Compiler problem in Keil 5.24.2.0

[chianglin]

Hi,

Please find following source code.

		if ( MotorDirection == 1 )
		{
			NRF_LOG_INFO(" Motor Forword");
			nrf_gpio_pin_write(MotorDirectionControl, 1);									// 馬達往前
		}
		else if ( MotorDirection == -1 )
		{
			NRF_LOG_INFO(" Motor Backword");
			nrf_gpio_pin_write(MotorDirectionControl, 0);									// 馬達往後
		}
		else
		{
			NRF_LOG_INFO(" Motor Stop");
			nrf_gpio_pin_write(MotorDirectionControl, 1);
		}

After compiler by Keil 5.24.2, some code will not compiled,

I can see the situation by "enter debug mode, please find following image.

Would you please tell me why?

Thank you

[ovrebekk]

Hi Ives

It seems the compiler expects the MotorDirection variable never to be set to -1. 

Could it be that it is defined as unsigned, or that you never set it to -1?

Possibly it should be declared as volatile, if you write to it from an interrupt handler. 

Best regards
Torbjørn

[chianglin]

Hi Torbjørn,

Thank you for your explain.

It looks the compiler is very smart, so it will ignore some which may not be execute.

Can I disable this compile option, so all of my source can compile to binary?

Thank you,

Chianglin

[ovrebekk]

Hi Chianglin

You should be able to turn of code optimization in the compiler settings. By default it is set to level 3, which does a lot of optimizations, but you can turn it off completely. 

Can you try to change this and see if it solves the problem?

Best regards
Torbjørn