Perform alloca coloring only at -O1 and higher.

3 files changed, 18 insertions, 8 deletions

diff --git a/lib/Target/JSBackend/AllocaManager.cpp b/lib/Target/JSBackend/AllocaManager.cpp
index 6c4c49f0d0..4673a34644 100644
--- a/lib/Target/JSBackend/AllocaManager.cpp
+++ b/lib/Target/JSBackend/AllocaManager.cpp
@@ -450,7 +450,8 @@ void AllocaManager::computeFrameOffsets() {
 AllocaManager::AllocaManager() {
 }
 
-void AllocaManager::analyze(const Function &Func, const DataLayout &Layout) {
+void AllocaManager::analyze(const Function &Func, const DataLayout &Layout,
+                            bool PerformColoring) {
   NamedRegionTimer Timer("AllocaManager", TimePassesIsEnabled);
 
   assert(Allocas.empty());
@@ -469,8 +470,11 @@ void AllocaManager::analyze(const Function &Func, const DataLayout &Layout) {
   LifetimeStart = M->getFunction(Intrinsic::getName(Intrinsic::lifetime_start));
   LifetimeEnd = M->getFunction(Intrinsic::getName(Intrinsic::lifetime_end));
 
-  if ((LifetimeStart && !LifetimeStart->use_empty()) ||
-      (LifetimeEnd   && !LifetimeEnd->use_empty())) {
+  // If we are optimizing and the module contains any lifetime intrinsics, run
+  // the alloca coloring algorithm.
+  if (PerformColoring &&
+      ((LifetimeStart && !LifetimeStart->use_empty()) ||
+       (LifetimeEnd   && !LifetimeEnd->use_empty()))) {
 
     collectMarkedAllocas();
 
diff --git a/lib/Target/JSBackend/AllocaManager.h b/lib/Target/JSBackend/AllocaManager.h
index 0aafeb4a06..44b07981bc 100644
--- a/lib/Target/JSBackend/AllocaManager.h
+++ b/lib/Target/JSBackend/AllocaManager.h
@@ -144,8 +144,9 @@ class AllocaManager {
 public:
   AllocaManager();
 
-  /// Analyze the given function and prepare for getReplacement queries.
-  void analyze(const Function &Func, const DataLayout &Layout);
+  /// Analyze the given function and prepare for getRepresentative queries.
+  void analyze(const Function &Func, const DataLayout &Layout,
+               bool PerformColoring);
 
   /// Reset all stored state.
   void clear();
diff --git a/lib/Target/JSBackend/JSBackend.cpp b/lib/Target/JSBackend/JSBackend.cpp
index b440980010..9bc1764042 100644
--- a/lib/Target/JSBackend/JSBackend.cpp
+++ b/lib/Target/JSBackend/JSBackend.cpp
@@ -139,13 +139,16 @@ namespace {
 
     bool UsesSIMD;
     int InvokeState; // cycles between 0, 1 after preInvoke, 2 after call, 0 again after postInvoke. hackish, no argument there.
+    CodeGenOpt::Level OptLevel;
     DataLayout *DL;
 
     #include "CallHandlers.h"
 
   public:
     static char ID;
-    explicit JSWriter(formatted_raw_ostream &o) : ModulePass(ID), Out(o), UniqueNum(0), UsesSIMD(false), InvokeState(0) {}
+    JSWriter(formatted_raw_ostream &o, CodeGenOpt::Level OptLevel)
+      : ModulePass(ID), Out(o), UniqueNum(0), UsesSIMD(false), InvokeState(0),
+        OptLevel(OptLevel) {}
 
     virtual const char *getPassName() const { return "JavaScript backend"; }
 
@@ -1847,7 +1850,9 @@ void JSWriter::printFunction(const Function *F) {
   UsedVars.clear();
   UniqueNum = 0;
   calculateNativizedVars(F);
-  Allocas.analyze(*F, *DL);
+
+  // Do alloca coloring at -O1 and higher.
+  Allocas.analyze(*F, *DL, OptLevel != CodeGenOpt::None);
 
   // Emit the function
 
@@ -2335,7 +2340,7 @@ bool JSTargetMachine::addPassesToEmitFile(PassManagerBase &PM,
 
   PM.add(createExpandI64Pass());
   PM.add(createSimplifyAllocasPass());
-  PM.add(new JSWriter(o));
+  PM.add(new JSWriter(o, getOptLevel()));
 
   return false;
 }