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8012715: G1: GraphKit accesses PtrQueue::_index as int but is size_t
authorjohnc
Wed, 24 Apr 2013 14:48:43 -0700
changeset 17111 77f553b98e63
parent 17110 a8f03d38bde5
child 17112 e49af4ba7755
8012715: G1: GraphKit accesses PtrQueue::_index as int but is size_t Summary: In graphKit INT operations were generated to access PtrQueue::_index which has type size_t. This is 64 bit on 64-bit machines. No problems occur on little endian machines as long as the index fits into 32 bit, but on big endian machines the upper part is read, which is zero. This leads to unnecessary branches to the slow path in the runtime. Reviewed-by: twisti, johnc Contributed-by: Martin Doerr <martin.doerr@sap.com>
hotspot/src/share/vm/opto/graphKit.cpp file | annotate | diff | comparison | revisions 
--- a/hotspot/src/share/vm/opto/graphKit.cpp	Wed Apr 24 19:55:02 2013 +0200
+++ b/hotspot/src/share/vm/opto/graphKit.cpp	Wed Apr 24 14:48:43 2013 -0700
@@ -3564,7 +3564,8 @@
 
   Node* no_ctrl = NULL;
   Node* no_base = __ top();
-  Node* zero = __ ConI(0);
+  Node* zero  = __ ConI(0);
+  Node* zeroX = __ ConX(0);
 
   float likely  = PROB_LIKELY(0.999);
   float unlikely  = PROB_UNLIKELY(0.999);
@@ -3590,7 +3591,9 @@
 
   // if (!marking)
   __ if_then(marking, BoolTest::ne, zero); {
-    Node* index   = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw);
+    BasicType index_bt = TypeX_X->basic_type();
+    assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 PtrQueue::_index with wrong size.");
+    Node* index   = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
 
     if (do_load) {
       // load original value
@@ -3603,22 +3606,16 @@
       Node* buffer  = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
 
       // is the queue for this thread full?
-      __ if_then(index, BoolTest::ne, zero, likely); {
+      __ if_then(index, BoolTest::ne, zeroX, likely); {
 
         // decrement the index
-        Node* next_index = __ SubI(index,  __ ConI(sizeof(intptr_t)));
-        Node* next_indexX = next_index;
-#ifdef _LP64
-        // We could refine the type for what it's worth
-        // const TypeLong* lidxtype = TypeLong::make(CONST64(0), get_size_from_queue);
-        next_indexX = _gvn.transform( new (C) ConvI2LNode(next_index, TypeLong::make(0, max_jlong, Type::WidenMax)) );
-#endif
+        Node* next_index = _gvn.transform(new (C) SubXNode(index, __ ConX(sizeof(intptr_t))));
 
         // Now get the buffer location we will log the previous value into and store it
-        Node *log_addr = __ AddP(no_base, buffer, next_indexX);
+        Node *log_addr = __ AddP(no_base, buffer, next_index);
         __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw);
         // update the index
-        __ store(__ ctrl(), index_adr, next_index, T_INT, Compile::AliasIdxRaw);
+        __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw);
 
       } __ else_(); {
 
@@ -3645,26 +3642,21 @@
                             Node* buffer,
                             const TypeFunc* tf) {
 
-  Node* zero = __ ConI(0);
+  Node* zero  = __ ConI(0);
+  Node* zeroX = __ ConX(0);
   Node* no_base = __ top();
   BasicType card_bt = T_BYTE;
   // Smash zero into card. MUST BE ORDERED WRT TO STORE
   __ storeCM(__ ctrl(), card_adr, zero, oop_store, oop_alias_idx, card_bt, Compile::AliasIdxRaw);
 
   //  Now do the queue work
-  __ if_then(index, BoolTest::ne, zero); {
-
-    Node* next_index = __ SubI(index, __ ConI(sizeof(intptr_t)));
-    Node* next_indexX = next_index;
-#ifdef _LP64
-    // We could refine the type for what it's worth
-    // const TypeLong* lidxtype = TypeLong::make(CONST64(0), get_size_from_queue);
-    next_indexX = _gvn.transform( new (C) ConvI2LNode(next_index, TypeLong::make(0, max_jlong, Type::WidenMax)) );
-#endif // _LP64
-    Node* log_addr = __ AddP(no_base, buffer, next_indexX);
+  __ if_then(index, BoolTest::ne, zeroX); {
+
+    Node* next_index = _gvn.transform(new (C) SubXNode(index, __ ConX(sizeof(intptr_t))));
+    Node* log_addr = __ AddP(no_base, buffer, next_index);
 
     __ store(__ ctrl(), log_addr, card_adr, T_ADDRESS, Compile::AliasIdxRaw);
-    __ store(__ ctrl(), index_adr, next_index, T_INT, Compile::AliasIdxRaw);
+    __ store(__ ctrl(), index_adr, next_index, TypeX_X->basic_type(), Compile::AliasIdxRaw);
 
   } __ else_(); {
     __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), "g1_wb_post", card_adr, __ thread());
@@ -3725,7 +3717,7 @@
   // Now some values
   // Use ctrl to avoid hoisting these values past a safepoint, which could
   // potentially reset these fields in the JavaThread.
-  Node* index  = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw);
+  Node* index  = __ load(__ ctrl(), index_adr, TypeX_X, TypeX_X->basic_type(), Compile::AliasIdxRaw);
   Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
 
   // Convert the store obj pointer to an int prior to doing math on it
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