Add support for updating the LiveIntervals of registers used by 'exotic'

terminators that actually have register uses when splitting critical edges.

This commit also introduces a method repairIntervalsInRange() on LiveIntervals,
which allows for repairing LiveIntervals in a small range after an arbitrary
target hook modifies, inserts, and removes instructions. It's pretty limited
right now, but I hope to extend it to support all of the things that are done
by the convertToThreeAddress() target hooks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175382 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index b6cc111b73..f422a6f3e9 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -281,6 +281,21 @@ namespace llvm {
     void handleMoveIntoBundle(MachineInstr* MI, MachineInstr* BundleStart,
                               bool UpdateFlags = false);
 
+    /// repairIntervalsInRange - Update live intervals for instructions in a
+    /// small range of reverse iterators. It is intended for use after target
+    /// hooks that may insert or remove instructions, and is only efficient for
+    /// a small number of instructions.
+    ///
+    /// OrigRegs is a vector of registers that were originally used by the
+    /// instructions in the range between the two iterators.
+    ///
+    /// Currently, the only only changes that are supported are simple removal
+    /// and addition of uses.
+    void repairIntervalsInRange(MachineBasicBlock *MBB,
+                                MachineBasicBlock::reverse_iterator RBegin,
+                                MachineBasicBlock::reverse_iterator REnd,
+                                SmallVectorImpl<unsigned> &OrigRegs);
+
     // Register mask functions.
     //
     // Machine instructions may use a register mask operand to indicate that a