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Re: [PATCH] gdb/i387-tdep.c: Avoid warning for "-Werror=strict-overflow"
- From: Pedro Alves <palves at redhat dot com>
- To: Joel Brobecker <brobecker at adacore dot com>, Chen Gang <gang dot chen dot 5i5j at gmail dot com>
- Cc: Mark Kettenis <mark dot kettenis at xs4all dot nl>, amodra at gmail dot com, gbenson at redhat dot com, michael dot sturm at intel dot com, walfred dot tedeschi at intel dot com, binutils at sourceware dot org, gdb-patches at sourceware dot org
- Date: Fri, 03 Oct 2014 18:49:51 +0100
- Subject: Re: [PATCH] gdb/i387-tdep.c: Avoid warning for "-Werror=strict-overflow"
- Authentication-results: sourceware.org; auth=none
- References: <542EC11C dot 3020406 at gmail dot com> <201410031546 dot s93FknOM002165 at glazunov dot sibelius dot xs4all dot nl> <542EC9FC dot 8050107 at gmail dot com> <20141003164420 dot GK6927 at adacore dot com>
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