diff -r 5b84039ca739 -r 208ebea980f8 src/cpu/sparc/vm/sparc.ad
--- a/src/cpu/sparc/vm/sparc.ad	Fri Nov 01 08:35:58 2013 -0700
+++ b/src/cpu/sparc/vm/sparc.ad	Mon Nov 04 21:59:54 2013 +0100
@@ -2916,6 +2916,9 @@
       __ bind(LSkip2);
     }
 
+    // We have no guarantee that on 64 bit the higher half of limit_reg is 0
+    __ signx(limit_reg);
+
     __ subcc(limit_reg, 1 * sizeof(jchar), chr1_reg);
     __ br(Assembler::equal, true, Assembler::pn, Ldone);
     __ delayed()->mov(O7, result_reg);  // result is difference in lengths
@@ -2973,6 +2976,9 @@
     Register  chr1_reg = result_reg;
     Register  chr2_reg =   tmp1_reg;
 
+    // We have no guarantee that on 64 bit the higher half of limit_reg is 0
+    __ signx(limit_reg);
+
     //check for alignment and position the pointers to the ends
     __ or3(str1_reg, str2_reg, chr1_reg);
     __ andcc(chr1_reg, 0x3, chr1_reg);