Use immediates when possible for HBoundsCheck and HLoadKeyedFastElement

src/ia32/lithium-codegen-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 2285 matching lines @@
   DeoptimizeIf(below_equal, instr->environment());
 
   // There are two words between the frame pointer and the last argument.
   // Subtracting from length accounts for one of them add one more.
   __ mov(result, Operand(arguments, length, times_4, kPointerSize));
 }
 
 
 void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   Register elements = ToRegister(instr->elements());
-  Register key = ToRegister(instr->key());
   Register result = ToRegister(instr->result());
-  ASSERT(result.is(elements));
 
   // Load the result.
-  __ mov(result, FieldOperand(elements,
-                              key,
-                              times_pointer_size,
-                              FixedArray::kHeaderSize));
+  if (instr->key()->IsConstantOperand()) {
+    int key = ToInteger32(LConstantOperand::cast(instr->key()));
+    __ mov(result, FieldOperand(
+        elements, (key << times_pointer_size) + FixedArray::kHeaderSize));

[danno, 2011/08/10 11:03:46]

overflow check in the spirit of lithium-codegen-ia32.cc:51? Also in the 64-bit
version?

[Jakob Kummerow, 2011/08/10 12:22:48]

Done (by using BuildFastArrayOperand).

+  } else {
+    __ mov(result, FieldOperand(elements,
+                                ToRegister(instr->key()),
+                                times_pointer_size,
+                                FixedArray::kHeaderSize));
+  }
 
   // Check for the hole value.
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ cmp(result, factory()->the_hole_value());
     DeoptimizeIf(equal, instr->environment());
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFastDoubleElement(
@@ skipping 776 matching lines @@
 
   __ mov(ecx, instr->name());
   Handle<Code> ic = instr->strict_mode()
       ? isolate()->builtins()->StoreIC_Initialize_Strict()
       : isolate()->builtins()->StoreIC_Initialize();
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
 }
 
 
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
-  __ cmp(ToRegister(instr->index()), ToOperand(instr->length()));
-  DeoptimizeIf(above_equal, instr->environment());
+  if (instr->index()->IsConstantOperand()) {
+    __ cmp(ToOperand(instr->length()),
+           ToImmediate(LConstantOperand::cast(instr->index())));
+    DeoptimizeIf(below_equal, instr->environment());

[danno, 2011/08/10 11:03:46]

overflow check in the spirit of lithium-codegen-ia32.cc:51? Also in the 64-bit
version?

[Jakob Kummerow, 2011/08/10 12:22:48]

As discussed offline, nothing to overflow-check here.

+  } else {
+    __ cmp(ToRegister(instr->index()), ToOperand(instr->length()));
+    DeoptimizeIf(above_equal, instr->environment());
+  }
 }
 
 
 void LCodeGen::DoStoreKeyedSpecializedArrayElement(
     LStoreKeyedSpecializedArrayElement* instr) {
   JSObject::ElementsKind elements_kind = instr->elements_kind();
   Operand operand(BuildFastArrayOperand(instr->external_pointer(),
                                         instr->key(), elements_kind, 0));
   if (elements_kind == JSObject::EXTERNAL_FLOAT_ELEMENTS) {
     __ cvtsd2ss(xmm0, ToDoubleRegister(instr->value()));
@@ skipping 1276 matching lines @@
                                          env->deoptimization_index());
   __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION, safepoint_generator);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32