Optimize KeyedStoreGeneric for Smi arrays.

src/ia32/macro-assembler-ia32.cc

 // Copyright 2011 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 388 matching lines @@
 void MacroAssembler::CheckFastSmiOnlyElements(Register map,
                                               Label* fail,
                                               Label::Distance distance) {
   STATIC_ASSERT(FAST_SMI_ONLY_ELEMENTS == 0);
   cmpb(FieldOperand(map, Map::kBitField2Offset),
        Map::kMaximumBitField2FastSmiOnlyElementValue);
   j(above, fail, distance);
 }
 
 
+void MacroAssembler::StoreNumberToDoubleElements(
+    Register maybe_number,
+    Register elements,
+    Register key,
+    Register scratch1,
+    XMMRegister scratch2,
+    Label* fail,
+    bool specialize_for_processor) {
+  Label smi_value, done, maybe_nan, not_nan, is_nan, have_double_value;
+  JumpIfSmi(maybe_number, &smi_value, Label::kNear);
+
+  CheckMap(maybe_number,
+           isolate()->factory()->heap_number_map(),
+           fail,
+           DONT_DO_SMI_CHECK);
+
+  // Double value, canonicalize NaN.
+  uint32_t offset = HeapNumber::kValueOffset + sizeof(kHoleNanLower32);
+  cmp(FieldOperand(maybe_number, offset),
+      Immediate(kNaNOrInfinityLowerBoundUpper32));
+  j(greater_equal, &maybe_nan, Label::kNear);
+
+  bind(&not_nan);
+  ExternalReference canonical_nan_reference =
+      ExternalReference::address_of_canonical_non_hole_nan();
+  if (CpuFeatures::IsSupported(SSE2) && specialize_for_processor) {
+    CpuFeatures::Scope use_sse2(SSE2);
+    movdbl(scratch2, FieldOperand(maybe_number, HeapNumber::kValueOffset));
+    bind(&have_double_value);
+    movdbl(FieldOperand(elements, key, times_4, FixedDoubleArray::kHeaderSize),
+              scratch2);

[Rico, 2011/09/27 12:57:53]

indention

[danno, 2011/09/27 16:14:57]

Done.

+  } else {
+    fld_d(FieldOperand(maybe_number, HeapNumber::kValueOffset));
+    bind(&have_double_value);
+    fstp_d(FieldOperand(elements, key, times_4, FixedDoubleArray::kHeaderSize));
+  }
+  jmp(&done);
+
+  bind(&maybe_nan);
+  // Could be NaN or Infinity. If fraction is not zero, it's NaN, otherwise
+  // it's an Infinity, and the non-NaN code path applies.
+  j(greater, &is_nan, Label::kNear);
+  cmp(FieldOperand(maybe_number, HeapNumber::kValueOffset), Immediate(0));
+  j(zero, &not_nan);
+  bind(&is_nan);
+  if (CpuFeatures::IsSupported(SSE2) && specialize_for_processor) {
+    CpuFeatures::Scope use_sse2(SSE2);
+    movdbl(scratch2, Operand::StaticVariable(canonical_nan_reference));
+  } else {
+    fld_d(Operand::StaticVariable(canonical_nan_reference));
+  }
+  jmp(&have_double_value, Label::kNear);
+
+  bind(&smi_value);
+  // Value is a smi. convert to a double and store.

[Rico, 2011/09/27 12:57:53]

Capital c after period

[danno, 2011/09/27 16:14:57]

Done.

+  // Preserve original value.
+  mov(scratch1, maybe_number);
+  SmiUntag(scratch1);
+  push(scratch1);
+  fild_s(Operand(esp, 0));

[Rico, 2011/09/27 12:57:53]

Why not also use SSE2 instructions here if available, cvtsi2sd on scratch1 (no
need to push) and then store the loaded xmm register to the elements array.
Don't know it this makes a performance difference though

[danno, 2011/09/27 16:14:57]

Done.

+  pop(scratch1);
+  fstp_d(FieldOperand(elements, key, times_4, FixedDoubleArray::kHeaderSize));
+  bind(&done);
+}
+
+
 void MacroAssembler::CheckMap(Register obj,
                               Handle<Map> map,
                               Label* fail,
                               SmiCheckType smi_check_type) {
   if (smi_check_type == DO_SMI_CHECK) {
     JumpIfSmi(obj, fail);
   }
   cmp(FieldOperand(obj, HeapObject::kMapOffset), Immediate(map));
   j(not_equal, fail);
 }
@@ skipping 2221 matching lines @@
     cmp(length, Operand(bitmap_scratch, MemoryChunk::kSizeOffset));
     Check(less_equal, "Live Bytes Count overflow chunk size");
   }
 
   bind(&done);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32