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Re: Patch ping


On 11/16/2012 01:10 AM, Jakub Jelinek wrote:
> Hi!
> 
> - PR54921 invalidate sp in cselib on fp setter insn
>   http://gcc.gnu.org/ml/gcc-patches/2012-10/msg02035.html
>   (perhaps in light of PR54402 the single_succ (ENTRY_BLOCK_PTR)
>   from the patch should be nuked)

> +      rtx expr = find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX);
> +      if (expr)
> +	pat = XEXP (expr, 0);
> +      if (GET_CODE (pat) == SET
> +	  && SET_DEST (pat) == hard_frame_pointer_rtx)
> +	cselib_invalidate_rtx (stack_pointer_rtx);
> +      else if (GET_CODE (pat) == PARALLEL)

This is only one possible way that FP can be set.
The others are with CFA_DEF_CFA or CFA_ADJUST_CFA.

Given 

+      && frame_pointer_needed
+      && RTX_FRAME_RELATED_P (insn)

is there any reason to do more than

       && modified_in_p (hard_frame_pointer_rtx, insn)

?


r~


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