Optimize Smi keys for KeyedLoads

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 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 2630 matching lines @@
 }
 
 
 void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   Register result = ToRegister(instr->result());
 
   // Load the result.
   __ mov(result,
          BuildFastArrayOperand(instr->elements(),
                                instr->key(),
+                               instr->hydrogen()->key()->representation(),
                                FAST_ELEMENTS,
                                FixedArray::kHeaderSize - kHeapObjectTag,
                                instr->additional_index()));
 
   // Check for the hole value.
   if (instr->hydrogen()->RequiresHoleCheck()) {
     if (IsFastSmiElementsKind(instr->hydrogen()->elements_kind())) {
       __ test(result, Immediate(kSmiTagMask));
       DeoptimizeIf(not_equal, instr->environment());
     } else {
       __ cmp(result, factory()->the_hole_value());
       DeoptimizeIf(equal, instr->environment());
     }
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFastDoubleElement(
     LLoadKeyedFastDoubleElement* instr) {
   XMMRegister result = ToDoubleRegister(instr->result());
 
   if (instr->hydrogen()->RequiresHoleCheck()) {
     int offset = FixedDoubleArray::kHeaderSize - kHeapObjectTag +
         sizeof(kHoleNanLower32);
     Operand hole_check_operand = BuildFastArrayOperand(
         instr->elements(), instr->key(),
+        instr->hydrogen()->key()->representation(),
         FAST_DOUBLE_ELEMENTS,
         offset,
         instr->additional_index());
     __ cmp(hole_check_operand, Immediate(kHoleNanUpper32));
     DeoptimizeIf(equal, instr->environment());
   }
 
   Operand double_load_operand = BuildFastArrayOperand(
       instr->elements(),
       instr->key(),
+      instr->hydrogen()->key()->representation(),
       FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
   __ movdbl(result, double_load_operand);
 }
 
 
 Operand LCodeGen::BuildFastArrayOperand(
     LOperand* elements_pointer,
     LOperand* key,
+    Representation key_representation,
     ElementsKind elements_kind,
     uint32_t offset,
     uint32_t additional_index) {
   Register elements_pointer_reg = ToRegister(elements_pointer);
   int shift_size = ElementsKindToShiftSize(elements_kind);
+  if (key_representation.IsTagged() && shift_size >= 1) {

[Michael Starzinger, 2012/07/19 21:02:23]

Can we also make this condition use !ExternalArrayOpRequiresTemp(...) and
instead ASSERT(shift_size >= kSmiTagSize)?

[danno, 2012/07/20 09:51:57]

Done.

[danno, 2012/07/20 10:40:27]

Actually, it turns out that ExternalArrayOpRequiresTemp test something
difference, and one is not replaceable by the other, so I'm leaving the code
as-is.

[Michael Starzinger, 2012/07/20 10:50:25]

I see, OK. Just use the kSmiTagSize constant.

+    shift_size -= 1;

[Michael Starzinger, 2012/07/19 21:02:23]

Can we use kSmiTagSize here?

[danno, 2012/07/20 09:51:57]

Done.

+  }
   if (key->IsConstantOperand()) {
     int constant_value = ToInteger32(LConstantOperand::cast(key));
     if (constant_value & 0xF0000000) {
       Abort("array index constant value too big");
     }
     return Operand(elements_pointer_reg,
                    ((constant_value + additional_index) << shift_size)
                        + offset);
   } else {
     ScaleFactor scale_factor = static_cast<ScaleFactor>(shift_size);
     return Operand(elements_pointer_reg,
                    ToRegister(key),
                    scale_factor,
                    offset + (additional_index << shift_size));
   }
 }
 
