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Re: "Values optmized out" and http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36303
- From: Ian Lance Taylor <iant at google dot com>
- To: Faraz Ahmed <faraz dot shaikh at gmail dot com>
- Cc: gcc-help at gcc dot gnu dot org
- Date: Tue, 31 Mar 2009 07:20:01 -0700
- Subject: Re: "Values optmized out" and http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36303
- References: <4ab9d9690903292238g43dd2f99ycbbb9a13772b4a3b@mail.gmail.com> <4ab9d9690903292242nb0035b5hb495d89aae9b3a7d@mail.gmail.com>
Faraz Ahmed <faraz.shaikh@gmail.com> writes:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36303
>
> In reference to the above bug, gcc optimized some code under the -O2
> option. If the assembly described in the bug is a standard behaviour
> of -O2 then one can close this bug. Can someone please confirm this to
> be a bug, or a valid -O2 optimization that won't be fixed.
There are known deficiencies in gcc's current location list
information. There are two independent projects under way to address
this:
http://gcc.gnu.org/wiki/Var_Tracking_Assignments
http://gcc.gnu.org/wiki/AndrewMacLeod (DEBUGLOCUS on that page)
With luck one of those will eventually be committed to mainline and will
address this issue.
Ian