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[Bug rtl-optimization/23369] [4.0.x regression] Generates wrong code for funcptr comparison
- From: "tausq at debian dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 13 Aug 2005 03:08:07 -0000
- Subject: [Bug rtl-optimization/23369] [4.0.x regression] Generates wrong code for funcptr comparison
- References: <20050813025029.23369.tausq@debian.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From tausq at debian dot org 2005-08-13 03:08 -------
The line of code in question is:
51 if (old == SIG_IGN || old == SIG_DFL || old == SIG_ERR)
after preprocessing, this becomes
if (old == ((__sighandler_t) 1) || old == ((__sighandler_t) 0) || old
== ((__sighandler_t) -1))
It appears gcc optimized out the the old == 0 case, and it does the right thing
for the old == 1 case. For the old == -1 case, it seems to subtract 2 from old,
and converts -1 to -4.
Weird.
This also happens with -O1. Dave says it looks like the initial rtl generation
is wrong, so maybe this is not an optimization bug.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23369