3 files changed, 47 insertions, 23 deletions

diff --git a/llvm/tools/llvm-mca/ExecuteStage.cpp b/llvm/tools/llvm-mca/ExecuteStage.cpp
index dadfd6548ed..f44bc7f04a8 100644
--- a/llvm/tools/llvm-mca/ExecuteStage.cpp
+++ b/llvm/tools/llvm-mca/ExecuteStage.cpp
@@ -16,7 +16,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "ExecuteStage.h"
-#include "Scheduler.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Debug.h"
 
@@ -26,11 +25,29 @@ namespace mca {
 
 using namespace llvm;
 
+HWStallEvent::GenericEventType toHWStallEventType(Scheduler::StallKind Event) {
+  switch (Event) {
+  case Scheduler::LoadQueueFull:
+    return HWStallEvent::LoadQueueFull;
+  case Scheduler::StoreQueueFull:
+    return HWStallEvent::StoreQueueFull;
+  case Scheduler::SchedulerQueueFull:
+    return HWStallEvent::SchedulerQueueFull;
+  case Scheduler::DispatchGroupStall:
+    return HWStallEvent::DispatchGroupStall;
+  case Scheduler::NoStall:
+    return HWStallEvent::Invalid;
+  }
+
+  llvm_unreachable("Don't know how to process this StallKind!");
+}
+
 bool ExecuteStage::isAvailable(const InstRef &IR) const {
-  HWStallEvent::GenericEventType Event;
+  Scheduler::StallKind Event = Scheduler::NoStall;
   if (HWS.canBeDispatched(IR, Event))
     return true;
-  notifyEvent<HWStallEvent>(HWStallEvent(Event, IR));
+  HWStallEvent::GenericEventType ET = toHWStallEventType(Event);
+  notifyEvent<HWStallEvent>(HWStallEvent(ET, IR));
   return false;
 }
 
diff --git a/llvm/tools/llvm-mca/Scheduler.cpp b/llvm/tools/llvm-mca/Scheduler.cpp
index f6b70d7cdf8..8597edf8717 100644
--- a/llvm/tools/llvm-mca/Scheduler.cpp
+++ b/llvm/tools/llvm-mca/Scheduler.cpp
@@ -258,27 +258,28 @@ void Scheduler::dump() const {
 #endif
 
 bool Scheduler::canBeDispatched(const InstRef &IR,
-                                HWStallEvent::GenericEventType &Event) const {
-  Event = HWStallEvent::Invalid;
+                                Scheduler::StallKind &Event) const {
+  Event = StallKind::NoStall;
   const InstrDesc &Desc = IR.getInstruction()->getDesc();
 
+  // Give lower priority to these stall events.
+  if (Desc.MayStore && LSU->isSQFull())
+    Event = StallKind::StoreQueueFull;
   if (Desc.MayLoad && LSU->isLQFull())
-    Event = HWStallEvent::LoadQueueFull;
-  else if (Desc.MayStore && LSU->isSQFull())
-    Event = HWStallEvent::StoreQueueFull;
-  else {
-    switch (Resources->canBeDispatched(Desc.Buffers)) {
-    default:
-      return true;
-    case ResourceStateEvent::RS_BUFFER_UNAVAILABLE:
-      Event = HWStallEvent::SchedulerQueueFull;
-      break;
-    case ResourceStateEvent::RS_RESERVED:
-      Event = HWStallEvent::DispatchGroupStall;
-    }
+    Event = StallKind::LoadQueueFull;
+    
+  switch (Resources->canBeDispatched(Desc.Buffers)) {
+  case ResourceStateEvent::RS_BUFFER_UNAVAILABLE:
+    Event = StallKind::SchedulerQueueFull;
+    break;
+  case ResourceStateEvent::RS_RESERVED:
+    Event = StallKind::DispatchGroupStall;
+    break;
+  default:
+    break;
   }
 
-  return false;
+  return Event == StallKind::NoStall;
 }
 
 void Scheduler::issueInstructionImpl(
diff --git a/llvm/tools/llvm-mca/Scheduler.h b/llvm/tools/llvm-mca/Scheduler.h
index 8d44f61e32b..ec7d5a05c38 100644
--- a/llvm/tools/llvm-mca/Scheduler.h
+++ b/llvm/tools/llvm-mca/Scheduler.h
@@ -15,11 +15,9 @@
 #ifndef LLVM_TOOLS_LLVM_MCA_SCHEDULER_H
 #define LLVM_TOOLS_LLVM_MCA_SCHEDULER_H
 
-#include "HWEventListener.h"
 #include "HardwareUnit.h"
 #include "Instruction.h"
 #include "LSUnit.h"
-#include "RetireControlUnit.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallVector.h"
@@ -387,14 +385,22 @@ public:
         LSU(llvm::make_unique<LSUnit>(LoadQueueSize, StoreQueueSize,
                                       AssumeNoAlias)) {}
 
+  // Stalls generated by the scheduler.
+  enum StallKind {
+    NoStall,
+    LoadQueueFull,
+    StoreQueueFull,
+    SchedulerQueueFull,
+    DispatchGroupStall
+  };
+
   /// Check if the instruction in 'IR' can be dispatched.
   ///
   /// The DispatchStage is responsible for querying the Scheduler before
   /// dispatching new instructions. This routine is used for performing such
   /// a query.  If the instruction 'IR' can be dispatched, then true is
   /// returned, otherwise false is returned with Event set to the stall type.
-  bool canBeDispatched(const InstRef &IR,
-                       HWStallEvent::GenericEventType &Event) const;
+  bool canBeDispatched(const InstRef &IR, StallKind &Event) const;
 
   /// Returns true if there is availibility for IR in the LSU.
   bool isReady(const InstRef &IR) const { return LSU->isReady(IR); }