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[Bug optimization/2806] if's are not combined together
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 4 Mar 2004 05:00:37 -0000
- Subject: [Bug optimization/2806] if's are not combined together
- References: <20010511150601.2806.eric-gcc@omnifarious.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From law at redhat dot com 2004-03-04 05:00 -------
Subject: Re: if's are not combined together
In message <20040304030605.4965.qmail@sources.redhat.com>, "pinskia at gcc dot
gnu dot org" writes:
>
>------- Additional Comments From pinskia at gcc dot gnu dot org 2004-03-04 0
>3:06 -------
>We are now missing one jump threading for some reason:
>(From .DOM3):
>{
><bb 0>:
> if (eax_1 == 65535) goto <L0>; else goto <L6>;
>
><L0>:;
> if (edx_2 == 1) goto <L1>; else goto <L4>;
>
><L1>:;
> abarney[0] = 5;
> abarney[1] = 6;
>
><L4>:;
> edx_3 = edx_2 - 1;
> if (edx_3 == 0) goto <L5>; else goto <L6>;
>
><L5>:;
> afred[0] = 2;
>
><L6>:;
> return;
What jump do you think should be threaded? I don't see any jump threading
opportunities here -- at least not without knowing that edx_3 is only used
once.
jeff
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=2806