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Re: Update x86 ulps for GCC 7 [committed]


On Sat, 24 Jun 2017, Markus Trippelsdorf wrote:

> On 2017.06.23 at 20:23 +0000, Joseph Myers wrote:
> > Testing with GCC 7 for 32-bit x86 showed some ulps differences,
> > presumably from variation in when values with excess precision get
> > spilled to the stack and so lose that precision.  This patch updates
> > the libm-test-ulps files accordingly.
> 
> For AMD Ryzen x86_64 I need an additional update:

Such updates should generally just be committed.  In this case (x86_64, 
not long double) I'm not clear why you'd have ulps variation between 
processors, since excess precision is irrelevant on x86_64 and the x87 
transcendental instructions would only be used for long double.  But it 
could be an fma issue, if $CC $CFLAGS defaults to generating fma 
instructions, as that can cause ulps variation across architectures.

-- 
Joseph S. Myers
joseph@codesourcery.com


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