 
 void LCodeGen::DoLoadKeyedSpecializedArrayElement(
     LLoadKeyedSpecializedArrayElement* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  Operand operand(BuildFastArrayOperand(instr->external_pointer(),
-                                        instr->key(),
-                                        elements_kind,
-                                        0,
-                                        instr->additional_index()));
+  LOperand* key = instr->key();
+  if (!key->IsConstantOperand() &&
+      ExternalArrayOpRequiresTemp(instr->hydrogen()->key()->representation(),
+                                  elements_kind)) {
+    __ SmiUntag(ToRegister(key));
+  }
+  Operand operand(BuildFastArrayOperand(
+      instr->external_pointer(),
+      key,
+      instr->hydrogen()->key()->representation(),
+      elements_kind,
+      0,
+      instr->additional_index()));
   if (elements_kind == EXTERNAL_FLOAT_ELEMENTS) {
     XMMRegister result(ToDoubleRegister(instr->result()));
     __ movss(result, operand);
     __ cvtss2sd(result, result);
   } else if (elements_kind == EXTERNAL_DOUBLE_ELEMENTS) {
     __ movdbl(ToDoubleRegister(instr->result()), operand);
   } else {
     Register result(ToRegister(instr->result()));
     switch (elements_kind) {
       case EXTERNAL_BYTE_ELEMENTS:
@@ skipping 932 matching lines @@
   } else {
     __ cmp(ToRegister(instr->index()), ToOperand(instr->length()));
     DeoptimizeIf(above_equal, instr->environment());
   }
 }
 
 
 void LCodeGen::DoStoreKeyedSpecializedArrayElement(
     LStoreKeyedSpecializedArrayElement* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  Operand operand(BuildFastArrayOperand(instr->external_pointer(),
-                                        instr->key(),
-                                        elements_kind,
-                                        0,
-                                        instr->additional_index()));
+  LOperand* key = instr->key();
+  if (!key->IsConstantOperand() &&
+      ExternalArrayOpRequiresTemp(instr->hydrogen()->key()->representation(),
+                                  elements_kind)) {
+    __ SmiUntag(ToRegister(key));
+  }
+  Operand operand(BuildFastArrayOperand(
+      instr->external_pointer(),
+      key,
+      instr->hydrogen()->key()->representation(),
+      elements_kind,
+      0,
+      instr->additional_index()));
   if (elements_kind == EXTERNAL_FLOAT_ELEMENTS) {
     __ cvtsd2ss(xmm0, ToDoubleRegister(instr->value()));
     __ movss(operand, xmm0);
   } else if (elements_kind == EXTERNAL_DOUBLE_ELEMENTS) {
     __ movdbl(operand, ToDoubleRegister(instr->value()));
   } else {
     Register value = ToRegister(instr->value());
     switch (elements_kind) {
       case EXTERNAL_PIXEL_ELEMENTS:
       case EXTERNAL_UNSIGNED_BYTE_ELEMENTS:
@@ skipping 26 matching lines @@
 
 
 void LCodeGen::DoStoreKeyedFastElement(LStoreKeyedFastElement* instr) {
   Register value = ToRegister(instr->value());
   Register elements = ToRegister(instr->object());
   Register key = instr->key()->IsRegister() ? ToRegister(instr->key()) : no_reg;
 
   Operand operand = BuildFastArrayOperand(
       instr->object(),
       instr->key(),
+      instr->hydrogen()->key()->representation(),
       FAST_ELEMENTS,
       FixedArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
   __ mov(operand, value);
 
   if (instr->hydrogen()->NeedsWriteBarrier()) {
     ASSERT(!instr->key()->IsConstantOperand());
     HType type = instr->hydrogen()->value()->type();
     SmiCheck check_needed =
         type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
@@ skipping 21 matching lines @@
 
     ExternalReference canonical_nan_reference =
         ExternalReference::address_of_canonical_non_hole_nan();
     __ movdbl(value, Operand::StaticVariable(canonical_nan_reference));
     __ bind(&have_value);
   }
 
   Operand double_store_operand = BuildFastArrayOperand(
       instr->elements(),
       instr->key(),
+      instr->hydrogen()->key()->representation(),
       FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
   __ movdbl(double_store_operand, value);
 }
 
 
 void LCodeGen::DoStoreKeyedGeneric(LStoreKeyedGeneric* instr) {
   ASSERT(ToRegister(instr->context()).is(esi));
   ASSERT(ToRegister(instr->object()).is(edx));
@@ skipping 1550 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32