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6892658: C2 should optimize some stringbuilder patterns

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Reviewed-by: kvn, twisti
This commit is contained in:
Tom Rodriguez 2009-11-12 09:24:21 -08:00
parent 63cc2211ed
commit 9db2092b1b
35 changed files with 2245 additions and 115 deletions
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21
hotspot/src/share/vm/opto/memnode.cpp
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@ -1503,6 +1503,8 @@ const Type *LoadNode::Value( PhaseTransform *phase ) const {
}
}
} else if (tp->base() == Type::InstPtr) {
const TypeInstPtr* tinst = tp->is_instptr();
ciKlass* klass = tinst->klass();
assert( off != Type::OffsetBot ||
// arrays can be cast to Objects
tp->is_oopptr()->klass()->is_java_lang_Object() ||
@ -1510,6 +1512,25 @@ const Type *LoadNode::Value( PhaseTransform *phase ) const {
phase->C->has_unsafe_access(),
"Field accesses must be precise" );
// For oop loads, we expect the _type to be precise
if (OptimizeStringConcat && klass == phase->C->env()->String_klass() &&
adr->is_AddP() && off != Type::OffsetBot) {
// For constant Strings treat the fields as compile time constants.
Node* base = adr->in(AddPNode::Base);
if (base->Opcode() == Op_ConP) {
const TypeOopPtr* t = phase->type(base)->isa_oopptr();
ciObject* string = t->const_oop();
ciConstant constant = string->as_instance()->field_value_by_offset(off);
if (constant.basic_type() == T_INT) {
return TypeInt::make(constant.as_int());
} else if (constant.basic_type() == T_ARRAY) {
if (adr->bottom_type()->is_ptr_to_narrowoop()) {
return TypeNarrowOop::make_from_constant(constant.as_object());
} else {
return TypeOopPtr::make_from_constant(constant.as_object());
}
}
}
}
} else if (tp->base() == Type::KlassPtr) {
assert( off != Type::OffsetBot ||
// arrays can be cast to Objects