diff -r f95d63e2154a -r ac637b7220d1 src/cpu/x86/vm/c1_FrameMap_x86.cpp
--- a/src/cpu/x86/vm/c1_FrameMap_x86.cpp	Tue Nov 23 13:22:55 2010 -0800
+++ b/src/cpu/x86/vm/c1_FrameMap_x86.cpp	Tue Nov 30 23:23:40 2010 -0800
@@ -158,9 +158,11 @@
   map_register( 6, r8);    r8_opr = LIR_OprFact::single_cpu(6);
   map_register( 7, r9);    r9_opr = LIR_OprFact::single_cpu(7);
   map_register( 8, r11);  r11_opr = LIR_OprFact::single_cpu(8);
-  map_register( 9, r12);  r12_opr = LIR_OprFact::single_cpu(9);
-  map_register(10, r13);  r13_opr = LIR_OprFact::single_cpu(10);
-  map_register(11, r14);  r14_opr = LIR_OprFact::single_cpu(11);
+  map_register( 9, r13);  r13_opr = LIR_OprFact::single_cpu(9);
+  map_register(10, r14);  r14_opr = LIR_OprFact::single_cpu(10);
+  // r12 is allocated conditionally. With compressed oops it holds
+  // the heapbase value and is not visible to the allocator.
+  map_register(11, r12);  r12_opr = LIR_OprFact::single_cpu(11);
   // The unallocatable registers are at the end
   map_register(12, r10);  r10_opr = LIR_OprFact::single_cpu(12);
   map_register(13, r15);  r15_opr = LIR_OprFact::single_cpu(13);
@@ -191,9 +193,9 @@
   _caller_save_cpu_regs[6]  = r8_opr;
   _caller_save_cpu_regs[7]  = r9_opr;
   _caller_save_cpu_regs[8]  = r11_opr;
-  _caller_save_cpu_regs[9]  = r12_opr;
-  _caller_save_cpu_regs[10] = r13_opr;
-  _caller_save_cpu_regs[11] = r14_opr;
+  _caller_save_cpu_regs[9]  = r13_opr;
+  _caller_save_cpu_regs[10] = r14_opr;
+  _caller_save_cpu_regs[11] = r12_opr;
 #endif // _LP64