[CodeGen] Run machine optimizations once

13 files changed, 21 insertions, 217 deletions

diff --git a/backend/include/rcc/CodeGen/MachineCombiner.h b/backend/include/rcc/CodeGen/MachineCombiner.h
index 42ca301..d9df1d1 100644
--- a/backend/include/rcc/CodeGen/MachineCombiner.h
+++ b/backend/include/rcc/CodeGen/MachineCombiner.h
@@ -29,7 +29,8 @@ public:
 private:
   [[nodiscard]] Expected<MachinePassResult> runImplementation(MachineFunction &Function,
                                                               const TargetDescription &Target,
-                                                              MachineActionReplay &Actions) const;
+                                                              MachineFunctionAnalysisManager
+                                                                  &Analyses) const;
 
   const TargetMachineCombinerInfo *Info;
   MachineCombinerOptions Options;
diff --git a/backend/include/rcc/CodeGen/MachineCopyPropagation.h b/backend/include/rcc/CodeGen/MachineCopyPropagation.h
index 59a3a77..e689632 100644
--- a/backend/include/rcc/CodeGen/MachineCopyPropagation.h
+++ b/backend/include/rcc/CodeGen/MachineCopyPropagation.h
@@ -30,7 +30,8 @@ public:
 private:
   [[nodiscard]] Expected<MachinePassResult> runImplementation(MachineFunction &Function,
                                                               const TargetDescription &Target,
-                                                              MachineActionReplay &Actions) const;
+                                                              MachineFunctionAnalysisManager
+                                                                  &Analyses) const;
 
   const TargetInstrInfo *Info;
   MachineCopyPropagationOptions Options;
diff --git a/backend/lib/CodeGen/MachineBranchOptimization.cpp b/backend/lib/CodeGen/MachineBranchOptimization.cpp
index e03b0d9..6e3bc17 100644
--- a/backend/lib/CodeGen/MachineBranchOptimization.cpp
+++ b/backend/lib/CodeGen/MachineBranchOptimization.cpp
@@ -8,7 +8,6 @@
 #include "rcc/CodeGen/MachineBasicBlockAttributes.h"
 #include "rcc/CodeGen/MachineCFGUpdater.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineFunctionRecords.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineJumpTableInfo.h"
@@ -21,7 +20,6 @@
 #include <algorithm>
 #include <cstddef>
 #include <cstdint>
-#include <optional>
 #include <ranges>
 #include <string>
 #include <unordered_set>
@@ -581,22 +579,7 @@ const MachinePassContract &MachineBranchOptimizationPass::contract() const noexc
 Expected<MachinePassResult> MachineBranchOptimizationPass::run(MachineFunction &Function,
                                                                const TargetDescription &Target,
                                                                MachineFunctionAnalysisManager &) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "branch optimization transaction setup failed: "));
-  }
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-  auto Result = runImplementation(Function, Target);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "branch optimization diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachineCSE.cpp b/backend/lib/CodeGen/MachineCSE.cpp
index 50dca0e..7bd5a22 100644
--- a/backend/lib/CodeGen/MachineCSE.cpp
+++ b/backend/lib/CodeGen/MachineCSE.cpp
@@ -7,7 +7,6 @@
 #include "rcc/CodeGen/MachineAnalyses.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineMemOperand.h"
 #include "rcc/CodeGen/MachineOperand.h"
@@ -16,7 +15,6 @@
 
 #include <cstddef>
 #include <cstdint>
-#include <optional>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
@@ -293,24 +291,7 @@ const MachinePassContract &MachineCSEPass::contract() const noexcept {
 Expected<MachinePassResult> MachineCSEPass::run(MachineFunction &Function,
                                                 const TargetDescription &Target,
                                                 MachineFunctionAnalysisManager &Analyses) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "machine CSE transaction setup failed: "));
-  }
-  MachineFunctionAnalysisManager TrialAnalyses;
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target, TrialAnalyses);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-
-  auto Result = runImplementation(Function, Target, Analyses);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "machine CSE diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target, Analyses);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachineCombiner.cpp b/backend/lib/CodeGen/MachineCombiner.cpp
index 55bdc00..4c2ff88 100644
--- a/backend/lib/CodeGen/MachineCombiner.cpp
+++ b/backend/lib/CodeGen/MachineCombiner.cpp
@@ -4,7 +4,6 @@
 
