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Re: [PATCH, PR58066] preferred_stack_boundary update for tls expanded call
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Wei Mi <wmi at google dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, David Li <davidxl at google dot com>, Uros Bizjak <ubizjak at gmail dot com>
- Date: Wed, 12 Mar 2014 14:42:36 -0700
- Subject: Re: [PATCH, PR58066] preferred_stack_boundary update for tls expanded call
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On Wed, Mar 12, 2014 at 2:36 PM, Wei Mi <wmi@google.com> wrote:
> Hi H.J.,
>
> Could you show me why you postpone the setting
> ix86_tls_descriptor_calls_expanded_in_cfun until reload_complete and
> use ix86_tls_descriptor_calls_expanded_in_cfun instead of
> ix86_current_function_calls_tls_descriptor? Isn't
> ix86_current_function_calls_tls_descriptor useful to consider the case
> that tls call is optimized away?
>
When a tls call is optimized away, it won't survive reload.
If it does survive reload, it isn't optimized away. Also
checking df_regs_ever_live_p (SP_REG) isn't reliable
when called from ix86_compute_frame_layout.
--
H.J.