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Re: [PATCH][testsuite] Abort on failure in gcc.dg/pr30957-1.c


On 20-02-15 10:42, Jakub Jelinek wrote:
On Fri, Feb 20, 2015 at 10:25:54AM +0100, Tom de Vries wrote:
this patch reverses the abort logic in pr30957-1.c, such that it aborts on
failure rather than on success.

That sounds really weird.  From the description it looks like it is a known bug
that we don't return -0.0.
If 0.0 is the right return value instead, I'd the test should be written as
if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != 1.0)
   abort ();
to make it clear you are expecting positive 0.


Updated patch accordingly. OK for stage1?

Thanks,
- Tom
2015-02-20  Tom de Vries  <tom@codesourcery.com>

	* gcc.dg/pr30957-1.c: Make pr30957-1.c pass rather xfail.
---
 gcc/testsuite/gcc.dg/pr30957-1.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/pr30957-1.c b/gcc/testsuite/gcc.dg/pr30957-1.c
index 65b98fa..0ed150d 100644
--- a/gcc/testsuite/gcc.dg/pr30957-1.c
+++ b/gcc/testsuite/gcc.dg/pr30957-1.c
@@ -1,10 +1,6 @@
-/* { dg-do run { xfail *-*-* } } */
-/* We don't (and don't want to) perform this optimisation on soft-float
-   targets, where each addition is a library call.  This test requires
-   -fassociative-math for enabling the variable-expansion as well as
-   -fsigned-zeros for honoring the sign of zero; but
-   they can not co-exist; also under -funsafe-math-optimizations, so we
-   expect it to fail.  */
+/* { dg-do run } */
+/* We don't (and don't want to) perform this optimisation on soft-float targets,
+   where each addition is a library call.  /
 /* { dg-require-effective-target hard_float } */
 /* { dg-options "-O2 -funroll-loops -funsafe-math-optimizations -fvariable-expansion-in-unroller -fdump-rtl-loop2_unroll" } */
 
@@ -26,12 +22,14 @@ foo (float d, int n)
 int
 main ()
 {
-  if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != -1.0)
+  /* When compiling standard compliant we expect foo to return -0.0.  But the
+     variable expansion during unrolling optimization (for this testcase enabled
+     by -funsafe-math-optimization) instantiates copy(s) of the accumulator
+     which it initializes with +0.0.  Hence we expect that foo returns +0.0.  */
+  if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != 1.0)
     abort ();
   exit (0);
 }
 
 /* { dg-final { scan-rtl-dump "Expanding Accumulator" "loop2_unroll" } } */
 /* { dg-final { cleanup-rtl-dump "loop*" } } */
-
-
-- 
1.9.1


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