6667618: disable LoadL->ConvL2I ==> LoadI optimization
Summary: this optimization causes problems (sizes of Load and Store nodes do not match) for objects initialization code and Escape Analysis
Reviewed-by: jrose, never
--- a/hotspot/src/share/vm/opto/connode.cpp Fri Feb 29 19:07:15 2008 -0800
+++ b/hotspot/src/share/vm/opto/connode.cpp Fri Feb 29 19:57:41 2008 -0800
@@ -982,34 +982,9 @@
return new (phase->C, 3) AddINode(add1,add2);
}
- // Fold up with a prior LoadL: LoadL->ConvL2I ==> LoadI
- // Requires we understand the 'endianess' of Longs.
- if( andl_op == Op_LoadL ) {
- Node *adr = andl->in(MemNode::Address);
- // VM_LITTLE_ENDIAN is #defined appropriately in the Makefiles
-#ifndef VM_LITTLE_ENDIAN
- // The transformation can cause problems on BIG_ENDIAN architectures
- // where the jint is not the same address as the jlong. Specifically, we
- // will fail to insert an anti-dependence in GCM between the LoadI and a
- // subsequent StoreL because different memory offsets provoke
- // flatten_alias_type() into indicating two different types. See bug
- // 4755222.
-
- // Node *base = adr->is_AddP() ? adr->in(AddPNode::Base) : adr;
- // adr = phase->transform( new (phase->C, 4) AddPNode(base,adr,phase->MakeConX(sizeof(jint))));
- return NULL;
-#else
- if (phase->C->alias_type(andl->adr_type())->is_volatile()) {
- // Picking up the low half by itself bypasses the atomic load and we could
- // end up with more than one non-atomic load. See bugs 4432655 and 4526490.
- // We could go to the trouble of iterating over andl's output edges and
- // punting only if there's more than one real use, but we don't bother.
- return NULL;
- }
- return new (phase->C, 3) LoadINode(andl->in(MemNode::Control),andl->in(MemNode::Memory),adr,((LoadLNode*)andl)->raw_adr_type());
-#endif
- }
-
+ // Disable optimization: LoadL->ConvL2I ==> LoadI.
+ // It causes problems (sizes of Load and Store nodes do not match)
+ // in objects initialization code and Escape Analysis.
return NULL;
}
--- a/hotspot/src/share/vm/opto/memnode.cpp Fri Feb 29 19:07:15 2008 -0800
+++ b/hotspot/src/share/vm/opto/memnode.cpp Fri Feb 29 19:57:41 2008 -0800
@@ -108,19 +108,13 @@
// Avoid independent memory operations
Node* old_mem = mem;
- if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
- InitializeNode* init = mem->in(0)->as_Initialize();
- if (init->is_complete()) { // i.e., after macro expansion
- const TypePtr* tp = t_adr->is_ptr();
- uint alias_idx = phase->C->get_alias_index(tp);
- // Free this slice from the init. It was hooked, temporarily,
- // by GraphKit::set_output_for_allocation.
- if (alias_idx > Compile::AliasIdxRaw) {
- mem = init->memory(alias_idx);
- // ...but not with the raw-pointer slice.
- }
- }
- }
+ // The code which unhooks non-raw memories from complete (macro-expanded)
+ // initializations was removed. After macro-expansion all stores catched
+ // by Initialize node became raw stores and there is no information
+ // which memory slices they modify. So it is unsafe to move any memory
+ // operation above these stores. Also in most cases hooked non-raw memories
+ // were already unhooked by using information from detect_ptr_independence()
+ // and find_previous_store().
if (mem->is_MergeMem()) {
MergeMemNode* mmem = mem->as_MergeMem();