[Sched] Auto add MacroFusion mutation if enabled

We can get the information by `enableMacroFusion`.

Author: wangpc-pp

llvm/lib/CodeGen/MachineScheduler.cpp

@@ -3791,6 +3791,11 @@ ScheduleDAGMILive *llvm::createGenericSchedLive(MachineSchedContext *C) {
   // data and pass it to later mutations. Have a single mutation that gathers
   // the interesting nodes in one pass.
   DAG->addMutation(createCopyConstrainDAGMutation(DAG->TII, DAG->TRI));
+
+  const TargetSubtargetInfo &STI = C->MF->getSubtarget();
+  // Add MacroFusionDAGMutation if enabled.
+  if (STI.enableMacroFusion())
+    DAG->addMutation(createMacroFusionDAGMutation(STI.getMacroFusions()));
   return DAG;
 }
 
@@ -3940,8 +3945,14 @@ void PostGenericScheduler::schedNode(SUnit *SU, bool IsTopNode) {
 }
 
 ScheduleDAGMI *llvm::createGenericSchedPostRA(MachineSchedContext *C) {
-  return new ScheduleDAGMI(C, std::make_unique<PostGenericScheduler>(C),
-                           /*RemoveKillFlags=*/true);
+  ScheduleDAGMI *DAG =
+      new ScheduleDAGMI(C, std::make_unique<PostGenericScheduler>(C),
+                        /*RemoveKillFlags=*/true);
+  const TargetSubtargetInfo &STI = C->MF->getSubtarget();
+  // Add MacroFusionDAGMutation if enabled.
+  if (STI.enableMacroFusion())
+    DAG->addMutation(createMacroFusionDAGMutation(STI.getMacroFusions()));
+  return DAG;
 }
 
 //===----------------------------------------------------------------------===//

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -343,28 +343,6 @@ class RISCVPassConfig : public TargetPassConfig {
     return getTM<RISCVTargetMachine>();
   }
 
-  ScheduleDAGInstrs *
-  createMachineScheduler(MachineSchedContext *C) const override {
-    const RISCVSubtarget &ST = C->MF->getSubtarget<RISCVSubtarget>();
-    if (ST.enableMacroFusion()) {
-      ScheduleDAGMILive *DAG = createGenericSchedLive(C);
-      DAG->addMutation(createMacroFusionDAGMutation(ST.getMacroFusions()));
-      return DAG;
-    }
-    return nullptr;
-  }
-
-  ScheduleDAGInstrs *
-  createPostMachineScheduler(MachineSchedContext *C) const override {
-    const RISCVSubtarget &ST = C->MF->getSubtarget<RISCVSubtarget>();
-    if (ST.enableMacroFusion()) {
-      ScheduleDAGMI *DAG = createGenericSchedPostRA(C);
-      DAG->addMutation(createMacroFusionDAGMutation(ST.getMacroFusions()));
-      return DAG;
-    }
-    return nullptr;
-  }
-
   void addIRPasses() override;
   bool addPreISel() override;
   bool addInstSelector() override;