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* [libffi testsuite] Set -ffp-contract=off for libffi.call/many.c
@ 2013-04-08  9:37 James Greenhalgh
  2013-04-19 10:01 ` James Greenhalgh
       [not found] ` <CACxje5_Tp0an2rRwyUWKsqdE9vMOwDxfkSgGYTiankAH0bQLFQ@mail.gmail.com>
  0 siblings, 2 replies; 5+ messages in thread
From: James Greenhalgh @ 2013-04-08  9:37 UTC (permalink / raw)
  To: libffi-discuss

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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.

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diff --git a/testsuite/libffi.call/many.c b/testsuite/libffi.call/many.c
index 67a367f..afade91 100644
--- a/testsuite/libffi.call/many.c
+++ b/testsuite/libffi.call/many.c
@@ -5,6 +5,8 @@
    Originator:	From the original ffitest.c  */
 
 /* { dg-do run } */
+/* { dg-options -ffp-contract=off } */
+
 #include "ffitest.h"
 
 #include <stdlib.h>

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2013-06-25 12:55 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-04-08  9:37 [libffi testsuite] Set -ffp-contract=off for libffi.call/many.c James Greenhalgh
2013-04-19 10:01 ` James Greenhalgh
2013-05-09 12:59   ` James Greenhalgh
     [not found] ` <CACxje5_Tp0an2rRwyUWKsqdE9vMOwDxfkSgGYTiankAH0bQLFQ@mail.gmail.com>
2013-05-29  8:39   ` James Greenhalgh
2013-06-25 12:55     ` James Greenhalgh

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