JIT: Use more general type guard to prevent useless trace splitting

Author: dstogov

ext/opcache/jit/zend_jit_arm64.dasc

@@ -3145,6 +3145,20 @@ static int zend_jit_type_guard(dasm_State **Dst, const zend_op *opline, uint32_t
 	return 1;
 }
 
+static int zend_jit_scalar_type_guard(dasm_State **Dst, const zend_op *opline, uint32_t var)
+{
+	int32_t exit_point = zend_jit_trace_get_exit_point(opline, 0);
+	const void *exit_addr = zend_jit_trace_get_exit_addr(exit_point);
+
+	if (!exit_addr) {
+		return 0;
+	}
+	|	MEM_ACCESS_8_WITH_UOFFSET ldrb, TMP1w, FP, var+offsetof(zval, u1.v.type), TMP1
+	|	cmp TMP1w, #IS_STRING
+	|	bhs &exit_addr
+
+	return 1;
+}
 static int zend_jit_packed_guard(dasm_State **Dst, const zend_op *opline, uint32_t var, uint32_t op_info)
 {
 	int32_t exit_point = zend_jit_trace_get_exit_point(opline, ZEND_JIT_EXIT_PACKED_GUARD);

ext/opcache/jit/zend_jit_trace.c

@@ -4758,8 +4758,18 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 						op2_info = OP2_INFO();
 						CHECK_OP2_TRACE_TYPE();
 						op1_info = OP1_INFO();
-						CHECK_OP1_TRACE_TYPE();
 						op1_def_info = OP1_DEF_INFO();
+						if (op1_type != IS_UNKNOWN && (op1_info & MAY_BE_GUARD)) {
+							if (op1_type < IS_STRING
+							 && (op1_info & (MAY_BE_ANY|MAY_BE_UNDEF)) != (op1_def_info & (MAY_BE_ANY|MAY_BE_UNDEF))) {
+								if (!zend_jit_scalar_type_guard(&dasm_state, opline, opline->op1.var)) {
+									goto jit_failure;
+								}
+								op1_info &= ~(MAY_BE_STRING|MAY_BE_ARRAY|MAY_BE_OBJECT|MAY_BE_RESOURCE|MAY_BE_REF|MAY_BE_GUARD);
+							} else {
+								CHECK_OP1_TRACE_TYPE();
+							}
+						}
 						op1_addr = OP1_REG_ADDR();
 						op1_def_addr = OP1_DEF_REG_ADDR();
 						if (orig_op1_type != IS_UNKNOWN) {

ext/opcache/jit/zend_jit_x86.dasc

@@ -3489,6 +3489,20 @@ static int zend_jit_type_guard(dasm_State **Dst, const zend_op *opline, uint32_t
 	return 1;
 }
 
+static int zend_jit_scalar_type_guard(dasm_State **Dst, const zend_op *opline, uint32_t var)
+{
+	int32_t exit_point = zend_jit_trace_get_exit_point(opline, 0);
+	const void *exit_addr = zend_jit_trace_get_exit_addr(exit_point);
+
+	if (!exit_addr) {
+		return 0;
+	}
+	|	cmp byte [FP+var+offsetof(zval, u1.v.type)], IS_STRING
+	|	jae &exit_addr
+
+	return 1;
+}
+
 static int zend_jit_packed_guard(dasm_State **Dst, const zend_op *opline, uint32_t var, uint32_t op_info)
 {
 	int32_t exit_point = zend_jit_trace_get_exit_point(opline, ZEND_JIT_EXIT_PACKED_GUARD);