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Re: Fix PR optimization/11753 (SPARC)
- From: "Zack Weinberg" <zack at codesourcery dot com>
- To: Eric Botcazou <ebotcazou at libertysurf dot fr>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Fri, 12 Sep 2003 15:32:06 -0700
- Subject: Re: Fix PR optimization/11753 (SPARC)
- References: <200309122340.45561.ebotcazou@libertysurf.fr>
Eric Botcazou <ebotcazou@libertysurf.fr> writes:
> Hi,
>
> This PR was reported against GCC 3.2.2, which emits in the middle of the
> assembly file generated for a big proprietary testcase:
>
> mov 1, %i0
> call free, 0
> add %o7, (.LL1-.-4), %o7
>
> This clever trick is intended to perfom a 'call' followed by a
>'jump' to .LL1 and is devised by an old-fashioned peephole:
[...]
Is this optimization even a good idea on modern Sparc hardware? It
seems like the sort of thing that would confuse a branch predictor.
zw