# HG changeset patch
# User Lukas Stadler <lukas.stadler@jku.at>
# Date 1349443047 -7200
# Node ID ea845fd3c82037bdaee8957ce3f34e0af9edc1b0
# Parent  2dfab5607b3d81b9ac7f28f0c878aad1f9024124
add hashCode fast path for System.identityHashCode

diff -r 2dfab5607b3d -r ea845fd3c820 src/cpu/x86/vm/sharedRuntime_x86_64.cpp
--- a/src/cpu/x86/vm/sharedRuntime_x86_64.cpp	Fri Oct 05 13:44:26 2012 +0200
+++ b/src/cpu/x86/vm/sharedRuntime_x86_64.cpp	Fri Oct 05 15:17:27 2012 +0200
@@ -1970,14 +1970,20 @@
   int vep_offset = ((intptr_t)__ pc()) - start;
 
 #ifdef GRAAL
-  if (InlineObjectHash && method->intrinsic_id() == vmIntrinsics::_hashCode) {
+  if (InlineObjectHash && (method->intrinsic_id() == vmIntrinsics::_hashCode || method->intrinsic_id() == vmIntrinsics::_identityHashCode)) {
     // Object.hashCode can pull the hashCode from the header word
     // instead of doing a full VM transition once it's been computed.
     // Since hashCode is usually polymorphic at call sites we can't do
     // this optimization at the call site without a lot of work.
     Label slowCase;
+    Label nullCase;
     Register result = rax;
 
+    if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
+      __ cmpptr(receiver, 0);
+      __ jcc(Assembler::equal, nullCase);
+    }
+
     __ movptr(result, Address(receiver, oopDesc::mark_offset_in_bytes()));
 
     // check if locked
@@ -1997,6 +2003,12 @@
     __ jcc  (Assembler::zero, slowCase);
     __ ret(0);
 
+    if (method->intrinsic_id() == vmIntrinsics::_identityHashCode) {
+      __ bind(nullCase);
+      __ movl(result, 0);
+      __ ret(0);
+    }
+
     __ bind (slowCase);
   }
 #endif // GRAAL