JIT: Fix incorrect elimination of type store

Fixes oss-fuzz #41995

Author: dstogov

ext/opcache/jit/zend_jit.c

@@ -2341,7 +2341,9 @@ static int zend_jit(const zend_op_array *op_array, zend_ssa *ssa, const zend_op
 						if (opline->result_type != IS_UNUSED) {
 							res_use_info = -1;
 
-							if (opline->result_type == IS_CV) {
+							if (opline->result_type == IS_CV
+							 && ssa_op->result_use >= 0
+							 && !ssa->vars[ssa_op->result_use].no_val) {
 								zend_jit_addr res_use_addr = RES_USE_REG_ADDR();
 
 								if (Z_MODE(res_use_addr) != IS_REG
@@ -2403,7 +2405,9 @@ static int zend_jit(const zend_op_array *op_array, zend_ssa *ssa, const zend_op
 						} else {
 							res_use_info = -1;
 
-							if (opline->result_type == IS_CV) {
+							if (opline->result_type == IS_CV
+							 && ssa_op->result_use >= 0
+							 && !ssa->vars[ssa_op->result_use].no_val) {
 								zend_jit_addr res_use_addr = RES_USE_REG_ADDR();
 
 								if (Z_MODE(res_use_addr) != IS_REG
@@ -2458,7 +2462,9 @@ static int zend_jit(const zend_op_array *op_array, zend_ssa *ssa, const zend_op
 						} else {
 							res_use_info = -1;
 
-							if (opline->result_type == IS_CV) {
+							if (opline->result_type == IS_CV
+							 && ssa_op->result_use >= 0
+							 && !ssa->vars[ssa_op->result_use].no_val) {
 								zend_jit_addr res_use_addr = RES_USE_REG_ADDR();
 
 								if (Z_MODE(res_use_addr) != IS_REG

ext/opcache/tests/jit/mul_008.phpt

@@ -0,0 +1,26 @@
+--TEST--
+JIT MUL: 008 incorrect elimination of type store
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+opcache.protect_memory=1
+--SKIPIF--
+<?php if (PHP_INT_SIZE != 8) die("skip: 64-bit only"); ?>
+--FILE--
+<?php
+function foo(int $a){
+    $a=$a%10;
+    $a=$f=$a*(6158978401740);
+    $a=$f=$a*(261740);
+    $a%0;
+}
+foo(3);
+?>
+--EXPECTF--
+Fatal error: Uncaught DivisionByZeroError: Modulo by zero in %smul_008.php:6
+Stack trace:
+#0 %smul_008.php(8): foo(%d)
+#1 {main}
+  thrown in %smul_008.php on line 6