6667618: disable LoadL->ConvL2I ==> LoadI optimization
This optimization causes problems (sizes of Load and Store nodes do not match) for objects initialization code and Escape Analysis Reviewed-by: jrose, never
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hotspot/src/share/vm/opto
@ -982,34 +982,9 @@ Node *ConvL2INode::Ideal(PhaseGVN *phase, bool can_reshape) {
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return new (phase->C, 3) AddINode(add1,add2);
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}
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// Fold up with a prior LoadL: LoadL->ConvL2I ==> LoadI
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// Requires we understand the 'endianess' of Longs.
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if( andl_op == Op_LoadL ) {
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Node *adr = andl->in(MemNode::Address);
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// VM_LITTLE_ENDIAN is #defined appropriately in the Makefiles
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#ifndef VM_LITTLE_ENDIAN
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// The transformation can cause problems on BIG_ENDIAN architectures
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// where the jint is not the same address as the jlong. Specifically, we
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// will fail to insert an anti-dependence in GCM between the LoadI and a
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// subsequent StoreL because different memory offsets provoke
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// flatten_alias_type() into indicating two different types. See bug
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// 4755222.
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// Node *base = adr->is_AddP() ? adr->in(AddPNode::Base) : adr;
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// adr = phase->transform( new (phase->C, 4) AddPNode(base,adr,phase->MakeConX(sizeof(jint))));
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return NULL;
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#else
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if (phase->C->alias_type(andl->adr_type())->is_volatile()) {
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// Picking up the low half by itself bypasses the atomic load and we could
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// end up with more than one non-atomic load. See bugs 4432655 and 4526490.
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// We could go to the trouble of iterating over andl's output edges and
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// punting only if there's more than one real use, but we don't bother.
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return NULL;
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}
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return new (phase->C, 3) LoadINode(andl->in(MemNode::Control),andl->in(MemNode::Memory),adr,((LoadLNode*)andl)->raw_adr_type());
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#endif
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}
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// Disable optimization: LoadL->ConvL2I ==> LoadI.
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// It causes problems (sizes of Load and Store nodes do not match)
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// in objects initialization code and Escape Analysis.
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return NULL;
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}
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@ -108,19 +108,13 @@ Node *MemNode::Ideal_common(PhaseGVN *phase, bool can_reshape) {
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// Avoid independent memory operations
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Node* old_mem = mem;
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if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
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InitializeNode* init = mem->in(0)->as_Initialize();
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if (init->is_complete()) { // i.e., after macro expansion
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const TypePtr* tp = t_adr->is_ptr();
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uint alias_idx = phase->C->get_alias_index(tp);
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// Free this slice from the init. It was hooked, temporarily,
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// by GraphKit::set_output_for_allocation.
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if (alias_idx > Compile::AliasIdxRaw) {
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mem = init->memory(alias_idx);
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// ...but not with the raw-pointer slice.
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}
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}
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}
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// The code which unhooks non-raw memories from complete (macro-expanded)
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// initializations was removed. After macro-expansion all stores catched
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// by Initialize node became raw stores and there is no information
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// which memory slices they modify. So it is unsafe to move any memory
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// operation above these stores. Also in most cases hooked non-raw memories
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// were already unhooked by using information from detect_ptr_independence()
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// and find_previous_store().
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if (mem->is_MergeMem()) {
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MergeMemNode* mmem = mem->as_MergeMem();
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