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineIRBuilder.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineOperand.h"
@@ -13,7 +12,6 @@
 
 #include <cstddef>
 #include <cstdint>
-#include <optional>
 #include <string>
 
 namespace rcc {
@@ -204,32 +202,12 @@ const MachinePassContract &MachineCombinerPass::contract() const noexcept {
 Expected<MachinePassResult> MachineCombinerPass::run(MachineFunction &Function,
                                                      const TargetDescription &Target,
                                                      MachineFunctionAnalysisManager &Analyses) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "machine combiner transaction setup failed: "));
-  }
-  MachineActionReplay Actions(Analyses, Trial->InstructionStableIDs);
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target, Actions);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-  Actions.beginReplay();
-  auto Result = runImplementation(Function, Target, Actions);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "machine combiner diverged after a successful transaction preflight: "));
-  }
-  auto Replayed = Actions.finishReplay();
-  if (!Replayed)
-    return std::unexpected(Replayed.error());
-  return Result;
+  return runImplementation(Function, Target, Analyses);
 }
 
 Expected<MachinePassResult>
 MachineCombinerPass::runImplementation(MachineFunction &Function, const TargetDescription &Target,
-                                       MachineActionReplay &Actions) const {
+                                       MachineFunctionAnalysisManager &Analyses) const {
   if (Options.MaximumIterations == 0)
     return makeUnexpected(ErrorCode::InvalidArgument,
                           "machine combiner iteration budget must be nonzero");
@@ -251,7 +229,7 @@ MachineCombinerPass::runImplementation(MachineFunction &Function, const TargetDe
             continue;
           std::string Rule = "combine.";
           Rule.append(Pattern.Name);
-          auto Accepted = Actions.request(Rule, Function, Instruction->stableID());
+          auto Accepted = Analyses.requestAction(Rule, Function, Instruction->stableID());
           if (!Accepted)
             return std::unexpected(Accepted.error());
           if (!*Accepted)
diff --git a/backend/lib/CodeGen/MachineCopyPropagation.cpp b/backend/lib/CodeGen/MachineCopyPropagation.cpp
index f5736b8..9cb64cb 100644
--- a/backend/lib/CodeGen/MachineCopyPropagation.cpp
+++ b/backend/lib/CodeGen/MachineCopyPropagation.cpp
@@ -6,7 +6,6 @@
 #include "rcc/CodeGen/InstructionDescriptor.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineOperand.h"
 #include "rcc/CodeGen/RegisterMask.h"
@@ -303,33 +302,13 @@ const MachinePassContract &MachineCopyPropagationPass::contract() const noexcept
 Expected<MachinePassResult>
 MachineCopyPropagationPass::run(MachineFunction &Function, const TargetDescription &Target,
                                 MachineFunctionAnalysisManager &Analyses) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "COPY propagation transaction setup failed: "));
-  }
-  MachineActionReplay Actions(Analyses, Trial->InstructionStableIDs);
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target, Actions);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-  Actions.beginReplay();
-  auto Result = runImplementation(Function, Target, Actions);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "COPY propagation diverged after a successful transaction preflight: "));
-  }
-  auto Replayed = Actions.finishReplay();
-  if (!Replayed)
-    return std::unexpected(Replayed.error());
-  return Result;
+  return runImplementation(Function, Target, Analyses);
 }
 
