Fixed code generation for CMP

Fixes oss-fuzz #63569

Author: dstogov

ext/opcache/jit/zend_jit_ir.c

@@ -6952,6 +6952,10 @@ static int zend_jit_cmp(zend_jit_ctx   *jit,
 		} else {
 			ir_MERGE_N(n, end_inputs->refs);
 		}
+	} else if (smart_branch_opcode && !exit_addr) {
+		/* dead code */
+		_zend_jit_add_predecessor_ref(jit, target_label, jit->b, ir_END());
+		jit->b = -1;
 	}
 
 	return 1;

ext/opcache/tests/jit/cmp_009.phpt

@@ -0,0 +1,54 @@
+--TEST--
+JIT CMP: 009 Wrong code generation for dead compare
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+--FILE--
+<?php
+function test() {
+	$j = 0;
+    for ($i = 0; $i < 20; $j++) {
+    $a&=
+    $a = $a.+
+    $tojenthiss[$i = $v] = $s=
+    $tojenthiss[$i = $v] = $s=
+    $a&=
+    $b =
+    $b =
+    $a = $a.+
+$obj->prop =
+    $a = $a.+
+$obj->prop =
+    $a = $a.+
+    $Sojenthiss[$i = $v] = $s=
+    $x!= $a ?: $c;
+    $x!= $a ?: $c;
+    $x!= $a ?: $c;
+    $x!= $a ?: $c;
+    $aZ = $a;
+    $aZ = $a;
+    $aZ = $a;
+    $a = $a.+
+    $a = $a.+
+    $x!= $a ?: $c;
+    $aZ = $a;
+    $a = $a.+
+    $a = $a.+
+$obj->prop =
+    $a = $a.+
+    $Sojenthiss[$i = $v] = $s=
+    $x!= $a ?: $c;
+    $x!= $a ?: $c;
+    $aZ = $a;
+    }
+}
+@test();
+?>
+--EXPECTF--
+Fatal error: Uncaught Error: Attempt to assign property "prop" on null in %scmp_009.php:15
+Stack trace:
+#0 %scmp_009.php(39): test()
+#1 {main}
+  thrown in %scmp_009.php on line 15