Add a subtarget hook: enablePostMachineScheduler.

As requested by AArch64 subtargets.

Note that this will have no effect until the
AArch64 target actually enables the pass like this:
substitutePass(&PostRASchedulerID, &PostMachineSchedulerID);

As soon as armv7 switches over, PostMachineScheduler will become the
default postRA scheduler, so this won't be necessary any more.
Targets using the old postRA schedule would then do:
substitutePass(&PostMachineSchedulerID, &PostRASchedulerID);

llvm-svn: 210167

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index 6a0a372..734aba4 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -333,6 +333,12 @@ bool PostMachineScheduler::runOnMachineFunction(MachineFunction &mf) {
   if (skipOptnoneFunction(*mf.getFunction()))
     return false;
 
+  const TargetSubtargetInfo &ST =
+    mf.getTarget().getSubtarget<TargetSubtargetInfo>();
+  if (!ST.enablePostMachineScheduler()) {
+    DEBUG(dbgs() << "Subtarget disables post-MI-sched.\n");
+    return false;
+  }
   DEBUG(dbgs() << "Before post-MI-sched:\n"; mf.print(dbgs()));
 
   // Initialize the context of the pass.