[PATCH, testsuite]: PR 58757: Check for FP denormal values without triggering denormal exceptions

Joseph S. Myers joseph@codesourcery.com
Tue Sep 23 18:20:00 GMT 2014


On Tue, 23 Sep 2014, Uros Bizjak wrote:

> On Tue, Sep 23, 2014 at 7:57 PM, Joseph S. Myers
> <joseph@codesourcery.com> wrote:
> 
> >> Attached patch avoids triggering denormal exceptions when FP insns are
> >> used to check for non-zero denormal values.
> >
> > But I thought the point of the test was to verify that the compiler's
> > understanding of existence of subnormal values was consistent with the
> > processor.  If the processor is in a mode supporting such values, the
> > exceptions should be masked.  That is, the present test should pass
> > unconditionally, if it doesn't pass that indicates a bug (which might be
> > appropriate for XFAILing).
> 
> Alpha needs special instruction mode to process denormals. Without
> this special mode the insn traps as soon as denormal value is
> processed.

Yes, but I thought the point of that PR was that unless -mieee was given 
to support such values, *_TRUE_MIN should be the same as *_MIN, reflecting 
that they aren't supported.  And so the failure is showing that this bug 
is present (and so XFAILing with a comment referring to the bug is 
appropriate, rather than changing the test to pass).

-- 
Joseph S. Myers
joseph@codesourcery.com



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