[Frontend] Remove -disable-solver-shrink option

It's folded into a more general "disable performance hacks" one.

Author: xedin

include/swift/Basic/LangOptions.h

@@ -975,9 +975,6 @@ 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

@@ -852,10 +852,6 @@ 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">;
 

lib/Frontend/CompilerInvocation.cpp

@@ -2015,9 +2015,6 @@ static bool ParseTypeCheckerArgs(TypeCheckerOptions &Opts, ArgList &Args,
     Opts.DebugForbidTypecheckPrefixes.push_back(A);
   }
 
-  if (Args.getLastArg(OPT_solver_disable_shrink))
-    Opts.SolverDisableShrink = true;
-
   if (Args.getLastArg(OPT_solver_disable_splitter))
     Opts.SolverDisableSplitter = true;
 

lib/Sema/CSSolver.cpp

@@ -983,7 +983,7 @@ void ConstraintSystem::Candidate::applySolutions(
 }
 
 void ConstraintSystem::shrink(Expr *expr) {
-  if (getASTContext().TypeCheckerOpts.SolverDisableShrink)
+  if (getASTContext().TypeCheckerOpts.DisableConstraintSolverPerformanceHacks)
     return;
 
   using DomainMap = llvm::SmallDenseMap<Expr *, ArrayRef<ValueDecl *>>;

validation-test/Sema/type_checker_perf/fast/array_concatenation.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-disable-shrink
+// RUN: %target-typecheck-verify-swift -disable-constraint-solver-performance-hacks
 
 // Self-contained test case
 protocol P1 {}; func f<T: P1>(_: T, _: T) -> T { fatalError() }

validation-test/Sema/type_checker_perf/fast/property_vs_unapplied_func.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1 -solver-disable-shrink
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1
 // REQUIRES: tools-release,no_asan
 
 struct Date {

validation-test/Sema/type_checker_perf/slow/rdar26564101.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1 -solver-disable-shrink
+// RUN: %target-typecheck-verify-swift -solver-expression-time-threshold=1 -disable-constraint-solver-performance-hacks
 // REQUIRES: tools-release,no_asan
 // UNSUPPORTED: swift_test_mode_optimize_none && OS=linux-gnu