Check "ssa_op" before dereference (it may be NULL for opcache.jit=51)

Author: dstogov

ext/opcache/jit/zend_jit_trace.c

@@ -6656,6 +6656,7 @@ static const void *zend_jit_trace(zend_jit_trace_rec *trace_buffer, uint32_t par
 				 && (init_opline->opcode != ZEND_INIT_METHOD_CALL
 				  || init_opline->op1_type == IS_UNDEF
 				  || (!(p->info & ZEND_JIT_TRACE_FAKE_INIT_CALL)
+				   && ssa_op
 				   && (ssa_op-1)->op1_use >=0
 				   && ssa->var_info[(ssa_op-1)->op1_use].delayed_fetch_this))
 				 && (init_opline->opcode != ZEND_INIT_USER_CALL