Re: patch to fix constant math - first small patch - patch ping for the next stage 1

[Richard Biener <richard dot guenther at gmail dot com>]

On Wed, Apr 3, 2013 at 12:47 PM, Kenneth Zadeck
<zadeck@naturalbridge.com> wrote:
> yes, i had caught that when i merged it in with the patches that used it, is
> it ok aside from that?

Yes.

Thanks,
Richard.

> kenny
>
> On 04/03/2013 05:32 AM, Richard Biener wrote:
>>
>> On Tue, Apr 2, 2013 at 9:08 PM, Kenneth Zadeck <zadeck@naturalbridge.com>
>> wrote:
>>>
>>> this time for sure.
>>
>> Almost ...
>>
>> diff --git a/gcc/hwint.c b/gcc/hwint.c
>> index 330b42c..92d54a3 100644
>> --- a/gcc/hwint.c
>> +++ b/gcc/hwint.c
>> @@ -204,3 +204,35 @@ least_common_multiple (HOST_WIDE_INT a, HOST_WIDE_INT
>> b)
>>   {
>>     return mul_hwi (abs_hwi (a) / gcd (a, b), abs_hwi (b));
>>   }
>> +
>> +#ifndef ENABLE_CHECKING
>>
>> #ifdef ENABLE_CHECKING
>>
>> +/* Sign extend SRC starting from PREC.  */
>> +
>> +HOST_WIDE_INT
>> +sext_hwi (HOST_WIDE_INT src, unsigned int prec)
>> +{
>> +  gcc_checking_assert (prec <= HOST_BITS_PER_WIDE_INT);
>> +
>>
>> Ok with that change.  (maybe catch one random use of the pattern
>> in code and use the helpers - that would have catched this issue)
>>
>> Thanks,
>> Richard.
>>
>>
>>
>>> kenny
>>>
>>> On 04/02/2013 10:54 AM, Richard Biener wrote:
>>>>
>>>> On Tue, Apr 2, 2013 at 3:49 PM, Kenneth Zadeck
>>>> <zadeck@naturalbridge.com>
>>>> wrote:
>>>>>
>>>>> Richard,
>>>>>
>>>>> did everything that you asked here.  bootstrapped and regtested on
>>>>> x86-64.
>>>>> ok to commit?
>>>>
>>>> diff --git a/gcc/hwint.c b/gcc/hwint.c
>>>> index 330b42c..7e5b85c 100644
>>>> --- a/gcc/hwint.c
>>>> +++ b/gcc/hwint.c
>>>> @@ -204,3 +204,33 @@ least_common_multiple (HOST_WIDE_INT a,
>>>> HOST_WIDE_INT
>>>> b)
>>>>    {
>>>>      return mul_hwi (abs_hwi (a) / gcd (a, b), abs_hwi (b));
>>>>    }
>>>> +
>>>> +#ifndef ENABLE_CHECKING
>>>> +/* Sign extend SRC starting from PREC.  */
>>>> +
>>>> +HOST_WIDE_INT
>>>> +sext_hwi (HOST_WIDE_INT src, unsigned int prec)
>>>>
>>>> this should go to hwint.h, and without the masking of prec.
>>>> while ...
>>>>
>>>> diff --git a/gcc/hwint.h b/gcc/hwint.h
>>>> index da62fad..9dddf05 100644
>>>> --- a/gcc/hwint.h
>>>> +++ b/gcc/hwint.h
>>>> @@ -276,4 +316,42 @@ extern HOST_WIDE_INT pos_mul_hwi (HOST_WIDE_INT,
>>>> HOST_WIDE_INT);
>>>>    extern HOST_WIDE_INT mul_hwi (HOST_WIDE_INT, HOST_WIDE_INT);
>>>>    extern HOST_WIDE_INT least_common_multiple (HOST_WIDE_INT,
>>>> HOST_WIDE_INT);
>>>>
>>>> +/* Sign extend SRC starting from PREC.  */
>>>> +
>>>> +#ifdef ENABLE_CHECKING
>>>> +extern HOST_WIDE_INT sext_hwi (HOST_WIDE_INT, unsigned int);
>>>> +#else
>>>> +static inline HOST_WIDE_INT
>>>> +sext_hwi (HOST_WIDE_INT src, unsigned int prec)
>>>> +{
>>>> +  gcc_checking_assert (prec <= HOST_BITS_PER_WIDE_INT);
>>>>
>>>> this should go to hwint.c (also without masking prec).
>>>>
>>>> Richard.
>>>>
>>>>
>>>>
>>>>
>>>>> kenny
>>>>>
>>>>>
>>>>> On 04/02/2013 05:38 AM, Richard Biener wrote:
>>>>>>
>>>>>> On Sun, Mar 31, 2013 at 7:51 PM, Kenneth Zadeck
>>>>>> <zadeck@naturalbridge.com> wrote:
>>>>>>>
>>>>>>> richard,
>>>>>>>
>>>>>>> I was able to add everything except for the checking asserts.
>>>>>>> While
>>>>>>> I
>>>>>>> think that this is a reasonable idea, it is difficult to add that to
>>>>>>> a
>>>>>>> function that is defined in hwint.h because of circular includes.   I
>>>>>>> could
