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8031755: Type speculation should be used to optimize explicit null checks

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Feed profiling data about reference nullness to type speculation.

Reviewed-by: kvn, iveresov
This commit is contained in:
Roland Westrelin 2014-03-31 09:08:53 +02:00
parent f5d6f0ceb8
commit fa3b0a8f47
16 changed files with 683 additions and 418 deletions
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14
hotspot/src/share/vm/opto/connode.cpp
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@ -399,7 +399,7 @@ Node *ConstraintCastNode::Identity( PhaseTransform *phase ) {
// Take 'join' of input and cast-up type
const Type *ConstraintCastNode::Value( PhaseTransform *phase ) const {
if( in(0) && phase->type(in(0)) == Type::TOP ) return Type::TOP;
const Type* ft = phase->type(in(1))->filter_speculative(_type);
const Type* ft = phase->type(in(1))->filter_speculative(_type);
#ifdef ASSERT
// Previous versions of this function had some special case logic,
@ -493,7 +493,17 @@ const Type *CheckCastPPNode::Value( PhaseTransform *phase ) const {
result = my_type->cast_to_ptr_type( my_type->join_ptr(in_ptr) );
}
}
return result;
// This is the code from TypePtr::xmeet() that prevents us from
// having 2 ways to represent the same type. We have to replicate it
// here because we don't go through meet/join.
if (result->remove_speculative() == result->speculative()) {
result = result->remove_speculative();
}
// Same as above: because we don't go through meet/join, remove the
// speculative type if we know we won't use it.
return result->cleanup_speculative();
// JOIN NOT DONE HERE BECAUSE OF INTERFACE ISSUES.
// FIX THIS (DO THE JOIN) WHEN UNION TYPES APPEAR!