JIT: Fix incorrect type store elimination

Fixes oss-fuzz #42388

Author: dstogov

ext/opcache/jit/zend_jit_trace.c

@@ -4609,15 +4609,13 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 						op2_info = OP2_INFO();
 						CHECK_OP2_TRACE_TYPE();
 						op1_info = OP1_INFO();
-						if (ssa->vars[ssa_op->op1_use].no_val) {
-							if ((op1_info & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_GUARD)) == MAY_BE_LONG
-							 || (op1_info & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_GUARD)) == MAY_BE_DOUBLE) {
-								if (STACK_MEM_TYPE(stack, EX_VAR_TO_NUM(opline->op1.var)) != IS_LONG
-								 && STACK_MEM_TYPE(stack, EX_VAR_TO_NUM(opline->op1.var)) != IS_DOUBLE) {
-									/* type may be not set */
-									op1_info |= MAY_BE_NULL;
-							    }
-							}
+						if ((op1_info & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_GUARD)) == MAY_BE_LONG
+						 || (op1_info & (MAY_BE_ANY|MAY_BE_UNDEF|MAY_BE_GUARD)) == MAY_BE_DOUBLE) {
+							if (STACK_MEM_TYPE(stack, EX_VAR_TO_NUM(opline->op1.var)) != IS_LONG
+							 && STACK_MEM_TYPE(stack, EX_VAR_TO_NUM(opline->op1.var)) != IS_DOUBLE) {
+								/* type may be not set */
+								op1_info |= MAY_BE_NULL;
+						    }
 						}
 						CHECK_OP1_TRACE_TYPE();
 						op1_def_info = OP1_DEF_INFO();

ext/opcache/tests/jit/assign_048.phpt

@@ -0,0 +1,43 @@
+--TEST--
+JIT ASSIGN: incorrect type store elimination
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+opcache.protect_memory=1
+opcache.optimization_level=0x7FFEBFFF
+--FILE--
+<?php
+function test(){
+    $j = 0;
+    for($i=0; $i<10; $i++) {
+        +$b = +$b = unserialize('');
+        $y[] = 4;
+        $a + ~$b = $j++;
+     }
+}
+test();
+?>
+DONE
+--EXPECTF--
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+
+Warning: Undefined variable $a in %sassign_048.php on line 7
+DONE