When compiling with Nios II SBT, the optimize option (-O2) causes it to stop working.

Sorry for the delay.

I have tried many things and as a result the simplest sample code is as follows.

* The following source is executable

```
#pragma GCC optimize ("O0")
static void SampleFunction( )
{
IORD_16DIRECT( 0x3400000 , 12 );
}
```

* On the other hand, the following source is not executable.
(Specifically, if you place a breakpoint on `IORD_16DIRECT` in the debugger and step through it after stopping, it will fail.)

````
static void SampleFunction( )
{
IORD_16DIRECT( 0x3400000 , 12 );
}
```

Since the entire compilation option is subject to -O2, -O0 is applied to the former source and -O2 to the latter source.

Is there any possible problem?