 Expected<MachinePassResult>
 MachineCopyPropagationPass::runImplementation(MachineFunction &Function,
                                               const TargetDescription &Target,
-                                              MachineActionReplay &Actions) const {
+                                              MachineFunctionAnalysisManager &Analyses) const {
   MachinePassResult Result;
   std::size_t PropagatedCopies = 0;
   for (MachineBasicBlock *Block = Function.firstBlock(); Block != nullptr; Block = Block->next()) {
@@ -347,7 +326,8 @@ MachineCopyPropagationPass::runImplementation(MachineFunction &Function,
         Instruction = Next;
         continue;
       }
-      auto Accepted = Actions.request("propagate-copy", Function, Instruction->stableID());
+      auto Accepted =
+          Analyses.requestAction("propagate-copy", Function, Instruction->stableID());
       if (!Accepted)
         return std::unexpected(Accepted.error());
       if (!*Accepted) {
diff --git a/backend/lib/CodeGen/MachineDCE.cpp b/backend/lib/CodeGen/MachineDCE.cpp
index 6681bc1..269999b 100644
--- a/backend/lib/CodeGen/MachineDCE.cpp
+++ b/backend/lib/CodeGen/MachineDCE.cpp
@@ -6,7 +6,6 @@
 #include "rcc/CodeGen/LiveVariables.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineOperand.h"
 #include "rcc/CodeGen/MachineRegisterInfo.h"
@@ -111,23 +110,7 @@ const MachinePassContract &MachineDCEPass::contract() const noexcept {
 Expected<MachinePassResult> MachineDCEPass::run(MachineFunction &Function,
                                                 const TargetDescription &Target,
                                                 MachineFunctionAnalysisManager &) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "machine DCE transaction setup failed: "));
-  }
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-
-  auto Result = runImplementation(Function, Target);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "machine DCE diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target);
 }
 
 Expected<MachinePassResult> MachineDCEPass::runImplementation(MachineFunction &Function,
diff --git a/backend/lib/CodeGen/MachineLICM.cpp b/backend/lib/CodeGen/MachineLICM.cpp
index 6d76d5d..6ab15dc 100644
--- a/backend/lib/CodeGen/MachineLICM.cpp
+++ b/backend/lib/CodeGen/MachineLICM.cpp
@@ -7,7 +7,6 @@
 #include "rcc/CodeGen/MachineAnalyses.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineOperand.h"
 #include "rcc/CodeGen/MachineRegisterInfo.h"
@@ -321,24 +320,7 @@ const MachinePassContract &MachineLICMPass::contract() const noexcept {
 Expected<MachinePassResult> MachineLICMPass::run(MachineFunction &Function,
                                                  const TargetDescription &Target,
                                                  MachineFunctionAnalysisManager &Analyses) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "machine LICM transaction setup failed: "));
-  }
-  MachineFunctionAnalysisManager TrialAnalyses;
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target, TrialAnalyses);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-
-  auto Result = runImplementation(Function, Target, Analyses);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "machine LICM diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target, Analyses);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachineMemoryFolding.cpp b/backend/lib/CodeGen/MachineMemoryFolding.cpp
index 388f72c..fb4b86d 100644
--- a/backend/lib/CodeGen/MachineMemoryFolding.cpp
+++ b/backend/lib/CodeGen/MachineMemoryFolding.cpp
@@ -5,7 +5,6 @@
 #include "rcc/CodeGen/InstructionDescriptor.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineMemOperand.h"
 #include "rcc/CodeGen/MachineOperand.h"
@@ -181,22 +180,7 @@ const MachinePassContract &MachineMemoryFoldingPass::contract() const noexcept {
 Expected<MachinePassResult> MachineMemoryFoldingPass::run(MachineFunction &Function,
                                                           const TargetDescription &Target,
                                                           MachineFunctionAnalysisManager &) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "memory folding transaction setup failed: "));
-  }
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-  auto Result = runImplementation(Function, Target);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "memory folding diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachinePeepholeOptimizer.cpp b/backend/lib/CodeGen/MachinePeepholeOptimizer.cpp
index 16c935d..ae39334 100644
--- a/backend/lib/CodeGen/MachinePeepholeOptimizer.cpp
+++ b/backend/lib/CodeGen/MachinePeepholeOptimizer.cpp
@@ -4,13 +4,10 @@
 
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/TargetDescription.h"
 #include "rcc/CodeGen/TargetInstrInfo.h"
 
