Implement optimization to cast values instead of verifying the type

Author: Girgias

Zend/Optimizer/dfa_pass.c

@@ -318,6 +318,53 @@ static inline bool can_elide_return_type_check(
 	return false;
 }
 
+static inline bool can_return_value_safely_be_coerced(
+	const zend_op_array *op_array, const zend_ssa *ssa, const zend_ssa_op *ssa_op, zend_op *opline
+) {
+	const uint32_t return_type_mask = ZEND_TYPE_FULL_MASK(op_array->arg_info[-1].type);
+	const zend_ssa_var_info *use_info = &ssa->var_info[ssa_op->op1_use];
+
+	/* Type preference order: int -> float -> string -> bool */
+	/* Can always safely cast booleans to inter */
+	if (return_type_mask & MAY_BE_LONG) {
+		if (use_info->type & MAY_BE_BOOL) {
+			opline->opcode = ZEND_CAST;
+			opline->extended_value = IS_LONG;
+			return true;
+		}
+		return false;
+	}
+	if (return_type_mask & MAY_BE_DOUBLE) {
+		/* Can always safely cast booleans, and integers to float */
+		if (use_info->type & (MAY_BE_LONG|MAY_BE_BOOL)) {
+			opline->opcode = ZEND_CAST;
+			opline->extended_value = IS_DOUBLE;
+			return true;
+		}
+		return false;
+	}
+	/* Can always safely cast booleans, and integers to string,
+	 * float value must not be NAN */
+	if (return_type_mask & MAY_BE_STRING) {
+		if (use_info->type & (MAY_BE_LONG|MAY_BE_BOOL)) {
+			opline->opcode = ZEND_CAST;
+			opline->extended_value = IS_STRING;
+			return true;
+		}
+		return false;
+	}
+	return false;
+	if ((return_type_mask & MAY_BE_BOOL) == MAY_BE_BOOL) {
+		/* Can always safely cast integers and strings to bool,
+		 * float value must not be NAN */
+		if (use_info->type & (MAY_BE_LONG|MAY_BE_STRING)) {
+			opline->opcode = ZEND_BOOL;
+			return true;
+		}
+		return false;
+	}
+}
+
 static bool opline_supports_assign_contraction(
 		zend_op_array *op_array, zend_ssa *ssa, zend_op *opline, int src_var, uint32_t cv_var) {
 	if (opline->opcode == ZEND_NEW) {
@@ -1289,6 +1336,8 @@ void zend_dfa_optimize_op_array(zend_op_array *op_array, zend_optimizer_ctx *ctx
 
 						MAKE_NOP(opline);
 						remove_nops = 1;
+					} else if (can_return_value_safely_be_coerced(op_array, ssa, &ssa->ops[op_1], opline)) {
+						continue;
 					}
 				}
 			}

ext/opcache/tests/opt/type_inference_class_consts1.phpt

@@ -73,7 +73,7 @@ Test1::getStaticFoo:
      ; (after optimizer)
      ; %s
 0000 T0 = FETCH_CLASS_CONSTANT (static) (exception) string("FOO")
-0001 VERIFY_RETURN_TYPE T0
+0001 CAST (long) T0
 0002 RETURN T0
 LIVE RANGES:
      0: 0001 - 0002 (tmp/var)

ext/opcache/tests/opt/type_inference_class_consts4.phpt

@@ -57,7 +57,7 @@ Test4::getSelfA:
      ; (after optimizer)
      ; %s
 0000 T0 = FETCH_CLASS_CONSTANT (self) (exception) string("A")
-0001 VERIFY_RETURN_TYPE T0
+0001 CAST (long) T0
 0002 RETURN T0
 LIVE RANGES:
      0: 0001 - 0002 (tmp/var)
@@ -67,7 +67,7 @@ Test4::getSelfB:
      ; (after optimizer)
      ; %s
 0000 T0 = FETCH_CLASS_CONSTANT (self) (exception) string("B")
-0001 VERIFY_RETURN_TYPE T0
+0001 CAST (long) T0
 0002 RETURN T0
 LIVE RANGES:
      0: 0001 - 0002 (tmp/var)
@@ -77,7 +77,7 @@ Test4::getStaticA:
      ; (after optimizer)
      ; %s
 0000 T0 = FETCH_CLASS_CONSTANT (static) (exception) string("A")
-0001 VERIFY_RETURN_TYPE T0
+0001 CAST (long) T0
 0002 RETURN T0
 LIVE RANGES:
      0: 0001 - 0002 (tmp/var)
@@ -87,7 +87,7 @@ Test4::getStaticB:
      ; (after optimizer)
      ; %s
 0000 T0 = FETCH_CLASS_CONSTANT (static) (exception) string("B")
-0001 VERIFY_RETURN_TYPE T0
+0001 CAST (long) T0
 0002 RETURN T0
 LIVE RANGES:
      0: 0001 - 0002 (tmp/var)

ext/opcache/tests/opt/verify_return_type_to_cast.phpt

@@ -118,7 +118,7 @@ boolToInt:
      ; (after optimizer)
      ; %s:19-21
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (long) CV0($v)
 0002 RETURN CV0($v)
 
 strToFloat:
@@ -134,15 +134,15 @@ intToFloat:
      ; (after optimizer)
      ; %s:26-28
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (double) CV0($v)
 0002 RETURN CV0($v)
 
 boolToFloat:
      ; (lines=3, args=1, vars=1, tmps=0)
      ; (after optimizer)
      ; %s:29-31
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (double) CV0($v)
 0002 RETURN CV0($v)
 
 floatToString:
@@ -158,15 +158,15 @@ intToString:
      ; (after optimizer)
      ; %s:36-38
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (string) CV0($v)
 0002 RETURN CV0($v)
 
 boolToString:
      ; (lines=3, args=1, vars=1, tmps=0)
      ; (after optimizer)
      ; %s:39-41
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (string) CV0($v)
 0002 RETURN CV0($v)
 
 floatToUnion:
@@ -182,15 +182,15 @@ intToUnion:
      ; (after optimizer)
      ; %s:46-48
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (double) CV0($v)
 0002 RETURN CV0($v)
 
 boolToUnion:
      ; (lines=3, args=1, vars=1, tmps=0)
      ; (after optimizer)
      ; %s:49-51
 0000 CV0($v) = RECV 1
-0001 VERIFY_RETURN_TYPE CV0($v)
+0001 CAST (long) CV0($v)
 0002 RETURN CV0($v)
 
 stringToUnion: