[ARM] Add use-misched feature, to enable the MachineScheduler.

Summary:
This change makes it easier to experiment with the MachineScheduler in
the ARM backend and also makes it very explicit which CPUs use the
MachineScheduler (currently only swift and cyclone).



Reviewers: MatzeB, t.p.northover, javed.absar

Reviewed By: MatzeB

Subscribers: aemerson, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D35935

llvm-svn: 309316

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index e15b17512c9..400d185e9fd 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -180,6 +180,9 @@ protected:
   /// UseSoftFloat - True if we're using software floating point features.
   bool UseSoftFloat = false;
 
+  /// UseMISched - True if MachineScheduler should be used for this subtarget.
+  bool UseMISched = false;
+
   /// HasThumb2 - True if Thumb2 instructions are supported.
   bool HasThumb2 = false;
 
@@ -645,6 +648,7 @@ public:
   bool isROPI() const;
   bool isRWPI() const;
 
+  bool useMachineScheduler() const { return UseMISched; }
   bool useSoftFloat() const { return UseSoftFloat; }
   bool isThumb() const { return InThumbMode; }
   bool isThumb1Only() const { return InThumbMode && !HasThumb2; }