Fix the hole loading optimization.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4645 matching lines @@
 
 
 void LCodeGen::EmitNumberUntagD(Register input_reg,
                                 XMMRegister result_reg,
                                 bool deoptimize_on_undefined,
                                 bool deoptimize_on_minus_zero,
                                 LEnvironment* env,
                                 NumberUntagDMode mode) {
   Label load_smi, done;
 
-  if (mode == NUMBER_CANDIDATE_IS_ANY_TAGGED) {
+  STATIC_ASSERT(NUMBER_CANDIDATE_IS_ANY_TAGGED_CONVERT_HOLE >
+                NUMBER_CANDIDATE_IS_ANY_TAGGED);
+  if (mode >= NUMBER_CANDIDATE_IS_ANY_TAGGED) {
     // Smi check.
     __ JumpIfSmi(input_reg, &load_smi, Label::kNear);
 
     // Heap number map check.
     __ CompareRoot(FieldOperand(input_reg, HeapObject::kMapOffset),
                    Heap::kHeapNumberMapRootIndex);
     if (deoptimize_on_undefined) {
       DeoptimizeIf(not_equal, env);
     } else {
-      Label heap_number;
+      Label heap_number, convert;
       __ j(equal, &heap_number, Label::kNear);
 
+      // Convert undefined (and hole) to NaN. Compute NaN as 0/0.
       __ CompareRoot(input_reg, Heap::kUndefinedValueRootIndex);
+      if (mode == NUMBER_CANDIDATE_IS_ANY_TAGGED_CONVERT_HOLE) {
+        __ j(equal, &convert, Label::kNear);
+        __ CompareRoot(input_reg, Heap::kTheHoleValueRootIndex);
+      }
       DeoptimizeIf(not_equal, env);
 
-      // Convert undefined to NaN. Compute NaN as 0/0.
+      __ bind(&convert);
       __ xorps(result_reg, result_reg);
       __ divsd(result_reg, result_reg);
       __ jmp(&done, Label::kNear);
 
       __ bind(&heap_number);
     }
     // Heap number to XMM conversion.
     __ movsd(result_reg, FieldOperand(input_reg, HeapNumber::kValueOffset));
     if (deoptimize_on_minus_zero) {
       XMMRegister xmm_scratch = xmm0;
       __ xorps(xmm_scratch, xmm_scratch);
       __ ucomisd(xmm_scratch, result_reg);
       __ j(not_equal, &done, Label::kNear);
       __ movmskpd(kScratchRegister, result_reg);
       __ testq(kScratchRegister, Immediate(1));
       DeoptimizeIf(not_zero, env);
     }
     __ jmp(&done, Label::kNear);
-  } else if (mode == NUMBER_CANDIDATE_IS_SMI_OR_HOLE) {
-      __ testq(input_reg, Immediate(kSmiTagMask));
-      DeoptimizeIf(not_equal, env);
-  } else if (mode == NUMBER_CANDIDATE_IS_SMI_CONVERT_HOLE) {
-      __ testq(input_reg, Immediate(kSmiTagMask));
-      __ j(zero, &load_smi);
-    __ Set(kScratchRegister, BitCast<uint64_t>(
-        FixedDoubleArray::hole_nan_as_double()));
-    __ movq(result_reg, kScratchRegister);
-      __ jmp(&done, Label::kNear);
   } else {
     ASSERT(mode == NUMBER_CANDIDATE_IS_SMI);
   }
 
   // Smi to XMM conversion
   __ bind(&load_smi);
   __ SmiToInteger32(kScratchRegister, input_reg);
   __ cvtlsi2sd(result_reg, kScratchRegister);
   __ bind(&done);
 }
@@ skipping 74 matching lines @@
   ASSERT(input->IsRegister());
   LOperand* result = instr->result();
   ASSERT(result->IsDoubleRegister());
 
   Register input_reg = ToRegister(input);
   XMMRegister result_reg = ToDoubleRegister(result);
 
   NumberUntagDMode mode = NUMBER_CANDIDATE_IS_ANY_TAGGED;
   HValue* value = instr->hydrogen()->value();
   if (value->type().IsSmi()) {
-    if (value->IsLoadKeyed()) {
-      HLoadKeyed* load = HLoadKeyed::cast(value);
-      if (load->UsesMustHandleHole()) {
-        if (load->hole_mode() == ALLOW_RETURN_HOLE) {
-          mode = NUMBER_CANDIDATE_IS_SMI_CONVERT_HOLE;
-        } else {
-          mode = NUMBER_CANDIDATE_IS_SMI_OR_HOLE;
-        }
-      } else {
-        mode = NUMBER_CANDIDATE_IS_SMI;
-      }
-    } else {
-      mode = NUMBER_CANDIDATE_IS_SMI;
+    mode = NUMBER_CANDIDATE_IS_SMI;
+  } else if (value->IsLoadKeyed()) {
+    HLoadKeyed* load = HLoadKeyed::cast(value);
+    if (load->UsesMustHandleHole()) {
+      mode = NUMBER_CANDIDATE_IS_ANY_TAGGED_CONVERT_HOLE;
     }
   }
 
   EmitNumberUntagD(input_reg, result_reg,
                    instr->hydrogen()->deoptimize_on_undefined(),
                    instr->hydrogen()->deoptimize_on_minus_zero(),
                    instr->environment(),
                    mode);
 }
 
@@ skipping 845 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64