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[Bug tree-optimization/46693] incorrect code generation with -O2 optimization enabled
- From: "ramana at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 14 Dec 2010 09:28:21 +0000
- Subject: [Bug tree-optimization/46693] incorrect code generation with -O2 optimization enabled
- Auto-submitted: auto-generated
- References: <bug-46693-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46693
Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |NEW
Known to work| |4.3.5, 4.4.6
Known to fail| |4.5.1
--- Comment #11 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> 2010-12-14 09:27:58 UTC ---
So the problem on trunk atleast seems to be in gimple-fold
maybe_fold_or_comparisons and friends where all the comparisons are folded out
into a single boolean node of 1 where ideally the result of the basic block
should be reduced to the (c <= 31) && (x != 9) check . The other 2 equality
comparisons are superfluous.
I won't be able to look at this for a couple of days - hence unassigning
myself.
The problem for this file goes away with -fno-tree-vrp but that's a heavy
weight work around.
cheers
Ramana