Implement ZEND_ARRAY_KEY_EXISTS opcode to speed up array_key_exists()

NEWS

@@ -2,5 +2,8 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? ????, PHP 7.4.0alpha1
 
+- Core:
+  . Implemented request #76148 (Add array_key_exists() to the list of
+    specially compiled functions). (Majkl578)
 
 <<< NOTE: Insert NEWS from last stable release here prior to actual release! >>>

UPGRADING

@@ -23,6 +23,10 @@ PHP 7.4 UPGRADE NOTES
 2. New Features
 ========================================
 
+Core:
+  . The array_key_exists() function is now optimized into a specialized
+    ZEND_ARRAY_KEY_EXISTS instruction.
+
 ========================================
 3. Changes in SAPI modules
 ========================================

Zend/zend_compile.c

@@ -2194,6 +2194,7 @@ ZEND_API int zend_is_smart_branch(zend_op *opline) /* {{{ */
 		case ZEND_TYPE_CHECK:
 		case ZEND_DEFINED:
 		case ZEND_IN_ARRAY:
+		case ZEND_ARRAY_KEY_EXISTS:
 			return 1;
 		default:
 			return 0;
@@ -3862,6 +3863,22 @@ int zend_compile_func_get_args(znode *result, zend_ast_list *args) /* {{{ */
 }
 /* }}} */
 
+int zend_compile_func_array_key_exists(znode *result, zend_ast_list *args) /* {{{ */
+{
+	if (args->children != 2 || args->child[0]->kind == ZEND_AST_UNPACK) {
+		return FAILURE;
+	}
+
+	znode subject, needle;
+
+	zend_compile_expr(&needle, args->child[0]);
+	zend_compile_expr(&subject, args->child[1]);
+
+	zend_emit_op_tmp(result, ZEND_ARRAY_KEY_EXISTS, &needle, &subject);
+	return SUCCESS;
+}
+/* }}} */
+
 int zend_compile_func_array_slice(znode *result, zend_ast_list *args) /* {{{ */
 {
 	if (CG(active_op_array)->function_name
@@ -3969,6 +3986,8 @@ int zend_try_compile_special_func(znode *result, zend_string *lcname, zend_ast_l
 		return zend_compile_func_get_args(result, args);
 	} else if (zend_string_equals_literal(lcname, "array_slice")) {
 		return zend_compile_func_array_slice(result, args);
+	} else if (zend_string_equals_literal(lcname, "array_key_exists")) {
+		return zend_compile_func_array_key_exists(result, args);
 	} else {
 		return FAILURE;
 	}

Zend/zend_vm_def.h

@@ -6405,6 +6405,64 @@ ZEND_VM_C_LABEL(isset_no_object):
 	ZEND_VM_NEXT_OPCODE_CHECK_EXCEPTION();
 }
 
+ZEND_VM_HANDLER(199, ZEND_ARRAY_KEY_EXISTS, CV|TMPVAR|CONST, CV|TMPVAR|CONST)
+{
+	USE_OPLINE
+
+	zend_free_op free_op1, free_op2;
+	zval *key, *subject;
+	HashTable* ht;
+	int result;
+
+	SAVE_OPLINE();
+
+	key = GET_OP1_ZVAL_PTR_UNDEF(BP_VAR_R);
+	subject = GET_OP2_ZVAL_PTR_UNDEF(BP_VAR_R);
+
+ZEND_VM_C_LABEL(try_again_subject):
+	if (EXPECTED(Z_TYPE_P(subject) == IS_ARRAY)) {
+		ht = Z_ARRVAL_P(subject);
+	} else if (UNEXPECTED(Z_TYPE_P(subject) == IS_OBJECT)) {
+		ht = Z_OBJPROP_P(subject);
+	} else if (Z_ISREF_P(subject)) {
+		subject = Z_REFVAL_P(subject);
+		ZEND_VM_C_GOTO(try_again_subject);
+	} else {
+		if (OP1_TYPE == IS_CV && UNEXPECTED(Z_TYPE_INFO_P(key) == IS_UNDEF)) {
+			key = GET_OP1_UNDEF_CV(key, BP_VAR_R);
+		}
+		if (OP2_TYPE == IS_CV && UNEXPECTED(Z_TYPE_INFO_P(subject) == IS_UNDEF)) {
+			subject = GET_OP2_UNDEF_CV(subject, BP_VAR_R);
+		}
+		zend_internal_type_error(EX_USES_STRICT_TYPES(), "array_key_exists() expects parameter 2 to be array, %s given", zend_get_type_by_const(Z_TYPE_P(subject)));
+		FREE_OP2();
+		FREE_OP1();
+		ZVAL_NULL(EX_VAR(opline->result.var));
+		ZEND_VM_NEXT_OPCODE_CHECK_EXCEPTION();
+	}
+
+ZEND_VM_C_LABEL(try_again_key):
+	if (EXPECTED(Z_TYPE_P(key) == IS_STRING)) {
+		result = zend_symtable_exists_ind(ht, Z_STR_P(key));
+	} else if (EXPECTED(Z_TYPE_P(key) == IS_LONG)) {
+		result = zend_hash_index_exists(ht, Z_LVAL_P(key));
+	} else if (UNEXPECTED(Z_TYPE_P(key) == IS_NULL)) {
+		result = zend_symtable_exists_ind(ht, ZSTR_EMPTY_ALLOC());
+	} else if (Z_ISREF_P(key)) {
+		key = Z_REFVAL_P(key);
+		ZEND_VM_C_GOTO(try_again_key);
+	} else {
+		zend_error(E_WARNING, "array_key_exists(): The first argument should be either a string or an integer");
+		result = 0;
+	}
+
+	FREE_OP2();
+	FREE_OP1();
+	ZEND_VM_SMART_BRANCH(result, 1);
+	ZVAL_BOOL(EX_VAR(opline->result.var), result);
+	ZEND_VM_NEXT_OPCODE_CHECK_EXCEPTION();
+}
+
 ZEND_VM_COLD_HANDLER(79, ZEND_EXIT, CONST|TMPVAR|UNUSED|CV, ANY)
 {
 	USE_OPLINE