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Re: [dataflow patch] DCE const/pure calls


Paolo Bonzini wrote:
> This patch allows DCE to mark const or pure calls as eliminatable.
> Together with other patches, I can then get rid of libcall notes on
> i386 at least.
>
> Bootstrapped/regtested i686-pc-linux-gnu; ok for branch?
>
Paolo,

It is nice to see that you are back. 

This patch looks fine, however, i would like you to hold off on it for a
while.

I am about to commit a patch, that if it fixes certain issues that were
raised by Vlad, I will claim will complete the dataflow branch.  I then
plan to close the dataflow branch to further changes unless they remove
regressions or are suggested by reviewers. 

In particular, I need to stop the flow of minor improvements so that we
can concentrate on stability.

Kenny
> Paolo
> ------------------------------------------------------------------------
>
> 2007-05-08  Paolo Bonzini  <bonzini@gnu.org>
>
> 	* dce.c (deletable_insn_p): Const or pure calls are deletable.
>
> Index: dce.c
> ===================================================================
> --- dce.c	(revision 124539)
> +++ dce.c	(working copy)
> @@ -96,16 +96,16 @@ deletable_insn_p (rtx insn, bool fast)
>  	return false;
>  
>      default:
> -      if (!NONJUMP_INSN_P (insn))
> -	return false;
> -
>        if (volatile_insn_p (PATTERN (insn)))
>  	return false;
>  
>        if (flag_non_call_exceptions && may_trap_p (PATTERN (insn)))
>  	return false;
>  
> -      return true;
> +      if (CALL_P (insn) && CONST_OR_PURE_CALL_P (insn))
> +	return true;
> +
> +      return NONJUMP_INSN_P (insn);
>      }
>  }
>  
>   


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