Merge pull request #84846 from eeckstein/remove-speculative-devirtualization

Optimizer: remove the obsolete SpeculativeDevirtualization pass

Author: eeckstein

include/swift/AST/SILOptions.h

@@ -108,10 +108,6 @@ class SILOptions {
   /// purposes.
   bool EnableOSSAOptimizations = true;
 
-  /// Controls whether to turn on speculative devirtualization.
-  /// It is turned off by default.
-  bool EnableSpeculativeDevirtualization = false;
-
   /// Controls whether to emit actor data-race checks.
   bool EnableActorDataRaceChecks = false;
 

include/swift/Option/FrontendOptions.td

@@ -578,7 +578,7 @@ def disable_sil_partial_apply : Flag<["-"], "disable-sil-partial-apply">,
   HelpText<"Disable use of partial_apply in SIL generation">;
 
 def enable_spec_devirt : Flag<["-"], "enable-spec-devirt">,
-  HelpText<"Enable speculative devirtualization pass.">;
+  HelpText<"Deprecated, has no effect">;
 
 def enable_async_demotion : Flag<["-"], "enable-experimental-async-demotion">,
   HelpText<"Enables an optimization pass to demote async functions.">;

include/swift/SILOptimizer/PassManager/Passes.def

@@ -428,8 +428,6 @@ LEGACY_PASS(SimplifyBBArgs, "simplify-bb-args",
      "SIL Block Argument Simplification")
 LEGACY_PASS(SimplifyCFG, "simplify-cfg",
      "SIL CFG Simplification")
-LEGACY_PASS(SpeculativeDevirtualization, "specdevirt",
-     "Speculative Devirtualization via Guarded Calls")
 LEGACY_PASS(SplitAllCriticalEdges, "split-critical-edges",
      "Split all Critical Edges in the SIL CFG")
 LEGACY_PASS(SplitNonCondBrCriticalEdges, "split-non-cond_br-critical-edges",

lib/DriverTool/sil_opt_main.cpp

@@ -296,10 +296,6 @@ struct SILOptOptions {
   VerifyExclusivity = llvm::cl::opt<bool>("enable-verify-exclusivity",
                     llvm::cl::desc("Verify the access markers used to enforce exclusivity."));
 
-  llvm::cl::opt<bool>
-  EnableSpeculativeDevirtualization = llvm::cl::opt<bool>("enable-spec-devirt",
-                    llvm::cl::desc("Enable Speculative Devirtualization pass."));
-
   llvm::cl::opt<bool>
   EnableAsyncDemotion = llvm::cl::opt<bool>("enable-async-demotion",
                     llvm::cl::desc("Enables an optimization pass to demote async functions."));
@@ -891,7 +887,6 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
   SILOpts.EmitVerboseSIL |= options.EmitVerboseSIL;
   SILOpts.EmitSortedSIL |= options.EmitSortedSIL;
 
-  SILOpts.EnableSpeculativeDevirtualization = options.EnableSpeculativeDevirtualization;
   SILOpts.EnableAsyncDemotion = options.EnableAsyncDemotion;
   SILOpts.EnableThrowsPrediction = options.EnableThrowsPrediction;
   SILOpts.EnableNoReturnCold = options.EnableNoReturnCold;

lib/Frontend/CompilerInvocation.cpp

@@ -3081,7 +3081,6 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
   Opts.EnableOSSAOptimizations &= !Args.hasArg(OPT_disable_ossa_opts);
   Opts.EnableSILOpaqueValues = Args.hasFlag(
       OPT_enable_sil_opaque_values, OPT_disable_sil_opaque_values, false);
-  Opts.EnableSpeculativeDevirtualization |= Args.hasArg(OPT_enable_spec_devirt);
   Opts.EnableAsyncDemotion |= Args.hasArg(OPT_enable_async_demotion);
   Opts.EnableThrowsPrediction = Args.hasFlag(
       OPT_enable_throws_prediction, OPT_disable_throws_prediction,

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -795,11 +795,6 @@ static void addClosureSpecializePassPipeline(SILPassPipelinePlan &P) {
   // Do the second stack promotion on low-level SIL.
   P.addStackPromotion();
 
-  // Speculate virtual call targets.
-  if (P.getOptions().EnableSpeculativeDevirtualization) {
-    P.addSpeculativeDevirtualization();
-  }
-
   // There should be at least one SILCombine+SimplifyCFG between the
   // ClosureSpecializer, etc. and the last inliner. Cleaning up after these
   // passes can expose more inlining opportunities.

lib/SILOptimizer/Transforms/CMakeLists.txt

@@ -31,6 +31,5 @@ target_sources(swiftSILOptimizer PRIVATE
   DestroyAddrHoisting.cpp
   SimplifyCFG.cpp
   Sink.cpp
-  SpeculativeDevirtualizer.cpp
   StringOptimization.cpp)