x87: Use signaling NaN for holes in fixed double arrays.

src/x87/lithium-codegen-x87.cc

 // Copyright 2012 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/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 1983 matching lines @@
   __ Move(ToRegister(instr->result()), Immediate(instr->value()));
 }
 
 
 void LCodeGen::DoConstantS(LConstantS* instr) {
   __ Move(ToRegister(instr->result()), Immediate(instr->value()));
 }
 
 
 void LCodeGen::DoConstantD(LConstantD* instr) {
-  double v = instr->value();
-  uint64_t int_val = bit_cast<uint64_t, double>(v);
-  int32_t lower = static_cast<int32_t>(int_val);
-  int32_t upper = static_cast<int32_t>(int_val >> (kBitsPerInt));
+  uint64_t const bits = instr->bits();
+  uint32_t const lower = static_cast<uint32_t>(bits);
+  uint32_t const upper = static_cast<uint32_t>(bits >> 32);
   DCHECK(instr->result()->IsDoubleRegister());
 
   __ push(Immediate(upper));
   __ push(Immediate(lower));
   X87Register reg = ToX87Register(instr->result());
   X87Mov(reg, Operand(esp, 0));
   __ add(Operand(esp), Immediate(kDoubleSize));
 }
 
 
@@ skipping 588 matching lines @@
   __ fstp(0);
   EmitFalseBranch(instr, no_condition);
   __ bind(&ok);
 
 
   __ sub(esp, Immediate(kDoubleSize));
   __ fstp_d(MemOperand(esp, 0));
 
   __ add(esp, Immediate(kDoubleSize));
   int offset = sizeof(kHoleNanUpper32);
-  __ cmp(MemOperand(esp, -offset), Immediate(kHoleNanUpper32));
+  // x87 converts sNaN(0xfff7fffffff7ffff) to QNaN(0xfffffffffff7ffff),
+  // so we check the upper with 0xffffffff for hole as a temporary fix.
+  __ cmp(MemOperand(esp, -offset), Immediate(0xffffffff));
   EmitBranch(instr, equal);
 }
 
 
 void LCodeGen::DoCompareMinusZeroAndBranch(LCompareMinusZeroAndBranch* instr) {
   Representation rep = instr->hydrogen()->value()->representation();
   DCHECK(!rep.IsInteger32());
 
   if (rep.IsDouble()) {
     X87Register input = ToX87Register(instr->value());
@@ skipping 1608 matching lines @@
   // Positive input.
   // {input, ln2}.
   __ fldln2();
   // {ln2, input}.
   __ fxch();
   // {result}.
   __ fyl2x();
   __ jmp(&done, Label::kNear);
 
   __ bind(&nan_result);
-  ExternalReference nan =
-      ExternalReference::address_of_canonical_non_hole_nan();
   X87PrepareToWrite(input_reg);
-  __ fld_d(Operand::StaticVariable(nan));
+  __ push(Immediate(0xffffffff));
+  __ push(Immediate(0x7fffffff));
+  __ fld_d(MemOperand(esp, 0));
+  __ lea(esp, Operand(esp, kDoubleSize));
   X87CommitWrite(input_reg);
   __ jmp(&done, Label::kNear);
 
   __ bind(&zero);
   ExternalReference ninf = ExternalReference::address_of_negative_infinity();
   X87PrepareToWrite(input_reg);
   __ fld_d(Operand::StaticVariable(ninf));
   X87CommitWrite(input_reg);
 
   __ bind(&done);
@@ skipping 374 matching lines @@
       case DICTIONARY_ELEMENTS:
       case SLOPPY_ARGUMENTS_ELEMENTS:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoStoreKeyedFixedDoubleArray(LStoreKeyed* instr) {
-  ExternalReference canonical_nan_reference =
-      ExternalReference::address_of_canonical_non_hole_nan();
   Operand double_store_operand = BuildFastArrayOperand(
       instr->elements(),
       instr->key(),
       instr->hydrogen()->key()->representation(),
       FAST_DOUBLE_ELEMENTS,
       instr->base_offset());
 
