generating constant pool

generating constant pool

[Rajiv KI]

Hi gcc-help,

I have ported gcc on a dummy target to learn about gcc-porting. I referenced
'gccint' document and 'IIT' docs for porting. And i am finished with support
to single integer. All my desired operations are working fine.

Now to extend with and learn more i started double integer support. My
target size i fixed is 32bit. So to support double integer i want to
generate a constant pool. And for generating constant pool i read in gccint
doc it says to define TARGET_CANNOT_FORCE_CONST_MEM as TRUE. I tried that
but didn't get desired results. Help me to solve it out.

Regards,
Rajiv.
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Re: generating constant pool

[Ian Lance Taylor]

Rajiv KI <rajivkumarsingla@gmx.com> writes:

> Now to extend with and learn more i started double integer support. My
> target size i fixed is 32bit. So to support double integer i want to
> generate a constant pool. And for generating constant pool i read in gccint
> doc it says to define TARGET_CANNOT_FORCE_CONST_MEM as TRUE. I tried that
> but didn't get desired results. Help me to solve it out.

TARGET_CANNOT_FORCE_CONST_MEM should not be defined to be true for an
ordinary constant.  It should only return true for special cases like
the address of a TLS symbol.

gcc will automatically generate a constant pool when it sees a
constant which is not LEGITIMATE_CONSTANT_P.

Ian

Re: generating constant pool

[Rajiv KI]

Ya I tried in that way also. Means making double integer as
non-Legitimate_constant.

In my case legitimate_constant_p was looking like this:
int
legitimate_constant_p (rtx X)
{
        return (GET_CODE(X)!= CONST_DOUBLE);
}

But it was not generating constant pool when i assigned 64bit no. to a 'long
long' type variable. Rather It was doing all in '.main' function only.




Ian Lance Taylor-3 wrote:
> 
> Rajiv KI <rajivkumarsingla@gmx.com> writes:
> 
>> Now to extend with and learn more i started double integer support. My
>> target size i fixed is 32bit. So to support double integer i want to
>> generate a constant pool. And for generating constant pool i read in
>> gccint
>> doc it says to define TARGET_CANNOT_FORCE_CONST_MEM as TRUE. I tried that
>> but didn't get desired results. Help me to solve it out.
> 
> TARGET_CANNOT_FORCE_CONST_MEM should not be defined to be true for an
> ordinary constant.  It should only return true for special cases like
> the address of a TLS symbol.
> 
> gcc will automatically generate a constant pool when it sees a
> constant which is not LEGITIMATE_CONSTANT_P.
> 
> Ian
> 
> 

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