compile.c: insn before pop

* compile.c (iseq_peephole_optimize): more eliminatable
  instructions before `pop` without side effects.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63246 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

compile.c

@@ -2909,6 +2909,11 @@ iseq_peephole_optimize(rb_iseq_t *iseq, LINK_ELEMENT *list, const int do_tailcal
 	    enum ruby_vminsn_type previ = ((INSN *)prev)->insn_id;
 	    if (previ == BIN(putobject) || previ == BIN(putnil) ||
 		previ == BIN(putself) || previ == BIN(putstring) ||
+		previ == BIN(dup) ||
+		previ == BIN(getlocal) ||
+		previ == BIN(getblockparam) ||
+		previ == BIN(getblockparamproxy) ||
+		/* getinstancevariable may issue a warning */
 		previ == BIN(duparray)) {
 		/* just push operand or static value and pop soon, no
 		 * side effects */