[Bug tree-optimization/15089] [3.4/3.5 Regression] [tree-ssa] local register variable with a specified register is bad
mark at codesourcery dot com
gcc-bugzilla@gcc.gnu.org
Wed Jun 23 22:11:00 GMT 2004
------- Additional Comments From mark at codesourcery dot com 2004-06-23 22:08 -------
Subject: Re: [3.4/3.5 Regression] [tree-ssa]
local register variable with a specified register is bad
Ian Lance Taylor wrote:
> "mmitchel at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:
>
>
>>When __l is used in the asm, the writer of the bugzilla report expects
>>to see register "r0". However, the value happens to be hanging around
>>in a different register so GCC uses that other register instead of
>>"r0". Similarly for uses of __i. The behavior of the compiler is
>>precisely what I would expect."
>
>
> But what about this comment from RTH?
> http://gcc.gnu.org/ml/gcc/2004-05/msg00657.html
>
> He is describing what appears to me to be an undocumented feature, but
> one which he says is important.
I don't know; I don't have enough experience with these kinds of tricks.
(When I need to do these kinds of things, I just write assembly code.)
If Richard and Jeff agree to reopen the bug, that's fine with me.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15089
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