RE: [libffi testsuite] Set -ffp-contract=off for libffi.call/many.c

["James Greenhalgh" <james.greenhalgh@arm.com>]

*ping*

> -----Original Message-----
> From: James Greenhalgh
> Sent: 08 April 2013 10:37
> To: libffi-discuss@sourceware.org
> Subject: [libffi testsuite] Set -ffp-contract=off for
> libffi.call/many.c
> 
> 
> Hi,
> 
> A recent patch fixed libffi.call/many.c to check that the absolute
> value of the difference of its two test results was smaller than
> FLT_EPSILON,
> rather than just checking their difference.
> 
> Sadly, this exposes a problem with the testcase for targets with
> a fused-multiply-add instruction. After inlining the non-ffi function
> body, GCC will happily contract the final multiply with the subtract
> for the comparison. Thus skipping the rounding step after the multiply
> and causing an error large enough to cause the test to fail.
> 
> Fixed by adding -ffp-contract=off to the list of dg-options thus
> suppressing the introduction of fused-multiply-add.
> 
> Tested on aarch64-none-linux-gnu to ensure the failure becomes
> a pass.
> 
> Thanks,
> James Greenhalgh
> 
> ---
> 
> 2013-04-08  James Greenhalgh  <james.greenhalgh@arm.com>
> 
> 	* testsuite/libffi.call/many.c: Set -ffp-contract=off.