Re: wide-int, rs6000

[Mike Stump]

On Nov 26, 2013, at 3:58 AM, Richard Sandiford <rsand...@linux.vnet.ibm.com> 
wrote:
> Mike Stump <mikest...@comcast.net> writes:
>> On Nov 25, 2013, at 12:03 PM, David Edelsohn <dje....@gmail.com> wrote:
>>> 3) altivec_resolve_overloaded_builtin, both hunks should be converted
>>> the same way, using tree_fits_uhwi_p
>>> 
>>> -   && TREE_CODE (arg2) == INTEGER_CST
>>> -   && TREE_INT_CST_HIGH (arg2) == 0
>>> -   && (TREE_INT_CST_LOW (arg2) == 0 || TREE_INT_CST_LOW (arg2) == 1))
>>> +   && tree_fits_uhwi_p (arg2)
>>> +   && wi::ltu_p (arg2, 2))
>> 
>> Index: gcc/config/rs6000/rs6000-c.c
>> ===================================================================
>> --- gcc/config/rs6000/rs6000-c.c     (revision 205364)
>> +++ gcc/config/rs6000/rs6000-c.c     (working copy)
>> @@ -4208,7 +4208,7 @@ altivec_resolve_overloaded_builtin (loca
>>       /* If we can use the VSX xxpermdi instruction, use that for extract.  
>> */
>>       mode = TYPE_MODE (arg1_type);
>>       if ((mode == V2DFmode || mode == V2DImode) && VECTOR_MEM_VSX_P (mode)
>> -      && TREE_CODE (arg2) == INTEGER_CST
>> +      && tree_fits_uhwi_p (arg2)
>>        && wi::ltu_p (arg2, 2))
>>      {
>>        tree call = NULL_TREE;
> 
> Hmm, I think the original was correct here, since there's no reason to rely
> on HWIness for an unsigned comparison with 2.  It also ought to be more
> efficient.
> 
> I'd rather change the other case to have an INTEGER_CST test too.

I agree, here is what I'm including to David for review…  Thanks.

Index: gcc/config/rs6000/rs6000-c.c
===================================================================
--- gcc/config/rs6000/rs6000-c.c        (revision 205414)
+++ gcc/config/rs6000/rs6000-c.c        (working copy)
@@ -4208,7 +4208,7 @@ altivec_resolve_overloaded_builtin (loca
       /* If we can use the VSX xxpermdi instruction, use that for extract.  */
       mode = TYPE_MODE (arg1_type);
       if ((mode == V2DFmode || mode == V2DImode) && VECTOR_MEM_VSX_P (mode)
-         && tree_fits_uhwi_p (arg2)
+         && TREE_CODE (arg2) == INTEGER_CST
          && wi::ltu_p (arg2, 2))
        {
          tree call = NULL_TREE;
@@ -4293,7 +4293,7 @@ altivec_resolve_overloaded_builtin (loca
       /* If we can use the VSX xxpermdi instruction, use that for insert.  */
       mode = TYPE_MODE (arg1_type);
       if ((mode == V2DFmode || mode == V2DImode) && VECTOR_UNIT_VSX_P (mode)
-         && tree_fits_uhwi_p (arg2)
+         && TREE_CODE (arg2) == INTEGER_CST
          && wi::ltu_p (arg2, 2))
        {
          tree call = NULL_TREE;