diff --git a/ChangeLog b/ChangeLog
index befec75f86..73a47277ec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Jan 16 10:51:19 2016  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
+
+	* enc/unicode.c: fix implicit conversion error with clang. fixup r53548.
+	* string.c: ditto.
+
 Sat Jan 16 10:31:00 2016  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* common.mk: test-sample was changed to test-basic.
diff --git a/enc/unicode.c b/enc/unicode.c
index 2f45f2f88c..365283e591 100644
--- a/enc/unicode.c
+++ b/enc/unicode.c
@@ -630,5 +630,5 @@ onigenc_unicode_case_map(OnigCaseFoldType* flags,
 	}
 	to += ONIGENC_CODE_TO_MBC(enc, code, to);
     }
-    return to-to_start;
+    return (int)(to-to_start);
 }
diff --git a/string.c b/string.c
index 6e9bde8e76..c78d30fe63 100644
--- a/string.c
+++ b/string.c
@@ -5672,7 +5672,7 @@ rb_str_casemap(VALUE source, OnigCaseFoldType *flags, rb_encoding *enc)
 
     while (source_current < source_end) {
 	/* increase multiplier using buffer count to converge quickly */
-	int capa = (source_end-source_current)*++buffer_count + CASE_MAPPING_ADDITIONAL_LENGTH;
+	int capa = (int)(source_end-source_current)*++buffer_count + CASE_MAPPING_ADDITIONAL_LENGTH;
 	current_buffer->next = (mapping_buffer*)ALLOC_N(char, sizeof(mapping_buffer)+capa);
 	current_buffer = current_buffer->next;
 	current_buffer->next = NULL;