-#include <optional>
-
 namespace rcc {
 namespace {
 
@@ -41,23 +38,7 @@ const MachinePassContract &MachinePeepholeOptimizerPass::contract() const noexce
 Expected<MachinePassResult> MachinePeepholeOptimizerPass::run(MachineFunction &Function,
                                                               const TargetDescription &Target,
                                                               MachineFunctionAnalysisManager &) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "machine peephole transaction setup failed: "));
-  }
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-
-  auto Result = runImplementation(Function, Target);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "machine peephole diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachineSink.cpp b/backend/lib/CodeGen/MachineSink.cpp
index 1c2d2b7..dda2048 100644
--- a/backend/lib/CodeGen/MachineSink.cpp
+++ b/backend/lib/CodeGen/MachineSink.cpp
@@ -7,7 +7,6 @@
 #include "rcc/CodeGen/MachineAnalyses.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineOperand.h"
 #include "rcc/CodeGen/MachineRegisterInfo.h"
@@ -343,24 +342,7 @@ const MachinePassContract &MachineSinkPass::contract() const noexcept {
 Expected<MachinePassResult> MachineSinkPass::run(MachineFunction &Function,
                                                  const TargetDescription &Target,
                                                  MachineFunctionAnalysisManager &Analyses) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "machine sink transaction setup failed: "));
-  }
-  MachineFunctionAnalysisManager TrialAnalyses;
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target, TrialAnalyses);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-
-  auto Result = runImplementation(Function, Target, Analyses);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "machine sink diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target, Analyses);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachineStackSlotColoring.cpp b/backend/lib/CodeGen/MachineStackSlotColoring.cpp
index eef913f..1717a20 100644
--- a/backend/lib/CodeGen/MachineStackSlotColoring.cpp
+++ b/backend/lib/CodeGen/MachineStackSlotColoring.cpp
@@ -5,7 +5,6 @@
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFrameInfo.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineMemOperand.h"
 #include "rcc/CodeGen/MachineOperand.h"
@@ -221,28 +220,13 @@ const MachinePassContract &MachineStackSlotColoringPass::contract() const noexce
 }
 
 Expected<MachinePassResult> MachineStackSlotColoringPass::run(MachineFunction &Function,
-                                                              const TargetDescription &Target,
+                                                              const TargetDescription &,
                                                               MachineFunctionAnalysisManager &) {
   if (Function.frameInfo().isFrozen()) {
     return makeUnexpected(ErrorCode::FrameLayoutFailed,
                           "stack-slot coloring must run before frame layout is frozen");
   }
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "stack-slot coloring transaction setup failed: "));
-  }
-  auto TrialResult = runImplementation(*Trial->ClonedFunction);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-  auto Result = runImplementation(Function);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "stack-slot coloring diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function);
 }
 
 Expected<MachinePassResult>
diff --git a/backend/lib/CodeGen/MachineTailDuplication.cpp b/backend/lib/CodeGen/MachineTailDuplication.cpp
index 3478400..53c67c6 100644
--- a/backend/lib/CodeGen/MachineTailDuplication.cpp
+++ b/backend/lib/CodeGen/MachineTailDuplication.cpp
@@ -8,7 +8,6 @@
 #include "rcc/CodeGen/MachineBasicBlockAttributes.h"
 #include "rcc/CodeGen/MachineCFGUpdater.h"
 #include "rcc/CodeGen/MachineFunction.h"
-#include "rcc/CodeGen/MachineFunctionCloner.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineJumpTableInfo.h"
 #include "rcc/CodeGen/MachineMemOperand.h"
@@ -240,22 +239,7 @@ const MachinePassContract &MachineTailDuplicationPass::contract() const noexcept
 Expected<MachinePassResult> MachineTailDuplicationPass::run(MachineFunction &Function,
                                                             const TargetDescription &Target,
                                                             MachineFunctionAnalysisManager &) {
-  auto Trial = cloneMachineFunction(
-      Function, Target,
-      MachineFunctionCloneOptions{.NewStableID = Function.stableID(), .NewName = std::nullopt});
-  if (!Trial) {
-    return std::unexpected(
-        withErrorContext(Trial.error(), "tail duplication transaction setup failed: "));
-  }
-  auto TrialResult = runImplementation(*Trial->ClonedFunction, Target);
-  if (!TrialResult)
-    return std::unexpected(TrialResult.error());
-  auto Result = runImplementation(Function, Target);
-  if (!Result) {
-    return std::unexpected(withErrorContext(
-        Result.error(), "tail duplication diverged after a successful transaction preflight: "));
-  }
-  return Result;
+  return runImplementation(Function, Target);
 }
 
 Expected<MachinePassResult>