• Matheus (21/21) Oct 09 2021 I saw this problem in C, then I tried on GDC and have the same
• Iain Buclaw (4/24) Oct 09 2021 Nothing I can really do about that, it's occurring outside of the

Matheus <matheus gmail.com> writes:

I saw this problem in C, then I tried on GDC and have the same 
problem:

int main() {
    for (uint a = 0, b = 0; a < 6; a += 1, b += 2){
         if (b < a){
             return 1;
         }
    }
    return 0;
}

The code above generates the wrong code when using: -O1, -O2 or 
-O3:

_Dmain:
         mov     eax, 1
         ret

Changing "uint" to "int" will that, or initializing with both "a" 
and "b" with a different value like "1" instead of "0" will work 
in -01, but will keep failing for -02 or -03.

Finally initializing with negative number will work for all 3 
optimization level.

Matheus.

Iain Buclaw <ibuclaw gdcproject.org> writes:

On Saturday, 9 October 2021 at 14:52:47 UTC, Matheus wrote:
 I saw this problem in C, then I tried on GDC and have the same 
 problem:

 int main() {
    for (uint a = 0, b = 0; a < 6; a += 1, b += 2){
         if (b < a){
             return 1;
         }
    }
    return 0;
 }

 The code above generates the wrong code when using: -O1, -O2 or 
 -O3:

 _Dmain:
         mov     eax, 1
         ret

 Changing "uint" to "int" will that, or initializing with both 
 "a" and "b" with a different value like "1" instead of "0" will 
 work in -01, but will keep failing for -02 or -03.

 Finally initializing with negative number will work for all 3 
 optimization level.

Nothing I can really do about that, it's occurring outside of the 
D front-end.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100740