compile.c, vm.c: reduce hash merge

* compile.c (compile_array_): no hash to merge if it is empty.
* vm.c (m_core_hash_merge_kwd): just check keys if only one argument
  is given, without merging.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43269 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 15 insertions, 12 deletions

diff --git a/compile.c b/compile.c
index 2285d28805..f371cc14b9 100644
--- a/compile.c
+++ b/compile.c
@@ -2455,23 +2455,26 @@ compile_array_(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE* node_root,
 			APPEND_LIST(ret, anchor);
 			break;
 		      case COMPILE_ARRAY_TYPE_HASH:
-			if (first) {
-			    first = 0;
-			    ADD_INSN1(anchor, line, newhash, INT2FIX(i));
-			    APPEND_LIST(ret, anchor);
-			}
-			else if (i > 0) {
-			    ADD_INSN1(ret, line, putspecialobject, INT2FIX(VM_SPECIAL_OBJECT_VMCORE));
-			    ADD_INSN(ret, line, swap);
-			    APPEND_LIST(ret, anchor);
-			    ADD_SEND(ret, line, ID2SYM(id_core_hash_merge_ptr), INT2FIX(i + 1));
+			if (i > 0) {
+			    if (first) {
+				ADD_INSN1(anchor, line, newhash, INT2FIX(i));
+				APPEND_LIST(ret, anchor);
+			    }
+			    else {
+				ADD_INSN1(ret, line, putspecialobject, INT2FIX(VM_SPECIAL_OBJECT_VMCORE));
+				ADD_INSN(ret, line, swap);
+				APPEND_LIST(ret, anchor);
+				ADD_SEND(ret, line, ID2SYM(id_core_hash_merge_ptr), INT2FIX(i + 1));
+			    }
 			}
 			if (kw) {
+			    VALUE nhash = (i > 0 || !first) ? INT2FIX(2) : INT2FIX(1);
 			    ADD_INSN1(ret, line, putspecialobject, INT2FIX(VM_SPECIAL_OBJECT_VMCORE));
-			    ADD_INSN(ret, line, swap);
+			    if (i > 0 || !first) ADD_INSN(ret, line, swap);
 			    COMPILE(ret, "keyword splat", kw);
-			    ADD_SEND(ret, line, ID2SYM(id_core_hash_merge_kwd), INT2FIX(2));
+			    ADD_SEND(ret, line, ID2SYM(id_core_hash_merge_kwd), nhash);
 			}
+			first = 0;
 			break;
 		      case COMPILE_ARRAY_TYPE_ARGS:
 			APPEND_LIST(ret, anchor);