refactor newhash (revision 58463 another try) [fix GH-1600]

	* st.c (rb_hash_bulk_insert): new API to bulk insert entries
	  into a hash. Given arguments are first inserted into the
	  table at once, then reindexed. This is faster than inserting
	  things using rb_hash_aset() one by one.

	  This arrangement (rb_ prefixed function placed in st.c) is
	  unavoidable because it both touches table internal and write
	  barrier at once.

	* internal.h: delcare the new function.

	* hash.c (rb_hash_s_create): use the new function.

	* vm.c (core_hash_merge): ditto.

	* insns.def (newhash): ditto.

	* test/ruby/test_hash.rb: more coverage on hash creation.

	* test/ruby/test_literal.rb: ditto.

-----------------------------------------------------------
benchmark results:
minimum results in each 7 measurements.
Execution time (sec)
name    before  after
loop_whileloop2  0.136  0.137
vm2_bighash*     1.249  0.623

Speedup ratio: compare with the result of `before' (greater is better)
name    after
loop_whileloop2 0.996
vm2_bighash*    2.004



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58492 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 5 deletions

diff --git a/vm.c b/vm.c
index e64c072fdc..de2cee9485 100644
--- a/vm.c
+++ b/vm.c
@@ -2653,13 +2653,9 @@ static VALUE core_hash_merge_kwd(int argc, VALUE *argv);
 static VALUE
 core_hash_merge(VALUE hash, long argc, const VALUE *argv)
 {
-    long i;
-
     Check_Type(hash, T_HASH);
     VM_ASSERT(argc % 2 == 0);
-    for (i=0; i<argc; i+=2) {
-	rb_hash_aset(hash, argv[i], argv[i+1]);
-    }
+    rb_hash_bulk_insert(argc, argv, hash);
     return hash;
 }