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[Bug c/63803] When GCC 4.9.2 compile with option -O2, the target is error.
- From: "ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 10 Nov 2014 11:18:46 +0000
- Subject: [Bug c/63803] When GCC 4.9.2 compile with option -O2, the target is error.
- Auto-submitted: auto-generated
- References: <bug-63803-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63803
ktkachov at gcc dot gnu.org changed:
What |Removed |Added
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CC| |ktkachov at gcc dot gnu.org
--- Comment #4 from ktkachov at gcc dot gnu.org ---
The problem here is that the code uses undefined behaviour according to the C
standard (dereferencing NULL pointer), therefore the compiler is free to do
whatever it wants. The user code should be fixed to not do that.
GCC 4.9 is free to change its behaviour from 4.8 in such code because it makes
(and shouldn't make) no guarantees about undefined behaviour