Add more trace query functions.

Trace::getResourceLength() computes the number of cycles required to
execute the trace when ignoring data dependencies. The number can be
compared to the critical path to estimate the trace ILP.

Trace::getPHIDepth() computes the data dependency depth of a PHI in a
trace successor that isn't necessarily part of the trace.

llvm-svn: 161711

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineTraceMetrics.h b/llvm/lib/CodeGen/MachineTraceMetrics.h
index 4f39aca490c..c5b86f31dba 100644
--- a/llvm/lib/CodeGen/MachineTraceMetrics.h
+++ b/llvm/lib/CodeGen/MachineTraceMetrics.h
@@ -226,6 +226,15 @@ public:
     /// When Bottom is set, instructions in the trace center block are included.
     unsigned getResourceDepth(bool Bottom) const;
 
+    /// Return the resource length of the trace. This is the number of cycles
+    /// required to execute the instructions in the trace if they were all
+    /// independent, exposing the maximum instruction-level parallelism.
+    ///
+    /// Any blocks in Extrablocks are included as if they were part of the
+    /// trace.
+    unsigned getResourceLength(ArrayRef<const MachineBasicBlock*> Extrablocks =
+                               ArrayRef<const MachineBasicBlock*>()) const;
+
     /// Return the length of the (data dependency) critical path through the
     /// trace.
     unsigned getCriticalPath() const { return TBI.CriticalPath; }
@@ -241,6 +250,10 @@ public:
     /// before the critical path becomes longer.
     /// MI must be an instruction in the trace center block.
     unsigned getInstrSlack(const MachineInstr *MI) const;
+
+    /// Return the Depth of a PHI instruction in a trace center block successor.
+    /// The PHI does not have to be part of the trace.
+    unsigned getPHIDepth(const MachineInstr *PHI) const;
   };
 
   /// A trace ensemble is a collection of traces selected using the same