Count processor resources individually in MachineTraceMetrics.

The new instruction scheduling models provide information about the
number of cycles consumed on each processor resource. This makes it
possible to estimate ILP more accurately than simply counting
instructions / issue width.

The functions getResourceDepth() and getResourceLength() now identify
the limiting processor resource, and return a cycle count based on that.

This gives more precise resource information, particularly in traces
that use one resource a lot more than others.

llvm-svn: 178553

1 files changed, 25 insertions, 0 deletions

diff --git a/llvm/include/llvm/CodeGen/MachineTraceMetrics.h b/llvm/include/llvm/CodeGen/MachineTraceMetrics.h
index eaaa70a67d8..2775a048582 100644
--- a/llvm/include/llvm/CodeGen/MachineTraceMetrics.h
+++ b/llvm/include/llvm/CodeGen/MachineTraceMetrics.h
@@ -107,6 +107,13 @@ public:
   /// Get the fixed resource information about MBB. Compute it on demand.
   const FixedBlockInfo *getResources(const MachineBasicBlock*);
 
+  /// Get the scaled number of cycles used per processor resource in MBB.
+  /// This is an array with SchedModel.getNumProcResourceKinds() entries.
+  /// The getResources() function above must have been called first.
+  ///
+  /// These numbers have already been scaled by SchedModel.getResourceFactor().
+  ArrayRef<unsigned> getProcResourceCycles(unsigned MBBNum) const;
+
   /// A virtual register or regunit required by a basic block or its trace
   /// successors.
   struct LiveInReg {
@@ -284,6 +291,8 @@ public:
   class Ensemble {
     SmallVector<TraceBlockInfo, 4> BlockInfo;
     DenseMap<const MachineInstr*, InstrCycles> Cycles;
+    SmallVector<unsigned, 0> ProcResourceDepths;
+    SmallVector<unsigned, 0> ProcResourceHeights;
     friend class Trace;
 
     void computeTrace(const MachineBasicBlock*);
@@ -303,6 +312,8 @@ public:
     const MachineLoop *getLoopFor(const MachineBasicBlock*) const;
     const TraceBlockInfo *getDepthResources(const MachineBasicBlock*) const;
     const TraceBlockInfo *getHeightResources(const MachineBasicBlock*) const;
+    ArrayRef<unsigned> getProcResourceDepths(unsigned MBBNum) const;
+    ArrayRef<unsigned> getProcResourceHeights(unsigned MBBNum) const;
 
   public:
     virtual ~Ensemble();
@@ -343,8 +354,22 @@ private:
   // One entry per basic block, indexed by block number.
   SmallVector<FixedBlockInfo, 4> BlockInfo;
 
+  // Cycles consumed on each processor resource per block.
+  // The number of processor resource kinds is constant for a given subtarget,
+  // but it is not known at compile time. The number of cycles consumed by
+  // block B on processor resource R is at ProcResourceCycles[B*Kinds + R]
+  // where Kinds = SchedModel.getNumProcResourceKinds().
+  SmallVector<unsigned, 0> ProcResourceCycles;
+
   // One ensemble per strategy.
   Ensemble* Ensembles[TS_NumStrategies];
+
+  // Convert scaled resource usage to a cycle count that can be compared with
+  // latencies.
+  unsigned getCycles(unsigned Scaled) {
+    unsigned Factor = SchedModel.getLatencyFactor();
+    return (Scaled + Factor - 1) / Factor;
+  }
 };
 
 inline raw_ostream &operator<<(raw_ostream &OS,