Add SplitAnalysis::getNumLiveBlocks().

It is important that this function returns the same number of live blocks as
countLiveBlocks(CurLI) because live range splitting uses the number of live
blocks to ensure it is making progress.

This is in preparation of supporting duplicate UseBlock entries for basic blocks
that have a virtual register live-in and live-out, but not live-though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132244 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 12 insertions, 5 deletions

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index af77b476c8..2d03760fc7 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -976,7 +976,7 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg,
   DebugVars->splitRegister(VirtReg.reg, LREdit.regs());
 
   LRStage.resize(MRI->getNumVirtRegs());
-  unsigned OrigBlocks = SA->getNumThroughBlocks() + SA->getUseBlocks().size();
+  unsigned OrigBlocks = SA->getNumLiveBlocks();
 
   // Sort out the new intervals created by splitting. We get four kinds:
   // - Remainder intervals should not be split again.
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 55ae97c792..53141b54c9 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -224,6 +224,8 @@ bool SplitAnalysis::calcLiveBlockInfo() {
     else
       MFI = LIS.getMBBFromIndex(LVI->start);
   }
+
+  assert(getNumLiveBlocks() == countLiveBlocks(CurLI) && "Bad block count");
   return true;
 }
 
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index 6305d0cc23..dc27486e73 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -147,7 +147,7 @@ public:
 
   /// getUseBlocks - Return an array of BlockInfo objects for the basic blocks
   /// where CurLI has uses.
-  ArrayRef<BlockInfo> getUseBlocks() { return UseBlocks; }
+  ArrayRef<BlockInfo> getUseBlocks() const { return UseBlocks; }
 
   /// getNumThroughBlocks - Return the number of through blocks.
   unsigned getNumThroughBlocks() const { return NumThroughBlocks; }
@@ -158,9 +158,14 @@ public:
   /// getThroughBlocks - Return the set of through blocks.
   const BitVector &getThroughBlocks() const { return ThroughBlocks; }
 
-  /// countLiveBlocks - Return the number of blocks where li is live.
-  /// This is guaranteed to return the same number as getNumThroughBlocks() +
-  /// getUseBlocks().size() after calling analyze(li).
+  /// getNumLiveBlocks - Return the number of blocks where CurLI is live.
+  unsigned getNumLiveBlocks() const {
+    return getUseBlocks().size() + getNumThroughBlocks();
+  }
+
+  /// countLiveBlocks - Return the number of blocks where li is live. This is
+  /// guaranteed to return the same number as getNumLiveBlocks() after calling
+  /// analyze(li).
   unsigned countLiveBlocks(const LiveInterval *li) const;
 
   typedef SmallPtrSet<const MachineBasicBlock*, 16> BlockPtrSet;