From 5f22dd78584bfd0a1125d313d04660df2c9c3c47 Mon Sep 17 00:00:00 2001
From: Andrew Trick <atrick@apple.com>
Date: Wed, 4 Jun 2014 07:06:27 +0000
Subject: [PATCH] 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);

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210167 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/TargetSubtargetInfo.h | 7 +++++++
 lib/CodeGen/MachineScheduler.cpp          | 6 ++++++
 lib/CodeGen/Passes.cpp                    | 6 +++---
 lib/Target/ARM/ARMSubtarget.cpp           | 7 +++++++
 lib/Target/ARM/ARMSubtarget.h             | 3 +++
 lib/Target/TargetSubtargetInfo.cpp        | 4 ++++
 6 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/include/llvm/Target/TargetSubtargetInfo.h b/include/llvm/Target/TargetSubtargetInfo.h
index c0c342b22ec..bb164288b01 100644
--- a/include/llvm/Target/TargetSubtargetInfo.h
+++ b/include/llvm/Target/TargetSubtargetInfo.h
@@ -66,6 +66,13 @@ public:
   /// scheduler. It does not yet disable the postRA scheduler.
   virtual bool enableMachineScheduler() const;
 
+  /// \brief True if the subtarget should run PostMachineScheduler.
+  ///
+  /// This only takes effect if the target has configured the
+  /// PostMachineScheduler pass to run, or if the global cl::opt flag,
+  /// MISchedPostRA, is set.
+  virtual bool enablePostMachineScheduler() const;
+
   /// \brief Override generic scheduling policy within a region.
   ///
   /// This is a convenient way for targets that don't provide any custom
diff --git a/lib/CodeGen/MachineScheduler.cpp b/lib/CodeGen/MachineScheduler.cpp
index 6a0a3722ed3..734aba482b9 100644
--- a/lib/CodeGen/MachineScheduler.cpp
+++ b/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.
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index b3f719841db..9568e238a2c 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -92,9 +92,9 @@ PrintMachineInstrs("print-machineinstrs", cl::ValueOptional,
 
 // Temporary option to allow experimenting with MachineScheduler as a post-RA
 // scheduler. Targets can "properly" enable this with
-// substitutePass(&PostRASchedulerID, &MachineSchedulerID); Ideally it wouldn't
-// be part of the standard pass pipeline, and the target would just add a PostRA
-// scheduling pass wherever it wants.
+// substitutePass(&PostRASchedulerID, &PostMachineSchedulerID); Ideally it
+// wouldn't be part of the standard pass pipeline, and the target would just add
+// a PostRA scheduling pass wherever it wants.
 static cl::opt<bool> MISchedPostRA("misched-postra", cl::Hidden,
   cl::desc("Run MachineScheduler post regalloc (independent of preRA sched)"));
 
diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index 1c9dd4d49d6..61c00b5930c 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -352,6 +352,13 @@ bool ARMSubtarget::hasSinCos() const {
     !getTargetTriple().isOSVersionLT(7, 0);
 }
 
+// Enable the PostMachineScheduler if the target selects it instead of
+// PostRAScheduler. Currently only available on the command line via
+// -misched-postra.
+bool ARMSubtarget::enablePostMachineScheduler() const {
+  return PostRAScheduler;
+}
+
 bool ARMSubtarget::enablePostRAScheduler(
            CodeGenOpt::Level OptLevel,
            TargetSubtargetInfo::AntiDepBreakMode& Mode,
diff --git a/lib/Target/ARM/ARMSubtarget.h b/lib/Target/ARM/ARMSubtarget.h
index fd106f6fc86..2694c34293a 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -396,6 +396,9 @@ public:
   /// compiler runtime or math libraries.
   bool hasSinCos() const;
 
+  /// True for some subtargets at > -O0.
+  bool enablePostMachineScheduler() const;
+
   /// enablePostRAScheduler - True at 'More' optimization.
   bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
                              TargetSubtargetInfo::AntiDepBreakMode& Mode,
diff --git a/lib/Target/TargetSubtargetInfo.cpp b/lib/Target/TargetSubtargetInfo.cpp
index 3ca13dac035..0c388f8fb26 100644
--- a/lib/Target/TargetSubtargetInfo.cpp
+++ b/lib/Target/TargetSubtargetInfo.cpp
@@ -43,6 +43,10 @@ bool TargetSubtargetInfo::enableMachineScheduler() const {
   return false;
 }
 
+bool TargetSubtargetInfo::enablePostMachineScheduler() const {
+  return false;
+}
+
 bool TargetSubtargetInfo::enablePostRAScheduler(
           CodeGenOpt::Level OptLevel,
           AntiDepBreakMode& Mode,
-- 
2.34.1