Detect and enumerate bypass loops.
Bypass loops have the current live range live through, but contain no uses or
defs. Splitting around a bypass loop can free registers for other uses inside
the loop by spilling the split range.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121871 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index f290eb6..0930b39 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -141,6 +141,15 @@
/// separate register, or NULL.
const MachineLoop *getBestSplitLoop();
+ /// isBypassLoop - Return true if curli is live through Loop and has no uses
+ /// inside the loop. Bypass loops are candidates for splitting because it can
+ /// prevent interference inside the loop.
+ bool isBypassLoop(const MachineLoop *Loop);
+
+ /// getBypassLoops - Get all the maximal bypass loops. These are the bypass
+ /// loops whose parent is not a bypass loop.
+ void getBypassLoops(LoopPtrSet&);
+
/// getMultiUseBlocks - Add basic blocks to Blocks that may benefit from
/// having curli split to a new live interval. Return true if Blocks can be
/// passed to SplitEditor::splitSingleBlocks.