Revert "Add a stack promotion optimization."

This reverts commit 0dd045c.

StackPromotion crashes when compiling MatMult in stdlib-asserts configuration

include/swift/LLVMPasses/Passes.h

@@ -88,15 +88,6 @@ namespace swift {
     SwiftARCContract() : llvm::FunctionPass(ID) {}
   };
 
-  class SwiftStackPromotion : public llvm::FunctionPass {
-    virtual void getAnalysisUsage(llvm::AnalysisUsage &AU) const override;
-    virtual bool runOnFunction(llvm::Function &F) override;
-  public:
-    static char ID;
-    SwiftStackPromotion() : llvm::FunctionPass(ID) {}
-  };
-
-
 } // end namespace swift
 
 #endif

include/swift/LLVMPasses/PassesFwd.h

@@ -22,13 +22,11 @@ namespace llvm {
   void initializeSwiftRCIdentityPass(PassRegistry &);
   void initializeSwiftARCOptPass(PassRegistry &);
   void initializeSwiftARCContractPass(PassRegistry &);
-  void initializeSwiftStackPromotionPass(PassRegistry &);
 }
 
 namespace swift {
   llvm::FunctionPass *createSwiftARCOptPass();
   llvm::FunctionPass *createSwiftARCContractPass();
-  llvm::FunctionPass *createSwiftStackPromotionPass();
   llvm::ImmutablePass *createSwiftAAWrapperPass();
   llvm::ImmutablePass *createSwiftRCIdentityPass();
 } // end namespace swift

include/swift/SILPasses/Passes.def

@@ -166,8 +166,6 @@ PASS(SplitAllCriticalEdges, "split-critical-edges",
      "Split all critical edges")
 PASS(SplitNonCondBrCriticalEdges, "split-non-cond_br-critical-edges",
      "Split all critical edges that do not involve cond_br")
-PASS(StackPromotion, "stack-promotion",
-     "Promote allocated objects on the stack")
 PASS(StripDebugInfo, "strip-debug-info",
      "Strip debug info")
 PASS(SwiftArrayOpts, "array-specialize",

lib/IRGen/IRGen.cpp

@@ -74,12 +74,6 @@ static void addSwiftContractPass(const PassManagerBuilder &Builder,
     PM.add(createSwiftARCContractPass());
 }
 
-static void addSwiftStackPromotionPass(const PassManagerBuilder &Builder,
-                                       PassManagerBase &PM) {
-  if (Builder.OptLevel > 0)
-    PM.add(createSwiftStackPromotionPass());
-}
-
 // FIXME: Copied from clang/lib/CodeGen/CGObjCMac.cpp. 
 // These should be moved to a single definition shared by clang and swift.
 enum ImageInfoFlags {
@@ -131,9 +125,6 @@ void swift::performLLVMOptimizations(IRGenOptions &Opts, llvm::Module *Module,
         llvm::createAlwaysInlinerPass(/*insertlifetime*/false);
   }
 
-  PMBuilder.addExtension(PassManagerBuilder::EP_ModuleOptimizerEarly,
-                         addSwiftStackPromotionPass);
-
   // If the optimizer is enabled, we run the ARCOpt pass in the scalar optimizer
   // and the Contract pass as late as possible.
   if (!Opts.DisableLLVMARCOpts) {

lib/LLVMPasses/CMakeLists.txt

@@ -3,7 +3,6 @@ add_swift_library(swiftLLVMPasses
   LLVMSwiftRCIdentity.cpp
   LLVMARCOpts.cpp
   LLVMARCContract.cpp
-  LLVMStackPromotion.cpp
   )
 
 add_dependencies(swiftLLVMPasses LLVMAnalysis)

lib/SILPasses/CMakeLists.txt

@@ -49,6 +49,5 @@ add_swift_library(swiftSILPasses
   SimplifyCFG.cpp
   Sink.cpp
   SpeculativeDevirtualizer.cpp
-  StackPromotion.cpp
   UsePrespecialized.cpp
   LINK_LIBRARIES swiftSILPassesUtils swiftSILAnalysis)

lib/SILPasses/Passes.cpp

@@ -255,9 +255,6 @@ void swift::runSILOptimizationPasses(SILModule &Module) {
   PM.addGlobalPropertyOpt();
   PM.addUpdateEscapeAnalysis();
 
-  // Do the first stack promotion on high-level SIL.
-  PM.addStackPromotion();
-
   PM.runOneIteration();
   PM.resetAndRemoveTransformations();
 
@@ -292,9 +289,6 @@ void swift::runSILOptimizationPasses(SILModule &Module) {
 
   PM.addUpdateEscapeAnalysis();
 
-  // Do the first stack promotion on low-level SIL.
-  PM.addStackPromotion();
-
   // Speculate virtual call targets.
   PM.addSpeculativeDevirtualization();