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[Bug c/42179] Incorrect optimization (-O2) yields wrong code (regression)
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 26 Nov 2009 09:56:09 -0000
- Subject: [Bug c/42179] Incorrect optimization (-O2) yields wrong code (regression)
- References: <bug-42179-6373@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #1 from rguenth at gcc dot gnu dot org 2009-11-26 09:56 -------
Aliasing rules are indeed broken because you access a union of anonymous type
through a pointer to a union of type ieee_double_extract.
I think you want
union { union ieee_double_extract d; unsigned long long i; } x;
x.d.d = 0.0 / 0.0;
printf ("d = %g [%llx]\n", x.d.d, x.d.i);
printf ("exp = %x\n", (unsigned int) x.d.s.exp);
return 0;
or even simplified.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42179