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[Bug middle-end/33794] [4.3 regression] Wrong code w/ -ffast-math
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 17 Oct 2007 12:28:13 -0000
- Subject: [Bug middle-end/33794] [4.3 regression] Wrong code w/ -ffast-math
- References: <bug-33794-13404@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from ubizjak at gmail dot com 2007-10-17 12:28 -------
(In reply to comment #9)
I don't want to claim excess precision problems here. I was trying to debug
self_ind_cir_coil procedure, as it looks that the problem is in calculation of
self_r output.
The input to this procedure is always the same:
2.99999999999999989E-002
3.00000000000000006E-003
166666.66666666666
1.25663706143591729E-006
but for -O2 -ffast-math -ffloat-store, self_l is returned as
self_l 3.66008420600437631E-002
and for -O2 -ffast-math, self_l is returned as (wrong):
self_l 8.51113565610957021E-008
I don't see why the code in between would produce such wildly different result.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33794