misched: Allow subtargets to enable misched and dependent options.

This allows me to begin enabling (or backing out) misched by default
for one subtarget at a time. To run misched we typically want to:
- Disable SelectionDAG scheduling (use the source order scheduler)
- Enable more aggressive coalescing (until we decide to always run the coalescer this way)
- Enable MachineScheduler pass itself.

Disabling PostRA sched may follow for some subtargets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167826 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index c314fa5b51..d63a5b7a3b 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -45,6 +45,7 @@
 #include "llvm/Target/TargetLowering.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
@@ -216,8 +217,9 @@ namespace llvm {
   ScheduleDAGSDNodes* createDefaultScheduler(SelectionDAGISel *IS,
                                              CodeGenOpt::Level OptLevel) {
     const TargetLowering &TLI = IS->getTargetLowering();
+    const TargetSubtargetInfo &ST = IS->TM.getSubtarget<TargetSubtargetInfo>();
 
-    if (OptLevel == CodeGenOpt::None ||
+    if (OptLevel == CodeGenOpt::None || ST.enableMachineScheduler() ||
         TLI.getSchedulingPreference() == Sched::Source)
       return createSourceListDAGScheduler(IS, OptLevel);
     if (TLI.getSchedulingPreference() == Sched::RegPressure)