[llvm-commits] [llvm] r161471 - in /llvm/trunk: include/llvm/MC/MCSchedule.h include/llvm/Target/TargetSchedule.td lib/Target/ARM/ARMScheduleA8.td lib/Target/ARM/ARMScheduleA9.td lib/Target/ARM/ARMSubtarget.cpp lib/Target/ARM/ARMSubtarget.h utils/TableGen/SubtargetEmitter.cpp

Andrew Trick atrick at apple.com
Tue Aug 7 19:44:16 PDT 2012


Author: atrick
Date: Tue Aug  7 21:44:16 2012
New Revision: 161471

URL: http://llvm.org/viewvc/llvm-project?rev=161471&view=rev
Log:
Added MispredictPenalty to SchedMachineModel.

This replaces an existing subtarget hook on ARM and allows standard
CodeGen passes to potentially use the property.

Modified:
    llvm/trunk/include/llvm/MC/MCSchedule.h
    llvm/trunk/include/llvm/Target/TargetSchedule.td
    llvm/trunk/lib/Target/ARM/ARMScheduleA8.td
    llvm/trunk/lib/Target/ARM/ARMScheduleA9.td
    llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
    llvm/trunk/lib/Target/ARM/ARMSubtarget.h
    llvm/trunk/utils/TableGen/SubtargetEmitter.cpp

Modified: llvm/trunk/include/llvm/MC/MCSchedule.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCSchedule.h?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCSchedule.h (original)
+++ llvm/trunk/include/llvm/MC/MCSchedule.h Tue Aug  7 21:44:16 2012
@@ -78,6 +78,11 @@
   unsigned HighLatency;
   static const unsigned DefaultHighLatency = 10;
 
+  // MispredictPenalty is the typical number of extra cycles the processor
+  // takes to recover from a branch misprediction.
+  unsigned MispredictPenalty;
+  static const unsigned DefaultMispredictPenalty = 10;
+
 private:
   // TODO: Add a reference to proc resource types and sched resource tables.
 
@@ -94,13 +99,14 @@
                   MinLatency(DefaultMinLatency),
                   LoadLatency(DefaultLoadLatency),
                   HighLatency(DefaultHighLatency),
+                  MispredictPenalty(DefaultMispredictPenalty),
                   InstrItineraries(0) {}
 
   // Table-gen driven ctor.
-  MCSchedModel(unsigned iw, int ml, unsigned ll, unsigned hl,
+  MCSchedModel(unsigned iw, int ml, unsigned ll, unsigned hl, unsigned mp,
                const InstrItinerary *ii):
     IssueWidth(iw), MinLatency(ml), LoadLatency(ll), HighLatency(hl),
-    InstrItineraries(ii){}
+    MispredictPenalty(mp), InstrItineraries(ii){}
 };
 
 } // End llvm namespace

Modified: llvm/trunk/include/llvm/Target/TargetSchedule.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetSchedule.td?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetSchedule.td (original)
+++ llvm/trunk/include/llvm/Target/TargetSchedule.td Tue Aug  7 21:44:16 2012
@@ -27,6 +27,7 @@
                        // (-1) inorder (0) ooo, (1): inorder +var latencies.
   int LoadLatency = -1; // Cycles for loads to access the cache.
   int HighLatency = -1; // Approximation of cycles for "high latency" ops.
+  int MispredictPenalty = -1; // Extra cycles for a mispredicted branch.
 
   ProcessorItineraries Itineraries = NoItineraries;
 

Modified: llvm/trunk/lib/Target/ARM/ARMScheduleA8.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMScheduleA8.td?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMScheduleA8.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMScheduleA8.td Tue Aug  7 21:44:16 2012
@@ -1069,6 +1069,7 @@
   let LoadLatency = 2; // Optimistic load latency assuming bypass.
                        // This is overriden by OperandCycles if the
                        // Itineraries are queried instead.
+  let MispredictPenalty = 13; // Based on estimate of pipeline depth.
 
   let Itineraries = CortexA8Itineraries;
 }

Modified: llvm/trunk/lib/Target/ARM/ARMScheduleA9.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMScheduleA9.td?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMScheduleA9.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMScheduleA9.td Tue Aug  7 21:44:16 2012
@@ -1886,6 +1886,7 @@
   let LoadLatency = 2; // Optimistic load latency assuming bypass.
                        // This is overriden by OperandCycles if the
                        // Itineraries are queried instead.
+  let MispredictPenalty = 8; // Based on estimate of pipeline depth.
 
   let Itineraries = CortexA9Itineraries;
 }

Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp Tue Aug  7 21:44:16 2012
@@ -97,6 +97,9 @@
   if (!HasV6T2Ops && hasThumb2())
     HasV4TOps = HasV5TOps = HasV5TEOps = HasV6Ops = HasV6T2Ops = true;
 
+  // Keep a pointer to static instruction cost data for the specified CPU.
+  SchedModel = getSchedModelForCPU(CPUString);
+
   // Initialize scheduling itinerary for the specified CPU.
   InstrItins = getInstrItineraryForCPU(CPUString);
 
@@ -179,15 +182,7 @@
 }
 
 unsigned ARMSubtarget::getMispredictionPenalty() const {
-  // If we have a reasonable estimate of the pipeline depth, then we can
-  // estimate the penalty of a misprediction based on that.
-  if (isCortexA8())
-    return 13;
-  else if (isCortexA9())
-    return 8;
-
-  // Otherwise, just return a sensible default.
-  return 10;
+  return SchedModel->MispredictPenalty;
 }
 
 bool ARMSubtarget::enablePostRAScheduler(

Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.h?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMSubtarget.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMSubtarget.h Tue Aug  7 21:44:16 2012
@@ -155,6 +155,9 @@
   /// TargetTriple - What processor and OS we're targeting.
   Triple TargetTriple;
 
+  /// SchedModel - Processor specific instruction costs.
+  const MCSchedModel *SchedModel;
+
   /// Selected instruction itineraries (one entry per itinerary class.)
   InstrItineraryData InstrItins;
 

Modified: llvm/trunk/utils/TableGen/SubtargetEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/SubtargetEmitter.cpp?rev=161471&r1=161470&r2=161471&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/SubtargetEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/SubtargetEmitter.cpp Tue Aug  7 21:44:16 2012
@@ -590,6 +590,7 @@
     EmitProcessorProp(OS, PI->ModelDef, "MinLatency", ',');
     EmitProcessorProp(OS, PI->ModelDef, "LoadLatency", ',');
     EmitProcessorProp(OS, PI->ModelDef, "HighLatency", ',');
+    EmitProcessorProp(OS, PI->ModelDef, "MispredictPenalty", ',');
     if (SchedModels.hasItineraryClasses())
       OS << "  " << PI->ItinsDef->getName();
     else





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