[gn] Enable stricter build flags

src/compiler/gap-resolver.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/gap-resolver.h"
 
 #include <algorithm>
 #include <functional>
 #include <set>
 
@@ skipping 130 matching lines @@
   DCHECK(!move->IsRedundant());
 
   // Clear this move's destination to indicate a pending move.  The actual
   // destination is saved on the side.
   InstructionOperand source = move->source();
   DCHECK(!source.IsInvalid());  // Or else it will look eliminated.
   InstructionOperand destination = move->destination();
   move->SetPending();
 
   // We may need to split moves between FP locations differently.
-  bool is_fp_loc_move = !kSimpleFPAliasing && destination.IsFPLocationOperand();
+  const bool is_fp_loc_move =
+      !kSimpleFPAliasing && destination.IsFPLocationOperand();
 
   // Perform a depth-first traversal of the move graph to resolve dependencies.
   // Any unperformed, unpending move with a source the same as this one's
   // destination blocks this one so recursively perform all such moves.
   for (size_t i = 0; i < moves->size(); ++i) {
     auto other = (*moves)[i];
     if (other->IsEliminated()) continue;
     if (other->IsPending()) continue;
     if (other->source().InterferesWith(destination)) {
-      if (!kSimpleFPAliasing && is_fp_loc_move &&
+      if (is_fp_loc_move &&
           LocationOperand::cast(other->source()).representation() >
               split_rep_) {
         // 'other' must also be an FP location move. Break it into fragments
         // of the same size as 'move'. 'other' is set to one of the fragments,
         // and the rest are appended to 'moves'.
         other = Split(other, split_rep_, moves);
         // 'other' may not block destination now.
         if (!other->source().InterferesWith(destination)) continue;
       }
       // Though PerformMove can change any source operand in the move graph,
@@ skipping 34 matching lines @@
   }
 
   // Ensure source is a register or both are stack slots, to limit swap cases.
   if (source.IsStackSlot() || source.IsFPStackSlot()) {
     std::swap(source, destination);
   }
   assembler_->AssembleSwap(&source, &destination);
   move->Eliminate();
 
   // Update outstanding moves whose source may now have been moved.
-  if (!kSimpleFPAliasing && is_fp_loc_move) {
+  if (is_fp_loc_move) {
     // We may have to split larger moves.
     for (size_t i = 0; i < moves->size(); ++i) {
       auto other = (*moves)[i];
       if (other->IsEliminated()) continue;
       if (source.InterferesWith(other->source())) {
         if (LocationOperand::cast(other->source()).representation() >
             split_rep_) {
           other = Split(other, split_rep_, moves);
           if (!source.InterferesWith(other->source())) continue;
         }
@@ skipping 14 matching lines @@
         other->set_source(destination);
       } else if (destination.EqualsCanonicalized(other->source())) {
         other->set_source(source);
       }
     }
   }
 }
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8