Merge pull request #82320 from xedin/hide-solver-hacks-behind-a-flag

[ConstraintSystem] Guard all the performance hacks with a flag

include/swift/Basic/LangOptions.h

@@ -983,9 +983,6 @@ namespace swift {
     /// is for testing purposes.
     std::vector<std::string> DebugForbidTypecheckPrefixes;
 
-    /// Disable the shrink phase of the expression type checker.
-    bool SolverDisableShrink = false;
-
     /// Enable experimental operator designated types feature.
     bool EnableOperatorDesignatedTypes = false;
 

include/swift/Option/FrontendOptions.td

@@ -856,10 +856,6 @@ def solver_scope_threshold_EQ : Joined<["-"], "solver-scope-threshold=">,
 def solver_trail_threshold_EQ : Joined<["-"], "solver-trail-threshold=">,
   HelpText<"Expression type checking trail change limit">;
 
-def solver_disable_shrink :
-  Flag<["-"], "solver-disable-shrink">,
-  HelpText<"Disable the shrink phase of expression type checking">;
-
 def solver_disable_splitter : Flag<["-"], "solver-disable-splitter">,
   HelpText<"Disable the component splitter phase of expression type checking">;
 

include/swift/Sema/ConstraintSystem.h

@@ -3586,6 +3586,13 @@ public:
     return Options.contains(ConstraintSystemFlags::ForCodeCompletion);
   }
 
+  /// Check whether type-checker performance hacks has been explicitly
+  /// disabled by a flag.
+  bool performanceHacksEnabled() const {
+    return !getASTContext()
+                .TypeCheckerOpts.DisableConstraintSolverPerformanceHacks;
+  }
+
   /// Log and record the application of the fix. Return true iff any
   /// subsequent solution would be worse than the best known solution.
   bool recordFix(ConstraintFix *fix, unsigned impact = 1);