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

- Changes InstructionOperand canonicalization to map all FP operands to kFloat64 on Intel and other platforms with simple aliasing.
- Bypass expensive interference calculations and fixed FP live range processing for platforms with simple aliasing.

LOG=N
BUG=v8:4124

Review-Url: https://codereview.chromium.org/2101653003
Cr-Commit-Position: refs/heads/master@{#37388}

src/compiler/instruction.cc

@@ -61,16 +61,14 @@ FlagsCondition CommuteFlagsCondition(FlagsCondition condition) {
 }
 
 bool InstructionOperand::InterferesWith(const InstructionOperand& that) const {
-  if (!IsFPRegister() || !that.IsFPRegister()) return EqualsCanonicalized(that);
-
+  if (!IsFPRegister() || !that.IsFPRegister() || kSimpleFPAliasing)
+    return EqualsCanonicalized(that);
+  // Both operands are fp registers and aliasing is non-simple.
   const LocationOperand& loc1 = *LocationOperand::cast(this);
   const LocationOperand& loc2 = LocationOperand::cast(that);
-  const RegisterConfiguration* config = GetRegConfig();
-  if (config->fp_aliasing_kind() != RegisterConfiguration::COMBINE)
-    return loc1.register_code() == loc2.register_code();
-
-  return config->AreAliases(loc1.representation(), loc1.register_code(),
-                            loc2.representation(), loc2.register_code());
+  return GetRegConfig()->AreAliases(loc1.representation(), loc1.register_code(),
+                                    loc2.representation(),
+                                    loc2.register_code());
 }
 
 void InstructionOperand::Print(const RegisterConfiguration* config) const {

src/compiler/instruction.h

@@ -606,10 +606,17 @@ bool InstructionOperand::IsSimd128StackSlot() const {
 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);
@@ -617,7 +624,6 @@ uint64_t InstructionOperand::GetCanonicalizedValue() const {
   return this->value_;
 }
 
-
 // Required for maps that don't care about machine type.
 struct CompareOperandModuloType {
   bool operator()(const InstructionOperand& a,

src/compiler/move-optimizer.cc

@@ -29,8 +29,8 @@ typedef ZoneSet<InstructionOperand, CompareOperandModuloType> OperandSet;
 
 bool Blocks(const OperandSet& set, const InstructionOperand& operand) {
   if (set.find(operand) != set.end()) return true;
-  // Only FP registers alias.
-  if (!operand.IsFPRegister()) return false;
+  // Only FP registers on archs with non-simple aliasing need extra checks.
+  if (!operand.IsFPRegister() || kSimpleFPAliasing) return false;
 
   const LocationOperand& loc = LocationOperand::cast(operand);
   MachineRepresentation rep = loc.representation();

src/compiler/register-allocator.cc

@@ -2070,6 +2070,8 @@ void LiveRangeBuilder::ProcessInstructions(const InstructionBlock* block,
                                 allocation_zone());
         }
       }
+      // Preserve fixed float registers on archs with non-simple aliasing.
+      if (!kSimpleFPAliasing) {
         for (int i = 0; i < config()->num_allocatable_float_registers(); ++i) {
           int code = config()->GetAllocatableFloatCode(i);
           if (!IsOutputFPRegisterOf(instr, MachineRepresentation::kFloat32,
@@ -2081,6 +2083,7 @@ void LiveRangeBuilder::ProcessInstructions(const InstructionBlock* block,
           }
         }
       }
+    }
 
     for (size_t i = 0; i < instr->InputCount(); i++) {
       InstructionOperand* input = instr->InputAt(i);