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[Bug tree-optimization/15353] [tree-ssa] Merge two "if"s if one subsumes the other.
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 11 Aug 2005 15:43:40 -0000
- Subject: [Bug tree-optimization/15353] [tree-ssa] Merge two "if"s if one subsumes the other.
- References: <20040509200719.15353.kazu@gcc.gnu.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From law at redhat dot com 2005-08-11 15:43 -------
Subject: Re: [tree-ssa] Merge two "if"s if
one subsumes the other.
On Thu, 2005-08-11 at 11:01 +0000, rguenth at gcc dot gnu dot org wrote:
> ------- Additional Comments From rguenth at gcc dot gnu dot org 2005-08-11 11:01 -------
> Couldn't DOM do this at jump threading time? I.e.
>
> if (D.1286_3 > D.1287_5) goto <L3>; else goto <L1>;
>
> <L1>:;
> if (D.1286_3 == D.1287_5) goto <L3>; else goto <L2>;
>
> during trying of threading through the jump at L1 merge the
> two conditionals?
Jump threading isn't particularly well suited for this kind of
optimization.
jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15353