src/hotspot/cpu/x86/jniFastGetField_x86_64.cpp

@@ -33,13 +33,10 @@
 
 #define __ masm->
 
 #define BUFFER_SIZE 30*wordSize
 
-// Instead of issuing lfence for LoadLoad barrier, we create data dependency
-// between loads, which is more efficient than lfence.
-
 // Common register usage:
 // rax/xmm0: result
 // c_rarg0:    jni env
 // c_rarg1:    obj
 // c_rarg2:    jfield id

@@ -75,16 +72,10 @@
   ExternalAddress counter(SafepointSynchronize::safepoint_counter_addr());
   __ mov32 (rcounter, counter);
   __ mov   (robj, c_rarg1);
   __ testb (rcounter, 1);
   __ jcc (Assembler::notZero, slow);
-
-  __ xorptr(robj, rcounter);
-  __ xorptr(robj, rcounter);  // obj, since
-                              // robj ^ rcounter ^ rcounter == robj
-                              // robj is data dependent on rcounter.
-
   __ mov   (roffset, c_rarg2);
   __ shrptr(roffset, 2);                         // offset
 
   // Both robj and rtmp are clobbered by try_resolve_jobject_in_native.
   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();

@@ -101,16 +92,11 @@
     case T_INT:     __ movl   (rax, Address(robj, roffset, Address::times_1)); break;
     case T_LONG:    __ movq   (rax, Address(robj, roffset, Address::times_1)); break;
     default:        ShouldNotReachHere();
   }
 
-  // create data dependency on rax
-  __ lea(rcounter_addr, counter);
-  __ xorptr(rcounter_addr, rax);
-  __ xorptr(rcounter_addr, rax);
-  __ cmpl (rcounter, Address(rcounter_addr, 0));
-
+  __ cmp32 (rcounter, counter);
   __ jcc (Assembler::notEqual, slow);
 
   __ ret (0);
 
   slowcase_entry_pclist[count++] = __ pc();

@@ -176,15 +162,10 @@
   __ mov32 (rcounter, counter);
   __ mov   (robj, c_rarg1);
   __ testb (rcounter, 1);
   __ jcc (Assembler::notZero, slow);
 
-  __ xorptr(robj, rcounter);
-  __ xorptr(robj, rcounter);  // obj, since
-                              // robj ^ rcounter ^ rcounter == robj
-                              // robj is data dependent on rcounter.
-
   // Both robj and rtmp are clobbered by try_resolve_jobject_in_native.
   BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
   bs->try_resolve_jobject_in_native(masm, /* jni_env */ c_rarg0, robj, rtmp, slow);
   DEBUG_ONLY(__ movl(rtmp, 0xDEADC0DE);)
 

@@ -196,17 +177,11 @@
   switch (type) {
     case T_FLOAT:  __ movflt (xmm0, Address(robj, roffset, Address::times_1)); break;
     case T_DOUBLE: __ movdbl (xmm0, Address(robj, roffset, Address::times_1)); break;
     default:        ShouldNotReachHere();
   }
-
-  __ lea(rcounter_addr, counter);
-  __ movdq (rax, xmm0);
-  // counter address is data dependent on xmm0.
-  __ xorptr(rcounter_addr, rax);
-  __ xorptr(rcounter_addr, rax);
-  __ cmpl (rcounter, Address(rcounter_addr, 0));
+  __ cmp32 (rcounter, counter);
   __ jcc (Assembler::notEqual, slow);
 
   __ ret (0);
 
   slowcase_entry_pclist[count++] = __ pc();