Revert "Reapply 91184 with fixes and an addition to the testcase to cover the

[oota-llvm.git] / lib / CodeGen / PHIElimination.h

diff --git a/lib/CodeGen/PHIElimination.h b/lib/CodeGen/PHIElimination.h
index 3d02dfdcddba29a84419c9c00012c8e8951312aa..b0b71ce2bc5ed7a4620a06da179bbd42902f0712 100644 (file)
--- a/lib/CodeGen/PHIElimination.h
+++ b/lib/CodeGen/PHIElimination.h
@@ -89,11 +89,22 @@ namespace llvm {
     ///
     void analyzePHINodes(const MachineFunction& Fn);
 
-    // FindCopyInsertPoint - Find a safe place in MBB to insert a copy from
-    // SrcReg.  This needs to be after any def or uses of SrcReg, but before
-    // any subsequent point where control flow might jump out of the basic
-    // block.
+    /// Split critical edges where necessary for good coalescer performance.
+    bool SplitPHIEdges(MachineFunction &MF, MachineBasicBlock &MBB,
+                       LiveVariables &LV);
+
+    /// SplitCriticalEdge - Split a critical edge from A to B by
+    /// inserting a new MBB. Update branches in A and PHI instructions
+    /// in B. Return the new block.
+    MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *A,
+                                         MachineBasicBlock *B);
+
+    /// FindCopyInsertPoint - Find a safe place in MBB to insert a copy from
+    /// SrcReg when following the CFG edge to SuccMBB. This needs to be after
+    /// any def of SrcReg, but before any subsequent point where control flow
+    /// might jump out of the basic block.
     MachineBasicBlock::iterator FindCopyInsertPoint(MachineBasicBlock &MBB,
+                                                    MachineBasicBlock &SuccMBB,
                                                     unsigned SrcReg);
 
     // SkipPHIsAndLabels - Copies need to be inserted after phi nodes and