Create new intervals for isolated blocks during region splitting.

This merges the behavior of splitSingleBlocks into splitAroundRegion, so the
RS_Region and RS_Block register stages can be coalesced. That means the leftover
intervals after region splitting go directly to spilling instead of a second
pass of per-block splitting.

llvm-svn: 129379

1 files changed, 18 insertions, 16 deletions

diff --git a/llvm/lib/CodeGen/SplitKit.cpp b/llvm/lib/CodeGen/SplitKit.cpp
index f85d5d3..73788f6 100644
--- a/llvm/lib/CodeGen/SplitKit.cpp
+++ b/llvm/lib/CodeGen/SplitKit.cpp
@@ -935,6 +935,22 @@ bool SplitAnalysis::getMultiUseBlocks(BlockPtrSet &Blocks) {
   return !Blocks.empty();
 }
 
+void SplitEditor::splitSingleBlock(const SplitAnalysis::BlockInfo &BI) {
+  openIntv();
+  SlotIndex LastSplitPoint = SA.getLastSplitPoint(BI.MBB->getNumber());
+  SlotIndex SegStart = enterIntvBefore(std::min(BI.FirstUse,
+    LastSplitPoint));
+  if (!BI.LiveOut || BI.LastUse < LastSplitPoint) {
+    useIntv(SegStart, leaveIntvAfter(BI.LastUse));
+  } else {
+      // The last use is after the last valid split point.
+    SlotIndex SegStop = leaveIntvBefore(LastSplitPoint);
+    useIntv(SegStart, SegStop);
+    overlapIntv(SegStop, BI.LastUse);
+  }
+  closeIntv();
+}
+
 /// splitSingleBlocks - Split CurLI into a separate live interval inside each
 /// basic block in Blocks.
 void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
@@ -942,22 +958,8 @@ void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
   ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA.getUseBlocks();
   for (unsigned i = 0; i != UseBlocks.size(); ++i) {
     const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
-    if (!Blocks.count(BI.MBB))
-      continue;
-
-    openIntv();
-    SlotIndex LastSplitPoint = SA.getLastSplitPoint(BI.MBB->getNumber());
-    SlotIndex SegStart = enterIntvBefore(std::min(BI.FirstUse,
-                                                  LastSplitPoint));
-    if (!BI.LiveOut || BI.LastUse < LastSplitPoint) {
-      useIntv(SegStart, leaveIntvAfter(BI.LastUse));
-    } else {
-      // The last use is after the last valid split point.
-      SlotIndex SegStop = leaveIntvBefore(LastSplitPoint);
-      useIntv(SegStart, SegStop);
-      overlapIntv(SegStop, BI.LastUse);
-    }
-    closeIntv();
+    if (Blocks.count(BI.MBB))
+      splitSingleBlock(BI);
   }
   finish();
 }