Tracing JIT: Fixed incorrect assumption about in-memeory zval type

Author: dstogov

ext/opcache/jit/zend_jit_trace.c

@@ -5924,7 +5924,8 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 					}
 					SET_STACK_TYPE(stack, EX_VAR_TO_NUM(opline->op1.var), type,
 						(type == IS_UNKNOWN || !ra ||
-							(!ra[ssa_op->op1_def] && !ssa->vars[ssa_op->op1_def].no_val)));
+							(!ra[ssa_op->op1_def] &&
+								(opline->opcode == ZEND_ASSIGN || !ssa->vars[ssa_op->op1_def].no_val))));
 					if (type != IS_UNKNOWN) {
 						ssa->var_info[ssa_op->op1_def].type &= ~MAY_BE_GUARD;
 						if (ra && ra[ssa_op->op1_def]) {

ext/opcache/tests/jit/assign_046.phpt

@@ -0,0 +1,38 @@
+--TEST--
+JIT ASSIGN: incorrect assumption about in-memeory zval type
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+opcache.protect_memory=1
+--FILE--
+<?php
+function test() {
+    $a = null;
+    for ($i = 0; $i < 6; $i++) {
+        var_dump($a);
+        $a = $a + $a = +$a = $b;
+    }
+}
+test();
+?>
+--EXPECTF--
+NULL
+
+Warning: Undefined variable $b in %sassign_046.php on line 6
+int(0)
+
+Warning: Undefined variable $b in %sassign_046.php on line 6
+int(0)
+
+Warning: Undefined variable $b in %sassign_046.php on line 6
+int(0)
+
+Warning: Undefined variable $b in %sassign_046.php on line 6
+int(0)
+
+Warning: Undefined variable $b in %sassign_046.php on line 6
+int(0)
+
+Warning: Undefined variable $b in %sassign_046.php on line 6