[llvm] r190558 - Enable MI scheduling (and CodeGen AA) by default for embedded PPC cores

[Hal Finkel]

Author: hfinkel
Date: Wed Sep 11 18:05:25 2013
New Revision: 190558

URL: http://llvm.org/viewvc/llvm-project?rev=190558&view=rev
Log:
Enable MI scheduling (and CodeGen AA) by default for embedded PPC cores

For embedded PPC cores (especially the A2 core), using the MI scheduler with AA
is far superior to the other scheduling options.

Modified:
    llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
    llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp
    llvm/trunk/lib/Target/PowerPC/PPCSubtarget.h

Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=190558&r1=190557&r2=190558&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Wed Sep 11 18:05:25 2013
@@ -556,7 +556,10 @@ PPCTargetLowering::PPCTargetLowering(PPC
 
   setInsertFencesForAtomic(true);
 
-  setSchedulingPreference(Sched::Hybrid);
+  if (Subtarget->enableMachineScheduler())
+    setSchedulingPreference(Sched::Source);
+  else
+    setSchedulingPreference(Sched::Hybrid);
 
   computeRegisterProperties();
 
@@ -7853,7 +7856,7 @@ bool PPCTargetLowering::isFMAFasterThanF
 }
 
 Sched::Preference PPCTargetLowering::getSchedulingPreference(SDNode *N) const {
-  if (DisableILPPref)
+  if (DisableILPPref || PPCSubTarget.enableMachineScheduler())
     return TargetLowering::getSchedulingPreference(N);
 
   return Sched::ILP;

Modified: llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp?rev=190558&r1=190557&r2=190558&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCSubtarget.cpp Wed Sep 11 18:05:25 2013
@@ -15,6 +15,7 @@
 #include "PPC.h"
 #include "PPCRegisterInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineScheduler.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Function.h"
@@ -186,3 +187,41 @@ bool PPCSubtarget::enablePostRAScheduler
   return OptLevel >= CodeGenOpt::Default;
 }
 
+// Embedded cores need aggressive scheduling.
+static bool needsAggressiveScheduling(unsigned Directive) {
+  switch (Directive) {
+  default: return false;
+  case PPC::DIR_440:
+  case PPC::DIR_A2:
+  case PPC::DIR_E500mc:
+  case PPC::DIR_E5500:
+    return true;
+  }
+}
+
+bool PPCSubtarget::enableMachineScheduler() const {
+  // Enable MI scheduling for the embedded cores.
+  // FIXME: Enable this for all cores (some additional modeling
+  // may be necessary).
+  return needsAggressiveScheduling(DarwinDirective);
+}
+
+void PPCSubtarget::overrideSchedPolicy(MachineSchedPolicy &Policy,
+                                       MachineInstr *begin,
+                                       MachineInstr *end,
+                                       unsigned NumRegionInstrs) const {
+  if (needsAggressiveScheduling(DarwinDirective)) {
+    Policy.OnlyTopDown = false;
+    Policy.OnlyBottomUp = false;
+  }
+
+  // Spilling is generally expensive on all PPC cores, so always enable
+  // register-pressure tracking.
+  Policy.ShouldTrackPressure = true;
+}
+
+bool PPCSubtarget::useAA() const {
+  // Use AA during code generation for the embedded cores.
+  return needsAggressiveScheduling(DarwinDirective);
+}
+

Modified: llvm/trunk/lib/Target/PowerPC/PPCSubtarget.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCSubtarget.h?rev=190558&r1=190557&r2=190558&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCSubtarget.h (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCSubtarget.h Wed Sep 11 18:05:25 2013
@@ -207,6 +207,14 @@ public:
   bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
                              TargetSubtargetInfo::AntiDepBreakMode& Mode,
                              RegClassVector& CriticalPathRCs) const;
+
+  // Scheduling customization.
+  bool enableMachineScheduler() const;
+  void overrideSchedPolicy(MachineSchedPolicy &Policy,
+                           MachineInstr *begin,
+                           MachineInstr *end,
+                           unsigned NumRegionInstrs) const;
+  bool useAA() const;
 };
 } // End llvm namespace