XFAILing gcc.dg/uninit-C.c on non 64-bit platforms?

[Jim Wilson]

Roger Sayle wrote:
> The question is therefore what is the correct way to limit this
> test to platforms that support __attribute__ ((mode (TI))?

There is an easy way that is almost completely correct.  Add ifdefs for 
__LP64__.  This is defined for all 64-bit targets with 64-bit longs and 
pointers.  As far as I know, that is all of the current 64-bit targets. 
  However, 64-bit windows is P64, so it wouldn't work there, but we 
don't have support for this target yet.

TImode exists if HOST_BITS_PER_WIDE_INT is 64 or more.  That would be 
the correct test.  There is no way to test for this in the testsuite 
without adding a new builtin macro, and it seems silly to add one just 
for a single testcase in the testsuite.

Jim