Revert "Optimizer: improve the load-copy-to-borrow optimization and implement it in swift"

This reverts commit eed8645.

Author: eeckstein

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/CMakeLists.txt

@@ -22,7 +22,6 @@ swift_compiler_sources(Optimizer
   LifetimeDependenceDiagnostics.swift
   LifetimeDependenceInsertion.swift
   LifetimeDependenceScopeFixup.swift
-  LoadCopyToBorrowOptimization.swift
   ObjectOutliner.swift
   ObjCBridgingOptimization.swift
   MergeCondFails.swift

SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LoadCopyToBorrowOptimization.swift

@@ -95,7 +95,6 @@ private func registerSwiftPasses() {
   registerPass(lifetimeDependenceDiagnosticsPass, { lifetimeDependenceDiagnosticsPass.run($0) })
   registerPass(lifetimeDependenceInsertionPass, { lifetimeDependenceInsertionPass.run($0) })
   registerPass(lifetimeDependenceScopeFixupPass, { lifetimeDependenceScopeFixupPass.run($0) })
-  registerPass(loadCopyToBorrowOptimization, { loadCopyToBorrowOptimization.run($0) })
   registerPass(generalClosureSpecialization, { generalClosureSpecialization.run($0) })
   registerPass(autodiffClosureSpecialization, { autodiffClosureSpecialization.run($0) })
 

SwiftCompilerSources/Sources/Optimizer/PassManager/PassRegistration.swift

@@ -173,8 +173,6 @@ PASS(CopyPropagation, "copy-propagation",
      "Copy propagation to Remove Redundant SSA Copies, pruning debug info")
 PASS(MandatoryCopyPropagation, "mandatory-copy-propagation",
      "Copy propagation to Remove Redundant SSA Copies, preserving debug info")
-SWIFT_FUNCTION_PASS(LoadCopyToBorrowOptimization, "load-copy-to-borrow-optimization",
-     "Convert load [copy] instructions to load_borrow")
 PASS(COWOpts, "cow-opts",
      "Optimize COW operations")
 PASS(Differentiation, "differentiation",

include/swift/SILOptimizer/PassManager/Passes.def

@@ -517,7 +517,6 @@ void addFunctionPasses(SILPassPipelinePlan &P,
     P.addCopyPropagation();
   }
   P.addSemanticARCOpts();
-  P.addLoadCopyToBorrowOptimization();
 
   if (!P.getOptions().EnableOSSAModules) {
     if (P.getOptions().StopOptimizationBeforeLoweringOwnership)
@@ -547,7 +546,6 @@ void addFunctionPasses(SILPassPipelinePlan &P,
       P.addCopyPropagation();
     }
     P.addSemanticARCOpts();
-    P.addLoadCopyToBorrowOptimization();
   }
 
   // Promote stack allocations to values and eliminate redundant
@@ -576,7 +574,6 @@ void addFunctionPasses(SILPassPipelinePlan &P,
   }
   // Optimize copies created during RLE.
   P.addSemanticARCOpts();
-  P.addLoadCopyToBorrowOptimization();
 
   P.addCOWOpts();
   P.addPerformanceConstantPropagation();
@@ -614,7 +611,6 @@ void addFunctionPasses(SILPassPipelinePlan &P,
       P.addCopyPropagation();
     }
     P.addSemanticARCOpts();
-    P.addLoadCopyToBorrowOptimization();
   }
 }
 
@@ -652,7 +648,6 @@ static void addPerfEarlyModulePassPipeline(SILPassPipelinePlan &P) {
     P.addCopyPropagation();
   }
   P.addSemanticARCOpts();
-  P.addLoadCopyToBorrowOptimization();
 
   // Devirtualizes differentiability witnesses into functions that reference them.
   // This unblocks many other passes' optimizations (e.g. inlining) and this is
@@ -999,7 +994,6 @@ SILPassPipelinePlan::getPerformancePassPipeline(const SILOptions &Options) {
       P.addCopyPropagation();
     }
     P.addSemanticARCOpts();
-    P.addLoadCopyToBorrowOptimization();
   }
 
   P.addCrossModuleOptimization();

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -1,6 +1,7 @@
 target_sources(swiftSILOptimizer PRIVATE
   SemanticARCOpts.cpp
   OwnershipLiveRange.cpp
+  LoadCopyToLoadBorrowOpt.cpp
   BorrowScopeOpts.cpp
   CopyValueOpts.cpp
   OwnedToGuaranteedPhiOpt.cpp