1 files changed, 17 insertions, 38 deletions

diff --git a/llvm/tools/llvm-mca/Pipeline.cpp b/llvm/tools/llvm-mca/Pipeline.cpp
index 91c7a5d25ea..a67ae98d7cd 100644
--- a/llvm/tools/llvm-mca/Pipeline.cpp
+++ b/llvm/tools/llvm-mca/Pipeline.cpp
@@ -37,29 +37,6 @@ bool Pipeline::hasWorkToProcess() {
   });
 }
 
-// This routine returns early if any stage returns 'false' after execute() is
-// called on it.
-Stage::Status Pipeline::executeStages(InstRef &IR) {
-  for (const std::unique_ptr<Stage> &S : Stages) {
-    Stage::Status StatusOrErr = S->execute(IR);
-    if (!StatusOrErr)
-      return StatusOrErr.takeError();
-    else if (StatusOrErr.get() == Stage::Stop)
-      return Stage::Stop;
-  }
-  return Stage::Continue;
-}
-
-void Pipeline::preExecuteStages() {
-  for (const std::unique_ptr<Stage> &S : Stages)
-    S->preExecute();
-}
-
-void Pipeline::postExecuteStages() {
-  for (const std::unique_ptr<Stage> &S : Stages)
-    S->postExecute();
-}
-
 llvm::Error Pipeline::run() {
   assert(!Stages.empty() && "Unexpected empty pipeline found!");
 
@@ -74,36 +51,38 @@ llvm::Error Pipeline::run() {
 }
 
 llvm::Error Pipeline::runCycle() {
-  // Update stages before we start processing new instructions.
   llvm::Error Err = llvm::ErrorSuccess();
-  for (auto I = Stages.begin(), E = Stages.end(); I != E && !Err; ++I) {
+  // Update stages before we start processing new instructions.
+  for (auto I = Stages.rbegin(), E = Stages.rend(); I != E && !Err; ++I) {
     const std::unique_ptr<Stage> &S = *I;
     Err = S->cycleStart();
   }
 
-  if (Err)
-    return Err;
-
   // Now fetch and execute new instructions.
   InstRef IR;
-  while (true) {
-    preExecuteStages();
-    Stage::Status Val = executeStages(IR);
-    if (!Val)
-      return Val.takeError();
-    if (Val.get() == Stage::Stop)
-      break;
-    postExecuteStages();
-  }
+  Stage &FirstStage = *Stages[0];
+  while (!Err && FirstStage.isAvailable(IR))
+    Err = FirstStage.execute(IR);
 
   // Update stages in preparation for a new cycle.
-  for (auto I = Stages.begin(), E = Stages.end(); I != E && !Err; ++I) {
+  for (auto I = Stages.rbegin(), E = Stages.rend(); I != E && !Err; ++I) {
     const std::unique_ptr<Stage> &S = *I;
     Err = S->cycleEnd();
   }
+
   return Err;
 }
 
+void Pipeline::appendStage(std::unique_ptr<Stage> S) {
+  assert(S && "Invalid null stage in input!");
+  if (!Stages.empty()) {
+    Stage *Last = Stages.back().get();
+    Last->setNextInSequence(S.get());
+  }
+
+  Stages.push_back(std::move(S));
+}
+
 void Pipeline::notifyCycleBegin() {
   LLVM_DEBUG(dbgs() << "[E] Cycle begin: " << Cycles << '\n');
   for (HWEventListener *Listener : Listeners)