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8007898: Incorrect optimization of Memory Barriers in Matcher::post_store_load_barrier()

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Generate one "fat" membar instead of set of barriers for volitile store

Reviewed-by: roland
This commit is contained in:
Vladimir Kozlov 2013-07-12 14:03:10 -07:00
parent 2d3b117249
commit 1338c067aa
3 changed files with 198 additions and 54 deletions
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20
hotspot/src/share/vm/opto/parse3.cpp
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@ -294,25 +294,7 @@ void Parse::do_put_xxx(Node* obj, ciField* field, bool is_field) {
// If reference is volatile, prevent following volatiles ops from
// floating up before the volatile write.
if (is_vol) {
// First place the specific membar for THIS volatile index. This first
// membar is dependent on the store, keeping any other membars generated
// below from floating up past the store.
int adr_idx = C->get_alias_index(adr_type);
insert_mem_bar_volatile(Op_MemBarVolatile, adr_idx, store);
// Now place a membar for AliasIdxBot for the unknown yet-to-be-parsed
// volatile alias indices. Skip this if the membar is redundant.
if (adr_idx != Compile::AliasIdxBot) {
insert_mem_bar_volatile(Op_MemBarVolatile, Compile::AliasIdxBot, store);
}
// Finally, place alias-index-specific membars for each volatile index
// that isn't the adr_idx membar. Typically there's only 1 or 2.
for( int i = Compile::AliasIdxRaw; i < C->num_alias_types(); i++ ) {
if (i != adr_idx && C->alias_type(i)->is_volatile()) {
insert_mem_bar_volatile(Op_MemBarVolatile, i, store);
}
}
insert_mem_bar(Op_MemBarVolatile); // Use fat membar
}
// If the field is final, the rules of Java say we are in <init> or <clinit>.