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Re: wide-int branch now up for public comment and review


On Aug 25, 2013, at 11:29 AM, Richard Sandiford <rdsandiford@googlemail.com> wrote:
> Mike Stump <mikestump@comcast.net> writes:
>> On Aug 23, 2013, at 8:02 AM, Richard Sandiford
>> <rdsandiford@googlemail.com> wrote:
>>> We really need to get rid of the #include "tm.h" in wide-int.h.
>>> MAX_BITSIZE_MODE_ANY_INT should be the only partially-target-dependent
>>> thing in there.  If that comes from tm.h then perhaps we should put it
>>> into a new header file instead.
>> 
>> BITS_PER_UNIT comes from there as well, and I'd need both.  Grabbing the
>> #defines we generate is easy enough, but BITS_PER_UNIT would be more
>> annoying.  No port in the tree makes use of it yet (other than 8).  So,
>> do we just assume BITS_PER_UNIT is 8?
> 
> Looks like wide-int is just using BITS_PER_UNIT to get the number of
> bits in "char".  That's a host thing, so it should be CHAR_BIT instead.

?  What?  No.  BITS_PER_UNIT is a feature of the target machine, so, it is absolutely wrong to use a property of the host machine or the build machine.  We don't use sizeof(int) to set the size of int on the target for the example same reason.

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