[hydrogen] don't bailout assignments to consts

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 23db874067c928394da6b5c1bea8389458cad2ce..5a91a2cdfccdfbb0f7b622922ccf524b468bd1ef 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2165,9 +2165,19 @@ void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register result = ToRegister(instr->result());
   __ mov(result, ContextOperand(context, instr->slot_index()));
+
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ cmp(result, factory()->the_hole_value());
-    DeoptimizeIf(equal, instr->environment());
+    if (instr->hydrogen()->DeoptimizesOnHole()) {
+      DeoptimizeIf(equal, instr->environment());
+    } else {
+      Label is_not_hole;
+      __ j(not_equal, &is_not_hole, Label::kNear);
+

[Steven, 2011/12/12 13:12:44]

Those blank lines do not help readability. Could you remove them please?

+      __ mov(result, factory()->undefined_value());
+
+      __ bind(&is_not_hole);
+    }
   }
 }
 
@@ -2175,11 +2185,19 @@ void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
 void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register value = ToRegister(instr->value());
+
+  Label skip_assignment;
+
   Operand target = ContextOperand(context, instr->slot_index());
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ cmp(target, factory()->the_hole_value());
-    DeoptimizeIf(equal, instr->environment());
+    if (instr->hydrogen()->DeoptimizesOnHole()) {
+      DeoptimizeIf(equal, instr->environment());
+    } else {
+      __ j(not_equal, &skip_assignment, Label::kNear);
+    }
   }
+
   __ mov(target, value);
   if (instr->hydrogen()->NeedsWriteBarrier()) {
     HType type = instr->hydrogen()->value()->type();
@@ -2195,6 +2213,8 @@ void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
                               EMIT_REMEMBERED_SET,
                               check_needed);
   }
+
+  __ bind(&skip_assignment);
 }