.
     BumpPtrAllocator ileAllocator;
@@ -509,12 +506,16 @@ namespace llvm {
       return nextNonNull;
     }
 
+    /// Return the (start,end) range of the given basic block number.
+    const std::pair<SlotIndex, SlotIndex> &
+    getMBBRange(unsigned Num) const {
+      return MBBRanges[Num];
+    }
+
     /// Return the (start,end) range of the given basic block.
     const std::pair<SlotIndex, SlotIndex> &
-    getMBBRange(const MachineBasicBlock *mbb) const {
-      MBB2IdxMap::const_iterator itr = mbb2IdxMap.find(mbb);
-      assert(itr != mbb2IdxMap.end() && "MBB not found in maps.");
-      return itr->second;
+    getMBBRange(const MachineBasicBlock *MBB) const {
+      return getMBBRange(MBB->getNumber());
     }
 
     /// Returns the first index in the given basic block.
@@ -529,10 +530,10 @@ namespace llvm {
 
     /// Returns the basic block which the given index falls in.
     MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
-      std::vector<IdxMBBPair>::const_iterator I =
+      SmallVectorImpl<IdxMBBPair>::const_iterator I =
         std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), index);
       // Take the pair containing the index
-      std::vector<IdxMBBPair>::const_iterator J =
+      SmallVectorImpl<IdxMBBPair>::const_iterator J =
         ((I != idx2MBBMap.end() && I->first > index) ||
          (I == idx2MBBMap.end() && idx2MBBMap.size()>0)) ? (I-1): I;
 
@@ -544,7 +545,7 @@ namespace llvm {
 
     bool findLiveInMBBs(SlotIndex start, SlotIndex end,
                         SmallVectorImpl<MachineBasicBlock*> &mbbs) const {
-      std::vector<IdxMBBPair>::const_iterator itr =
+      SmallVectorImpl<IdxMBBPair>::const_iterator itr =
         std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
       bool resVal = false;
 
@@ -564,7 +565,7 @@ namespace llvm {
 
       assert(start < end && "Backwards ranges not allowed.");
 
-      std::vector<IdxMBBPair>::const_iterator itr =
+      SmallVectorImpl<IdxMBBPair>::const_iterator itr =
         std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
 
       if (itr == idx2MBBMap.end()) {
@@ -596,11 +597,6 @@ namespace llvm {
 
       assert(mbb != 0 && "Instr must be added to function.");
 
-      MBB2IdxMap::iterator mbbRangeItr = mbb2IdxMap.find(mbb);
-
-      assert(mbbRangeItr != mbb2IdxMap.end() &&
-             "Instruction's parent MBB has not been added to SlotIndexes.");
-
       MachineBasicBlock::iterator miItr(mi);
       IndexListEntry *newEntry;
       // Get previous index, considering that not all instructions are indexed.
@@ -608,7 +604,7 @@ namespace llvm {
       for (;;) {
         // If mi is at the mbb beginning, get the prev index from the mbb.
         if (miItr == mbb->begin()) {
-          prevEntry = &mbbRangeItr->second.first.entry();
+          prevEntry = &getMBBStartIdx(mbb).entry();
           break;
         }
         // Otherwise rewind until we find a mapped instruction.
@@ -689,21 +685,14 @@ namespace llvm {
       SlotIndex startIdx(startEntry, SlotIndex::LOAD);
       SlotIndex endIdx(nextEntry, SlotIndex::LOAD);
 
-      mbb2IdxMap.insert(
-        std::make_pair(mbb, std::make_pair(startIdx, endIdx)));
+      assert(unsigned(mbb->getNumber()) == MBBRanges.size() &&
+             "Blocks must be added in order");
+      MBBRanges.push_back(std::make_pair(startIdx, endIdx));
 
       idx2MBBMap.push_back(IdxMBBPair(startIdx, mbb));
 
-      if (MachineFunction::iterator(mbb) != mbb->getParent()->begin()) {
-        // Have to update the end index of the previous block.
-        MachineBasicBlock *priorMBB =
-          llvm::prior(MachineFunction::iterator(mbb));
-        mbb2IdxMap[priorMBB].second = startIdx;
-      }
-
       renumberIndexes();
       std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
-
     }
 
   };

lib/CodeGen/SlotIndexes.cpp

@@ -32,7 +32,7 @@ void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const {
 
 void SlotIndexes::releaseMemory() {
   mi2iMap.clear();
-  mbb2IdxMap.clear();
+  MBBRanges.clear();
   idx2MBBMap.clear();
   clearList();
 }
@@ -58,13 +58,15 @@ bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
          "Index list non-empty at initial numbering?");
   assert(idx2MBBMap.empty() &&
          "Index -> MBB mapping non-empty at initial numbering?");
-  assert(mbb2IdxMap.empty() &&
+  assert(MBBRanges.empty() &&
          "MBB -> Index mapping non-empty at initial numbering?");
   assert(mi2iMap.empty() &&
          "MachineInstr -> Index mapping non-empty at initial numbering?");
 
   functionSize = 0;
   unsigned index = 0;
+  MBBRanges.resize(mf->getNumBlockIDs());
+  idx2MBBMap.reserve(mf->size());
 
   push_back(createEntry(0, index));
 
@@ -94,10 +96,8 @@ bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
     // We insert one blank instructions between basic blocks.
     push_back(createEntry(0, index += SlotIndex::InstrDist));
 
-    SlotIndex blockEndIndex(back(), SlotIndex::LOAD);
-    mbb2IdxMap.insert(
-      std::make_pair(mbb, std::make_pair(blockStartIndex, blockEndIndex)));
-
+    MBBRanges[mbb->getNumber()].first = blockStartIndex;
+    MBBRanges[mbb->getNumber()].second = SlotIndex(back(), SlotIndex::LOAD);
     idx2MBBMap.push_back(IdxMBBPair(blockStartIndex, mbb));
   }
 
@@ -158,11 +158,9 @@ void SlotIndexes::dump() const {
     }
   }
 
-  for (MBB2IdxMap::const_iterator itr = mbb2IdxMap.begin();
-       itr != mbb2IdxMap.end(); ++itr) {
-    dbgs() << "MBB " << itr->first->getNumber() << " (" << itr->first << ") - ["
-           << itr->second.first << ", " << itr->second.second << "]\n";
-  }
+  for (unsigned i = 0, e = MBBRanges.size(); i != e; ++i)
+    dbgs() << "BB#" << i << "\t[" << MBBRanges[i].first << ';'
+           << MBBRanges[i].second << ")\n";
 }
 
 // Print a SlotIndex to a raw_ostream.