Use immediates when possible for HBoundsCheck and HLoadKeyedFastElement

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index ce6a9105f23abac7e1edf923ed559227e7692041..a2b551a0e5250690112447ef279292f79181224a 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -2306,15 +2306,19 @@ void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
 
 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.
-  __ movq(result, FieldOperand(elements,
-                               key,
-                               times_pointer_size,
-                               FixedArray::kHeaderSize));
+  if (instr->key()->IsConstantOperand()) {
+    int key = ToInteger32(LConstantOperand::cast(instr->key()));

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

Move into a "GetOperanXXXX" function. Or can you even use existing
"BuildFastArrayOperand"?

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

Done.

+    __ movq(result, FieldOperand(
+        elements, (key << times_pointer_size) + FixedArray::kHeaderSize));
+  } else {
+    __ movq(result, FieldOperand(elements,
+                                 ToRegister(instr->key()),
+                                 times_pointer_size,
+                                 FixedArray::kHeaderSize));
+  }
 
   // Check for the hole value.
   if (instr->hydrogen()->RequiresHoleCheck()) {
@@ -3137,12 +3141,22 @@ void LCodeGen::DoStoreKeyedSpecializedArrayElement(
 
 
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
-  if (instr->length()->IsRegister()) {
-    __ cmpq(ToRegister(instr->index()), ToRegister(instr->length()));
+  if (instr->index()->IsConstantOperand()) {
+    if (instr->length()->IsRegister()) {
+      __ cmpq(ToRegister(instr->length()),
+              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+    } else {
+      __ cmpq(ToOperand(instr->length()),
+              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+    }
   } else {
-    __ cmpq(ToRegister(instr->index()), ToOperand(instr->length()));
+    if (instr->length()->IsRegister()) {
+      __ cmpq(ToRegister(instr->length()), ToRegister(instr->index()));
+    } else {
+      __ cmpq(ToOperand(instr->length()), ToRegister(instr->index()));
+    }
   }
-  DeoptimizeIf(above_equal, instr->environment());
+  DeoptimizeIf(below_equal, instr->environment());
 }