[Turbofan] Simplify operand canonicalization on archs with simple FP aliasing.

src/compiler/instruction.h

 // 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.
 
 #ifndef V8_COMPILER_INSTRUCTION_H_
 #define V8_COMPILER_INSTRUCTION_H_
 
 #include <deque>
 #include <iosfwd>
 #include <map>
@@ skipping 588 matching lines @@
   return (IsAllocated() || IsExplicit()) &&
          LocationOperand::cast(this)->location_kind() ==
              LocationOperand::STACK_SLOT &&
          LocationOperand::cast(this)->representation() ==
              MachineRepresentation::kSimd128;
 }
 
 uint64_t InstructionOperand::GetCanonicalizedValue() const {
   if (IsAllocated() || IsExplicit()) {
     MachineRepresentation rep = LocationOperand::cast(this)->representation();
-    // Preserve FP representation so we can check for interference on
-    // architectures with complex register aliasing.
-    MachineRepresentation canonical =
-        IsFPRegister() ? rep : MachineRepresentation::kNone;
+    MachineRepresentation canonical = MachineRepresentation::kNone;
+    if (IsFloatingPoint(rep)) {
+      if (kSimpleFPAliasing) {
+        // Archs with simple aliasing can treat all FP operands the same.
+        canonical = MachineRepresentation::kFloat64;
+      } else {
+        // We need to distinguish FP operands of different reps when FP
+        // aliasing is not simple (e.g. ARM).
+        canonical = rep;
+      }
+    }
     return InstructionOperand::KindField::update(
         LocationOperand::RepresentationField::update(this->value_, canonical),
         LocationOperand::EXPLICIT);
   }
   return this->value_;
 }
 
-
 // Required for maps that don't care about machine type.
 struct CompareOperandModuloType {
   bool operator()(const InstructionOperand& a,
                   const InstructionOperand& b) const {
     return a.CompareCanonicalized(b);
   }
 };
 
 
 class MoveOperands final : public ZoneObject {
@@ skipping 850 matching lines @@
 
 
 std::ostream& operator<<(std::ostream& os,
                          const PrintableInstructionSequence& code);
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_H_