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8160360: Mismatched field loads are folded in LoadNode::Value

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Reviewed-by: kvn, thartmann
This commit is contained in:
Vladimir Ivanov 2016-07-06 15:05:28 +03:00
parent 3e441ea1a2
commit 4c31d5f745
3 changed files with 7 additions and 6 deletions
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2
hotspot/src/share/vm/opto/library_call.cpp
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@ -2337,6 +2337,8 @@ bool LibraryCallKit::inline_unsafe_access(bool is_store, const BasicType type, c
return false;
}
mismatched = (bt != type);
} else if (alias_type->adr_type() == TypeOopPtr::BOTTOM) {
mismatched = true; // conservatively mark all "wide" on-heap accesses as mismatched
}
// First guess at the value type.

9
hotspot/src/share/vm/opto/memnode.cpp
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@ -1713,9 +1713,6 @@ const Type* LoadNode::Value(PhaseGVN* phase) const {
}
}
} else if (tp->base() == Type::InstPtr) {
ciEnv* env = C->env();
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() ||
@ -1723,9 +1720,11 @@ const Type* LoadNode::Value(PhaseGVN* phase) const {
C->has_unsafe_access(),
"Field accesses must be precise" );
// For oop loads, we expect the _type to be precise.
// Optimizations for constant objects
// Optimize loads from constant fields.
const TypeInstPtr* tinst = tp->is_instptr();
ciObject* const_oop = tinst->const_oop();
if (const_oop != NULL && const_oop->is_instance()) {
if (!is_mismatched_access() && off != Type::OffsetBot && const_oop != NULL && const_oop->is_instance()) {
const Type* con_type = Type::make_constant_from_field(const_oop->as_instance(), off, is_unsigned(), memory_type());
if (con_type != NULL) {
return con_type;

2
hotspot/src/share/vm/opto/type.hpp
View File

@ -936,7 +936,7 @@ public:
};
//------------------------------TypeOopPtr-------------------------------------
// Some kind of oop (Java pointer), either klass or instance or array.
// Some kind of oop (Java pointer), either instance or array.
class TypeOopPtr : public TypePtr {
protected:
TypeOopPtr(TYPES t, PTR ptr, ciKlass* k, bool xk, ciObject* o, int offset, int instance_id,