Analyze blocks with uses separately from live-through blocks without uses.

About 90% of the relevant blocks are live-through without uses, and the only
information required about them is their number. This saves memory and enables
later optimizations that need to look at only the use-blocks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128985 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 5 deletions

diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index 793989f7e3..20ac8a1fdc 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/IndexedMap.h"
@@ -69,16 +70,11 @@ public:
     SlotIndex LastUse;    ///< Last instr using current reg.
     SlotIndex Kill;       ///< Interval end point inside block.
     SlotIndex Def;        ///< Interval start point inside block.
-    bool Uses;            ///< Current reg has uses or defs in block.
     bool LiveThrough;     ///< Live in whole block (Templ 5. or 6. above).
     bool LiveIn;          ///< Current reg is live in.
     bool LiveOut;         ///< Current reg is live out.
   };
 
-  /// Basic blocks where var is live. This array is parallel to
-  /// SpillConstraints.
-  SmallVector<BlockInfo, 8> LiveBlocks;
-
 private:
   // Current live interval.
   const LiveInterval *CurLI;
@@ -89,6 +85,12 @@ private:
   /// successor.
   SmallVector<std::pair<SlotIndex, SlotIndex>, 8> LastSplitPoint;
 
+  /// UseBlocks - Blocks where CurLI has uses.
+  SmallVector<BlockInfo, 8> UseBlocks;
+
+  /// ThroughBlocks - Block numbers where CurLI is live through without uses.
+  SmallVector<unsigned, 8> ThroughBlocks;
+
   SlotIndex computeLastSplitPoint(unsigned Num);
 
   // Sumarize statistics by counting instructions using CurLI.
@@ -129,6 +131,14 @@ public:
   /// splitting.
   bool isOriginalEndpoint(SlotIndex Idx) const;
 
+  /// getUseBlocks - Return an array of BlockInfo objects for the basic blocks
+  /// where CurLI has uses.
+  ArrayRef<BlockInfo> getUseBlocks() { return UseBlocks; }
+
+  /// getThroughBlocks - Return an array of block numbers where CurLI is live
+  /// through without uses.
+  ArrayRef<unsigned> getThroughBlocks() { return ThroughBlocks; }
+
   typedef SmallPtrSet<const MachineBasicBlock*, 16> BlockPtrSet;
 
   /// getMultiUseBlocks - Add basic blocks to Blocks that may benefit from