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[Bug target/24419] ix86 prologue clobbers memory when it shouldn't
- From: "jh at suse dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 18 Oct 2005 18:29:43 -0000
- Subject: [Bug target/24419] ix86 prologue clobbers memory when it shouldn't
- References: <bug-24419-682@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #13 from jh at suse dot cz 2005-10-18 18:29 -------
Subject: Re: ix86 prologue clobbers memory when it shouldn't
>
>
> ------- Comment #12 from hjl at lucon dot org 2005-10-18 18:26 -------
> There is another issue when converting stack additions to pop:
>
> (define_peephole2
> [(match_scratch:SI 0 "r")
> (parallel [(set (reg:SI SP_REG) (plus:SI (reg:SI SP_REG) (const_int 4)))
> (clobber (reg:CC FLAGS_REG))])]
> ""
> [(parallel [(set (match_dup 0) (mem:SI (reg:SI SP_REG)))
> (set (reg:SI SP_REG) (plus:SI (reg:SI SP_REG) (const_int 4)))])]
> "")
>
> Is that 100% safe with red zone? In theory, compiler can adjust stack, but not
> clobber memory since there is a red zone.
It is reading memory here, not writting so it should be safe...
Honza
>
>
> --
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24419
>
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24419