Keep track of the head and tail of the trace through each block.

This makes it possible to quickly detect blocks that are outside the
trace.

llvm-svn: 160904

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineTraceMetrics.h b/llvm/lib/CodeGen/MachineTraceMetrics.h
index 086d7eaebff..26136fa9ee9 100644
--- a/llvm/lib/CodeGen/MachineTraceMetrics.h
+++ b/llvm/lib/CodeGen/MachineTraceMetrics.h
@@ -110,6 +110,12 @@ public:
     /// Trace successor, or NULL for the last block in the trace.
     const MachineBasicBlock *Succ;
 
+    /// The block number of the head of the trace. (When hasValidDepth()).
+    unsigned Head;
+
+    /// The block number of the tail of the trace. (When hasValidHeight()).
+    unsigned Tail;
+
     /// Accumulated number of instructions in the trace above this block.
     /// Does not include instructions in this block.
     unsigned InstrDepth;