TDA4VM: why while(1){;} is compiled as an empty function by the compiler

Pengfei Yuan

Intellectual 290 points

Part Number: TDA4VM

Tool/software:

1.the compiler is ti-cgt-arm_20.2.5.LTS

2.why the code below doesn't work, while(1){;} is compiled as an empty function by the compiler?

static void loopTest(void)
{
while(1)
{
;
}
}

over 1 year ago

0 Karthikeyan S over 1 year ago

TI__Genius 13950 points

Hi,

Pengfei Yuan said:
2.why the code below doesn't work, while(1){;} is compiled as an empty function by the compiler?

I will investigate and get back to you on this.

Regards,

Karthik

0 George Mock over 1 year ago

TI__Guru**** 250340 points

The optimization part of the compiler can see that loop does nothing, so it removes it. Here is an alternative to consider ...

static void loopTest()
{
    __delay_cycles(~0);
}

While not strictly an infinite loop, it has nearly the same effect.

Thanks and regards,

-George

0 Pengfei Yuan over 1 year ago in reply to George Mock

Intellectual 290 points

thanks, by the way, Are there any compilation options I can use to tell the compiler not to optimize it ?

0 George Mock over 1 year ago in reply to Pengfei Yuan

TI__Guru**** 250340 points

If it practical, isolate the while (1) loop into a separate source file. Then build that file with --opt_level=off. If your code is organized as a CCS project, you can use File Specific Options.

Thanks and regards,

-George

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TDA4VM: why while(1){;} is compiled as an empty function by the compiler