--- old/src/hotspot/share/c1/c1_LIRGenerator.cpp	2018-11-27 23:21:12.752695815 -0800
+++ new/src/hotspot/share/c1/c1_LIRGenerator.cpp	2018-11-27 23:21:12.632691243 -0800
@@ -1570,9 +1570,17 @@
 
 #ifndef _LP64
   LIR_Opr index_op = index.result();
+  // FIXME -- on 32-bit, the shift below can overflow, so we need to check that
+  // the top (value_array_klass->log2_element_size()+1) bits of index_op must be zero, or
+  // else throw ArrayIndexOutOfBoundsException
 #else
   LIR_Opr index_op = new_register(T_LONG);
-  __ convert(Bytecodes::_i2l, index.result(), index_op);
+  if (index.result()->is_constant()) {
+    jint const_index = index.result()->as_jint();
+    __ move(LIR_OprFact::longConst(const_index), index_op);
+  } else {
+    __ convert(Bytecodes::_i2l, index.result(), index_op);
+  }
 #endif
   // Need to shift manually, as LIR_Address can scale only up to 3.
   __ shift_left(index_op, value_array_klass->log2_element_size(), index_op);