4 files changed, 19 insertions, 4 deletions
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index c0861c58fd..84eb8b876f 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -236,7 +236,7 @@ TargetPassConfig::TargetPassConfig(TargetMachine *tm, PassManagerBase &pm)
 
   // Temporarily disable experimental passes.
   const TargetSubtargetInfo &ST = TM->getSubtarget<TargetSubtargetInfo>();
-  if (!ST.enableMachineScheduler())
+  if (!ST.useMachineScheduler())
     disablePass(&MachineSchedulerID);
 }
 
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index c776dd3122..791f1baf63 100644
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -2199,7 +2199,7 @@ bool RegisterCoalescer::runOnMachineFunction(MachineFunction &fn) {
 
   const TargetSubtargetInfo &ST = TM->getSubtarget<TargetSubtargetInfo>();
   if (EnableGlobalCopies == cl::BOU_UNSET)
-    JoinGlobalCopies = ST.enableMachineScheduler();
+    JoinGlobalCopies = ST.useMachineScheduler();
   else
     JoinGlobalCopies = (EnableGlobalCopies == cl::BOU_TRUE);
 
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 8369fd3a97..6d097a68f8 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -230,7 +230,7 @@ namespace llvm {
     const TargetLowering *TLI = IS->getTargetLowering();
     const TargetSubtargetInfo &ST = IS->TM.getSubtarget<TargetSubtargetInfo>();
 
-    if (OptLevel == CodeGenOpt::None || ST.enableMachineScheduler() ||
+    if (OptLevel == CodeGenOpt::None || ST.useMachineScheduler() ||
         TLI->getSchedulingPreference() == Sched::Source)
       return createSourceListDAGScheduler(IS, OptLevel);
     if (TLI->getSchedulingPreference() == Sched::RegPressure)
diff --git a/lib/Target/TargetSubtargetInfo.cpp b/lib/Target/TargetSubtargetInfo.cpp
index f624c321ab..10e8db5925 100644
--- a/lib/Target/TargetSubtargetInfo.cpp
+++ b/lib/Target/TargetSubtargetInfo.cpp
@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
 #include "llvm/ADT/SmallVector.h"
 using namespace llvm;
@@ -22,6 +23,21 @@ TargetSubtargetInfo::TargetSubtargetInfo() {}
 
 TargetSubtargetInfo::~TargetSubtargetInfo() {}
 
+// Temporary option to compare overall performance change when moving from the
+// SD scheduler to the MachineScheduler pass pipeline. It should be removed
+// before 3.4. The normal way to enable/disable the MachineScheduling pass
+// itself is by using -enable-misched. For targets that already use MI sched
+// (via MySubTarget::enableMachineScheduler()) -misched-bench=false negates the
+// subtarget hook.
+static cl::opt<bool> BenchMachineSched("misched-bench", cl::Hidden,
+    cl::desc("Migrate from the target's default SD scheduler to MI scheduler"));
+
+bool TargetSubtargetInfo::useMachineScheduler() const {
+  if (BenchMachineSched.getNumOccurrences())
+    return BenchMachineSched;
+  return enableMachineScheduler();
+}
+
 bool TargetSubtargetInfo::enableMachineScheduler() const {
   return false;
 }
@@ -38,4 +54,3 @@ bool TargetSubtargetInfo::enablePostRAScheduler(
 bool TargetSubtargetInfo::useAA() const {
   return false;
 }
-