Convert ZEND_ECHO operand to string after sccp

And filter out echoes of the empty string (e.g. false/null)

Split out of php#5097

Author: TysonAndre

ext/opcache/Optimizer/zend_optimizer.c

@@ -340,6 +340,22 @@ int zend_optimizer_update_op1_const(zend_op_array *op_array,
 		case ZEND_FETCH_LIST_R:
 		case ZEND_COPY_TMP:
 			return 0;
+		case ZEND_ECHO:
+		{
+			zval zv;
+			if (Z_TYPE_P(val) != IS_STRING && zend_optimizer_eval_cast(&zv, IS_STRING, val) == SUCCESS) {
+				zval_ptr_dtor_nogc(val);
+				val = &zv;
+			}
+			opline->op1.constant = zend_optimizer_add_literal(op_array, val);
+			if (Z_TYPE_P(val) == IS_STRING && Z_STRLEN_P(val) == 0) {
+				MAKE_NOP(opline);
+			}
+			/* TODO: In a subsequent pass, *after* this step and compacting nops, combine consecutive ZEND_ECHOs using the block information from ssa->cfg */
+			/* (e.g. for ext/opcache/tests/opt/sccp_010.phpt) */
+			/* https://github.com/php/php-src/pull/5097#issuecomment-577306560 */
+			break;
+		}
 		case ZEND_CONCAT:
 		case ZEND_FAST_CONCAT:
 		case ZEND_FETCH_R:

ext/opcache/tests/opt/sccp_002.phpt

@@ -32,6 +32,6 @@ foo: ; (lines=4, args=1, vars=1, tmps=0)
     ; (after optimizer)
     ; %ssccp_002.php:2-12
 L0 (2):     CV0($x) = RECV 1
-L1 (9):     ECHO int(1)
-L2 (11):    ECHO int(1)
+L1 (9):     ECHO string("1")
+L2 (11):    ECHO string("1")
 L3 (12):    RETURN null

ext/opcache/tests/opt/sccp_003.phpt

@@ -31,6 +31,6 @@ L0 (14):    RETURN int(1)
 foo: ; (lines=3, args=0, vars=0, tmps=0)
     ; (after optimizer)
     ; %ssccp_003.php:2-12
-L0 (9):     ECHO int(1)
-L1 (11):    ECHO int(1)
+L0 (9):     ECHO string("1")
+L1 (11):    ECHO string("1")
 L2 (12):    RETURN null

ext/opcache/tests/opt/sccp_004.phpt

@@ -35,6 +35,6 @@ foo: ; (lines=4, args=1, vars=1, tmps=0)
     ; (after optimizer)
     ; %ssccp_004.php:2-15
 L0 (2):     CV0($x) = RECV 1
-L1 (11):    ECHO bool(true)
-L2 (14):    ECHO int(1)
+L1 (11):    ECHO string("1")
+L2 (14):    ECHO string("1")
 L3 (15):    RETURN null

ext/opcache/tests/opt/sccp_005.phpt

@@ -25,5 +25,5 @@ foo: ; (lines=3, args=1, vars=1, tmps=0)
     ; (after optimizer)
     ; %ssccp_005.php:2-5
 L0 (2):     CV0($x) = RECV 1
-L1 (4):     ECHO int(2)
+L1 (4):     ECHO string("2")
 L2 (5):     RETURN null

ext/opcache/tests/opt/sccp_007.phpt

@@ -29,5 +29,5 @@ foo: ; (lines=3, args=1, vars=1, tmps=0)
     ; (after optimizer)
     ; %ssccp_007.php:2-9
 L0 (2):     CV0($x) = RECV 1
-L1 (8):     ECHO int(0)
+L1 (8):     ECHO string("0")
 L2 (9):     RETURN null

ext/opcache/tests/opt/sccp_009.phpt

@@ -26,5 +26,5 @@ foo: ; (lines=3, args=1, vars=1, tmps=0)
     ; (after optimizer)
     ; %ssccp_009.php:2-6
 L0 (2):     CV0($x) = RECV 1
-L1 (5):     ECHO int(2)
+L1 (5):     ECHO string("2")
 L2 (6):     RETURN null

ext/opcache/tests/opt/sccp_010.phpt

@@ -32,6 +32,6 @@ L0 (15):    RETURN int(1)
 foo: ; (lines=3, args=0, vars=0, tmps=0)
     ; (after optimizer)
     ; %ssccp_010.php:2-13
-L0 (10):    ECHO int(1)
-L1 (12):    ECHO int(1)
+L0 (10):    ECHO string("1")
+L1 (12):    ECHO string("1")
 L2 (13):    RETURN null

ext/opcache/tests/opt/sccp_011.phpt

@@ -32,5 +32,5 @@ foo: ; (lines=3, args=1, vars=1, tmps=0)
     ; (after optimizer)
     ; %ssccp_011.php:2-12
 L0 (2):     CV0($x) = RECV 1
-L1 (11):    ECHO int(0)
+L1 (11):    ECHO string("0")
 L2 (12):    RETURN null

ext/opcache/tests/opt/sccp_012.phpt

@@ -34,6 +34,6 @@ L0 (17):    RETURN int(1)
 foo: ; (lines=3, args=0, vars=0, tmps=0)
     ; (after optimizer)
     ; %ssccp_012.php:2-15
-L0 (10):    ECHO int(1)
-L1 (14):    ECHO int(4)
+L0 (10):    ECHO string("1")
+L1 (14):    ECHO string("4")
 L2 (15):    RETURN null

ext/opcache/tests/opt/sccp_022.phpt

@@ -32,7 +32,7 @@ L1 (3):     ASSIGN_DIM CV1($a) int(0)
 L2 (3):     OP_DATA CV0($x)
 L3 (4):     ASSIGN_DIM CV1($a) int(1)
 L4 (4):     OP_DATA int(5)
-L5 (5):     ECHO int(5)
+L5 (5):     ECHO string("5")
 L6 (6):     ASSIGN_OBJ CV1($a) string("foo")
 L7 (6):     OP_DATA int(5)
 L8 (7):     T2 = FETCH_DIM_R CV1($a) int(1)

ext/opcache/tests/opt/sccp_031.phpt

@@ -0,0 +1,36 @@
+--TEST--
+SCCP 031: Echo optimizations
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+opcache.opt_debug_level=0x20000
+opcache.preload=
+--SKIPIF--
+<?php require_once('skipif.inc'); ?>
+--FILE--
+<?php
+function foo() {
+	$k = 0;
+	$a = [null];
+	echo isset($a[$k]);
+	echo "b";
+	echo isset($a[$k+1]);
+	echo "c";
+	echo $a[$k];
+	echo $a; // Should not be optimized
+}
+?>
+--EXPECTF--
+$_main: ; (lines=1, args=0, vars=0, tmps=0)
+    ; (after optimizer)
+    ; %ssccp_031.php:1-13
+L0 (13):    RETURN int(1)
+
+foo: ; (lines=4, args=0, vars=0, tmps=0)
+    ; (after optimizer)
+    ; %s_031.php:2-11
+L0 (6):     ECHO string("b")
+L1 (8):     ECHO string("c")
+L2 (10):    ECHO array(...)
+L3 (11):    RETURN null