Build the Hopfield network incrementally when splitting global live ranges.
It is common for large live ranges to have few basic blocks with register uses
and many live-through blocks without any uses. This approach grows the Hopfield
network incrementally around the use blocks, completely avoiding checking
interference for some through blocks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129188 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 201e9b1..6195ab0 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -132,12 +132,14 @@
DEBUG(dbgs() << "Analyze counted "
<< UseSlots.size() << " instrs in "
<< UseBlocks.size() << " blocks, through "
- << ThroughBlocks.size() << " blocks.\n");
+ << NumThroughBlocks << " blocks.\n");
}
/// calcLiveBlockInfo - Fill the LiveBlocks array with information about blocks
/// where CurLI is live.
bool SplitAnalysis::calcLiveBlockInfo() {
+ ThroughBlocks.resize(MF.getNumBlockIDs());
+ NumThroughBlocks = 0;
if (CurLI->empty())
return true;
@@ -193,9 +195,10 @@
BI.LiveThrough = !hasGap && BI.LiveIn && BI.LiveOut;
if (Uses)
UseBlocks.push_back(BI);
- else
- ThroughBlocks.push_back(BI.MBB->getNumber());
-
+ else {
+ ++NumThroughBlocks;
+ ThroughBlocks.set(BI.MBB->getNumber());
+ }
// FIXME: This should never happen. The live range stops or starts without a
// corresponding use. An earlier pass did something wrong.
if (!BI.LiveThrough && !Uses)