Merge branch 'PHP-8.1'

* PHP-8.1:
  Fix incorrect optimization that leads to memory leak

Author: dstogov

Zend/Optimizer/sccp.c

@@ -2244,6 +2244,17 @@ static int try_remove_definition(sccp_ctx *ctx, int var_num, zend_ssa_var *var,
 				zend_ssa_remove_result_def(ssa, ssa_op);
 				if (opline->opcode == ZEND_DO_ICALL) {
 					removed_ops = remove_call(ctx, opline, ssa_op);
+				} else if (opline->opcode == ZEND_TYPE_CHECK
+						&& (opline->op1_type & (IS_VAR|IS_TMP_VAR))
+						&& (!value_known(&ctx->values[ssa_op->op1_use])
+							|| IS_PARTIAL_ARRAY(&ctx->values[ssa_op->op1_use])
+							|| IS_PARTIAL_OBJECT(&ctx->values[ssa_op->op1_use]))) {
+					/* For TYPE_CHECK we may compute the result value without knowing the
+					 * operand, based on type inference information. Make sure the operand is
+					 * freed and leave further cleanup to DCE. */
+					opline->opcode = ZEND_FREE;
+					opline->result_type = IS_UNUSED;
+					removed_ops++;
 				} else {
 					zend_ssa_remove_instr(ssa, opline, ssa_op);
 					removed_ops++;

ext/opcache/tests/opt/sccp_034.phpt

@@ -0,0 +1,16 @@
+--TEST--
+SCCP 034: memory leak
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.optimization_level=-1
+--FILE--
+<?php
+is_array(["$y $y"]);
+?>
+DONE
+--EXPECTF--
+Warning: Undefined variable $y in %ssccp_034.php on line 2
+
+Warning: Undefined variable $y in %ssccp_034.php on line 2
+DONE