Re: [PATCH] gdb/i387-tdep.c: Avoid warning for "-Werror=strict-overflow"

Walfred Tedeschi
2014-10-09T10:06:41Z

Am 10/3/2014 7:49 PM, schrieb Pedro Alves:
> On 10/03/2014 05:44 PM, Joel Brobecker wrote:
>>>> Sorry, but obfuscating code to make compilers happy is *not* the way to go.
>>>>
>>> OK, I can understand, but for me, these is no other better ways for it,
>>> except let gdb give up "-Werror" (if always need "--disable-werror"
>>> during "configure").
>> I have to agree with Mark on this one, the proposed solution looks
>> awful. There has to be another way. Maybe declaring a local constant
>> whose value is I387_XMM0_REGNUM (tdep)?
> Likely, after transformations and intra-procedural analyses, gcc would
> end up with the same.
>
> This:
>
> for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++)
>
> always iterates exactly 16 times, because I387_XMM0_REGNUM
> is defined like:
>
> #define I387_XMM0_REGNUM(tdep) (I387_ST0_REGNUM (tdep) + 16)
>
> An alternative I think might work would be to give that magic
> 16 constant a name, say:
>
> #define I387_NUM_ST_REGS 16
>
> and then do:
>
> for (i = 0; i < i < I387_NUM_ST_REGS; i++)
> {
> int r = I387_ST0_REGNUM (tdep) + i;
>
> ... use 'r' instead of 'i' ...
> }
>
> Thanks,
> Pedro Alves
>
Later on we have introduced the _END macros, as can be seen on i387-tdep.h.
Creating one or two of them migh be a good idea to homogeinize the way
we handle the registers.

This will finally also join together all ideas presented before in only one.

Using the end will then make

for (i = I387_ST0_REGNUM (tdep); i < I387_XMM0_REGNUM (tdep); i++)

to be

for (i = I387_ST0_REGNUM (tdep); i < I387_STEND_REGNUM (tdep); i++)

We also define the number of regs for every technology in that file.

Thanks and regards,
-Fred and Michael
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