[Turbofan] Revert FP register aliasing support on Arm.

src/compiler/move-optimizer.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/move-optimizer.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 10 matching lines @@
       return a.destination.CompareCanonicalized(b.destination);
     }
     return a.source.CompareCanonicalized(b.source);
   }
 };
 
 typedef ZoneMap<MoveKey, unsigned, MoveKeyCompare> MoveMap;
 typedef ZoneSet<InstructionOperand, CompareOperandModuloType> OperandSet;
 
 bool Blocks(const OperandSet& set, const InstructionOperand& operand) {
-  if (set.find(operand) != set.end()) return true;
-  // Only FP registers on archs with non-simple aliasing need extra checks.
-  if (!operand.IsFPRegister() || kSimpleFPAliasing) return false;
+  if (!operand.IsFPRegister()) return set.find(operand) != set.end();
 
-  // Check operand against operands of other FP types for interference.
   const LocationOperand& loc = LocationOperand::cast(operand);
-  MachineRepresentation rep = loc.representation();
-  MachineRepresentation other_rep1, other_rep2;
-  switch (rep) {
-    case MachineRepresentation::kFloat32:
-      other_rep1 = MachineRepresentation::kFloat64;
-      other_rep2 = MachineRepresentation::kSimd128;
-      break;
-    case MachineRepresentation::kFloat64:
-      other_rep1 = MachineRepresentation::kFloat32;
-      other_rep2 = MachineRepresentation::kSimd128;
-      break;
-    case MachineRepresentation::kSimd128:
-      other_rep1 = MachineRepresentation::kFloat32;
-      other_rep2 = MachineRepresentation::kFloat64;
-      break;
-    default:
-      UNREACHABLE();
-      break;
+  if (loc.representation() == MachineRepresentation::kFloat64) {
+    return set.find(operand) != set.end() ||
+           set.find(LocationOperand(loc.kind(), loc.location_kind(),
+                                    MachineRepresentation::kFloat32,
+                                    loc.register_code())) != set.end();
   }
-  const RegisterConfiguration* config = RegisterConfiguration::Turbofan();
-  int base = -1;
-  int aliases = config->GetAliases(rep, loc.register_code(), other_rep1, &base);
-  DCHECK(aliases > 0 || (aliases == 0 && base == -1));
-  while (aliases--) {
-    if (set.find(LocationOperand(loc.kind(), loc.location_kind(), other_rep1,
-                                 base + aliases)) != set.end())
-      return true;
-  }
-  aliases = config->GetAliases(rep, loc.register_code(), other_rep2, &base);
-  DCHECK(aliases > 0 || (aliases == 0 && base == -1));
-  while (aliases--) {
-    if (set.find(LocationOperand(loc.kind(), loc.location_kind(), other_rep2,
-                                 base + aliases)) != set.end())
-      return true;
-  }
-  return false;
+  DCHECK_EQ(MachineRepresentation::kFloat32, loc.representation());
+  return set.find(operand) != set.end() ||
+         set.find(LocationOperand(loc.kind(), loc.location_kind(),
+                                  MachineRepresentation::kFloat64,
+                                  loc.register_code())) != set.end();
 }
 
 int FindFirstNonEmptySlot(const Instruction* instr) {
   int i = Instruction::FIRST_GAP_POSITION;
   for (; i <= Instruction::LAST_GAP_POSITION; i++) {
     ParallelMove* moves = instr->parallel_moves()[i];
     if (moves == nullptr) continue;
     for (MoveOperands* move : *moves) {
       if (!move->IsRedundant()) return i;
       move->Eliminate();
@@ skipping 432 matching lines @@
         static_cast<Instruction::GapPosition>(1), code_zone());
     slot_1->AddMove(group_begin->destination(), load->destination());
     load->Eliminate();
   }
   loads.clear();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8