-  // Can't use SSE2 in the serializer
+  uint64_t int_val = kHoleNanInt64;
+  int32_t lower = static_cast<int32_t>(int_val);
+  int32_t upper = static_cast<int32_t>(int_val >> (kBitsPerInt));
+  Operand double_store_operand2 = BuildFastArrayOperand(
+      instr->elements(), instr->key(),
+      instr->hydrogen()->key()->representation(), FAST_DOUBLE_ELEMENTS,
+      instr->base_offset() + kPointerSize);
+
   if (instr->hydrogen()->IsConstantHoleStore()) {
     // This means we should store the (double) hole. No floating point
     // registers required.
-    double nan_double = FixedDoubleArray::hole_nan_as_double();
-    uint64_t int_val = bit_cast<uint64_t, double>(nan_double);
-    int32_t lower = static_cast<int32_t>(int_val);
-    int32_t upper = static_cast<int32_t>(int_val >> (kBitsPerInt));
-
     __ mov(double_store_operand, Immediate(lower));
-    Operand double_store_operand2 = BuildFastArrayOperand(
-        instr->elements(),
-        instr->key(),
-        instr->hydrogen()->key()->representation(),
-        FAST_DOUBLE_ELEMENTS,
-        instr->base_offset() + kPointerSize);
     __ mov(double_store_operand2, Immediate(upper));
   } else {
-    Label no_special_nan_handling;
+    Label no_special_nan_handling, done;
     X87Register value = ToX87Register(instr->value());
     X87Fxch(value);
 
     if (instr->NeedsCanonicalization()) {
       __ fld(0);
       __ fld(0);
       __ FCmp();
-
       __ j(parity_odd, &no_special_nan_handling, Label::kNear);
-      __ sub(esp, Immediate(kDoubleSize));
+      // All NaNs are Canonicalized to 0x7fffffffffffffff
+      __ mov(double_store_operand, Immediate(0xffffffff));
+      __ mov(double_store_operand2, Immediate(0x7fffffff));
+      __ jmp(&done, Label::kNear);
+    } else {
+      __ lea(esp, Operand(esp, -kDoubleSize));
       __ fst_d(MemOperand(esp, 0));
-      __ cmp(MemOperand(esp, sizeof(kHoleNanLower32)),
-             Immediate(kHoleNanUpper32));
-      __ add(esp, Immediate(kDoubleSize));
-      Label canonicalize;
-      __ j(not_equal, &canonicalize, Label::kNear);
-      __ jmp(&no_special_nan_handling, Label::kNear);
-      __ bind(&canonicalize);
-      __ fstp(0);
-      __ fld_d(Operand::StaticVariable(canonical_nan_reference));
+      __ lea(esp, Operand(esp, kDoubleSize));
+      int offset = sizeof(kHoleNanUpper32);
+      // x87 converts sNaN(0xfff7fffffff7ffff) to QNaN(0xfffffffffff7ffff),
+      // so we check the upper with 0xffffffff for hole as a temporary fix.
+      __ cmp(MemOperand(esp, -offset), Immediate(0xffffffff));
+      __ j(not_equal, &no_special_nan_handling, Label::kNear);
+      __ mov(double_store_operand, Immediate(lower));
+      __ mov(double_store_operand2, Immediate(upper));
+      __ jmp(&done, Label::kNear);
     }
-
     __ bind(&no_special_nan_handling);
     __ fst_d(double_store_operand);
+    __ bind(&done);
   }
 }
 
 
 void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
   Register elements = ToRegister(instr->elements());
   Register key = instr->key()->IsRegister() ? ToRegister(instr->key()) : no_reg;
 
   Operand operand = BuildFastArrayOperand(
       instr->elements(),
@@ skipping 477 matching lines @@
       DeoptimizeIf(not_equal, instr, "not a heap number");
     } else {
       Label heap_number, convert;
       __ j(equal, &heap_number);
 
       // Convert undefined (or hole) to NaN.
       __ cmp(input_reg, factory()->undefined_value());
       DeoptimizeIf(not_equal, instr, "not a heap number/undefined");
 
       __ bind(&convert);
-      ExternalReference nan =
-          ExternalReference::address_of_canonical_non_hole_nan();
-      __ fld_d(Operand::StaticVariable(nan));
+      __ push(Immediate(0xffffffff));
+      __ push(Immediate(0x7fffffff));
+      __ fld_d(MemOperand(esp, 0));
+      __ lea(esp, Operand(esp, kDoubleSize));
       __ jmp(&done, Label::kNear);
 
       __ bind(&heap_number);
     }
     // Heap number to x87 conversion.
     __ fld_d(FieldOperand(input_reg, HeapNumber::kValueOffset));
     if (deoptimize_on_minus_zero) {
       __ fldz();
       __ FCmp();
       __ fld_d(FieldOperand(input_reg, HeapNumber::kValueOffset));
@@ skipping 1125 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X87