----- Message d'origine ----
De : Andrew Haley <aph@xxxxxxxxxx>
À : gcc-help@xxxxxxxxxxx
Envoyé le : Mar 19 avril 2011, 18h 53min 58s
Objet : Re: OR in Generic or Gimple
On 04/19/2011 05:48 PM, charfi asma wrote:
> Hello,
> In my front end I would like to translate to generic the OR operation (if ( y
> =a) || (y=b)) ...
> I tried to look at the gimple generated from this C++ program
>
> int main()
> {
> int x=6;
> int y = x+10;
> if ((y == 1) || (y==0))
> return 10;
> else
> return 0;
> }
>
>
> I found this:
>
>
> int main() ()
> {
> unsigned int y.0;
> unsigned int D.2070;
> int D.2073;
>
> {
> int x;
> int y;
>
> x = 6;
> y = x + 10;
> y.0 = (unsigned int) y;
> D.2070 = y.0 + 4294967295;
> if (D.2070 <= 1) goto <D.2071>; else goto <D.2072>;
> <D.2071>:
> D.2073 = 10;
> return D.2073;
> <D.2072>:
> D.2073 = 0;
> return D.2073;
> }
> D.2073 = 0;
> return D.2073;
> }
>
> I do not really understand how gimple is generated for the OR test.
I don't understand it either. I think it's a bug. I get:
int main() ()
{
unsigned int y.0;
int D.2099;
{
int x;
int y;
x = 6;
y = x + 10;
y.0 = (unsigned int) y;
if (y.0 <= 1) goto <D.2097>; else goto <D.2098>;
<D.2097>:
D.2099 = 10;
return D.2099;
<D.2098>:
D.2099 = 0;
return D.2099;
}
D.2099 = 0;
return D.2099;
}
Andrew.
Hello Andrew,
I get this using both gcc4.4.1 and gcc4.6.
I even tried with gcc (compile c file) instead of g++ (compile c++ file), but I
get the same gimple.
however when I change values:
int x=6;
int y =x+10;
if ((y > 1) || (y < 9)) ....
I get this:
int main() ()
{
int D.2071;
{
int x;
int y;
x = 6;
y = x + 10;
if (1 != 0) goto <D.2069>; else goto <D.2070>;
<D.2069>:
D.2071 = 10;
return D.2071;
<D.2070>:
D.2071 = 0;
return D.2071;
}
D.2071 = 0;
return D.2071;
}
Any way, did so know which generic tree code or gimple statement used to
generate this ? why if ((y > 1) || (y < 9)) is translated to if (1!=0) ??
thank you very much
Asma