>>>>>>> move this another file (though this appears to be the logical correct
>>>>>>> place
>>>>>>> for it), or we can do without the asserts.
>>>>>>>
>>>>>>> The context is that [sz]ext_hwi is that are used are over the
>>>>>>> compiler
>>>>>>> but
>>>>>>> are generally written out long.   The wide-int class uses them also,
>>>>>>> but
>>>>>>> wide-int did not see like the right place for them to live and i
>>>>>>> believe
>>>>>>> that you suggested that i move them.
>>>>>>>
>>>>>>> ok to commit, or do you have a suggested resolution to the assert
>>>>>>> issue?
>>>>>>
>>>>>> Yes, do
>>>>>>
>>>>>> #ifdef ENABLE_CHECKING
>>>>>> extern HOST_WIDE_INT sext_hwi (HOST_WIDE_INT, unsigned int);
>>>>>> #else
>>>>>> +/* Sign extend SRC starting from PREC.  */
>>>>>> +
>>>>>> +static inline HOST_WIDE_INT
>>>>>> +sext_hwi (HOST_WIDE_INT src, unsigned int prec)
>>>>>> +{
>>>>>> +  if (prec == HOST_BITS_PER_WIDE_INT)
>>>>>> +    return src;
>>>>>> +  else
>>>>>> +    {
>>>>>>            int shift = HOST_BITS_PER_WIDE_INT - prec;
>>>>>> +      return (src << shift) >> shift;
>>>>>> +    }
>>>>>> +}
>>>>>> #endif
>>>>>>
>>>>>> and for ENABLE_CHECKING only provide an out-of-line implementation
>>>>>> in hwint.c.  That's how we did it with abs_hwi (well, we just do not
>>>>>> provide
>>>>>> an inline variant there - that's another possibility).
>>>>>>
>>>>>> Note that hwint.h is always included after config.h so the
>>>>>> ENABLE_CHECKING
>>>>>> definition should be available.
>>>>>>
>>>>>> Richard.
>>>>>>
>>>>>>> kenny
>>>>>>>
>>>>>>>
>>>>>>> On 03/27/2013 10:13 AM, Richard Biener wrote:
>>>>>>>>
>>>>>>>> On Wed, Feb 27, 2013 at 1:22 AM, Kenneth Zadeck
>>>>>>>> <zadeck@naturalbridge.com> wrote:
>>>>>>>>>
>>>>>>>>> Here is the first of my wide int patches with joseph's comments and
>>>>>>>>> the
>>>>>>>>> patch rot removed.
>>>>>>>>>
>>>>>>>>> I would like to get these pre approved for the next stage 1.
>>>>>>>>
>>>>>>>> +      int shift = HOST_BITS_PER_WIDE_INT - (prec &
>>>>>>>> (HOST_BITS_PER_WIDE_INT - 1));
>>>>>>>>
>>>>>>>> I think this should gcc_checking_assert that prec is not out of
>>>>>>>> range
>>>>>>>> (any reason why prec is signed int and not unsigned int?) rather
>>>>>>>> than
>>>>>>>> ignore bits in prec.
>>>>>>>>
>>>>>>>> +static inline HOST_WIDE_INT
>>>>>>>> +zext_hwi (HOST_WIDE_INT src, int prec)
>>>>>>>> +{
>>>>>>>> +  if (prec == HOST_BITS_PER_WIDE_INT)
>>>>>>>> +    return src;
>>>>>>>> +  else
>>>>>>>> +    return src & (((HOST_WIDE_INT)1
>>>>>>>> +                  << (prec & (HOST_BITS_PER_WIDE_INT - 1))) - 1);
>>>>>>>> +}
>>>>>>>>
>>>>>>>> likewise.  Also I'm not sure I agree about the signedness of the
>>>>>>>> result
>>>>>>>> /
>>>>>>>> src.
>>>>>>>> zext_hwi (-1, HOST_BITS_PER_WIDE_INT) < 0 is true which is odd.
>>>>>>>>
>>>>>>>> The patch misses context of uses, so I'm not sure what the above
>>>>>>>> functions
>>>>>>>> are intended to do.
>>>>>>>>
>>>>>>>> Richard.
>>>>>>>>
>>>>>>>>> On 10/05/2012 08:14 PM, Joseph S. Myers wrote:
>>>>>>>>>>
>>>>>>>>>> On Fri, 5 Oct 2012, Kenneth Zadeck wrote:
>>>>>>>>>>
>>>>>>>>>>> +# define HOST_HALF_WIDE_INT_PRINT "h"
>>>>>>>>>>
>>>>>>>>>> This may cause problems on hosts not supporting %hd (MinGW?), and
>>>>>>>>>> there's
>>>>>>>>>> no real need for using "h" here given the promotion of short to
>>>>>>>>>> int;
>>>>>>>>>> you
>>>>>>>>>> can just use "" (rather than e.g. needing special handling in
>>>>>>>>>> xm-mingw32.h
>>>>>>>>>> like is done for HOST_LONG_LONG_FORMAT).
>>>>>>>>>>
>