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8150102: C1 should fold arraylength for constant/trusted arrays

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Reviewed-by: vlivanov, kvn
This commit is contained in:
Aleksey Shipilev 2016-02-19 11:16:38 +03:00
parent 98eca9ebe8
commit 1e654fe813
1 changed files with 20 additions and 18 deletions
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38
hotspot/src/share/vm/c1/c1_Canonicalizer.cpp
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@ -222,29 +222,31 @@ void Canonicalizer::do_StoreField (StoreField* x) {
}
void Canonicalizer::do_ArrayLength (ArrayLength* x) {
NewArray* array = x->array()->as_NewArray();
if (array != NULL && array->length() != NULL) {
Constant* length = array->length()->as_Constant();
if (length != NULL) {
// do not use the Constant itself, but create a new Constant
// with same value Otherwise a Constant is live over multiple
// blocks without being registered in a state array.
NewArray* na;
Constant* ct;
if ((na = x->array()->as_NewArray()) != NULL) {
// New arrays might have the known length.
// Do not use the Constant itself, but create a new Constant
// with same value Otherwise a Constant is live over multiple
// blocks without being registered in a state array.
Constant* length;
if (na->length() != NULL &&
(length = na->length()->as_Constant()) != NULL) {
assert(length->type()->as_IntConstant() != NULL, "array length must be integer");
set_constant(length->type()->as_IntConstant()->value());
}
} else if ((ct = x->array()->as_Constant()) != NULL) {
// Constant arrays have constant lengths.
set_constant(ct->type()->as_ArrayConstant()->value()->length());
#ifdef ASSERT
} else {
LoadField* lf = x->array()->as_LoadField();
if (lf != NULL) {
ciField* field = lf->field();
if (field->is_constant() && field->is_static()) {
// final static field
ciObject* c = field->constant_value().as_object();
if (c->is_array()) {
ciArray* array = (ciArray*) c;
set_constant(array->length());
}
}
}
bool is_static_constant = (lf != NULL) && lf->field()->is_constant() && lf->field()->is_static();
assert(!is_static_constant, "Constant field loads are folded during parsing");
#endif // ASSERT
}
}