Re: [PATCH 1/5] separate shrink-wrap: New command-line flag, status flag, hooks, and doc

[Jeff Law <law@redhat.com>]

On 09/23/2016 02:21 AM, Segher Boessenkool wrote:
> This patch adds a new command-line flag "-fshrink-wrap-separate", a status
> flag "shrink_wrapped_separate", hooks for abstracting the target components,
> and documentation for all those.
>
>
> 2016-09-23  Segher Boessenkool  <segher@kernel.crashing.org>
>
> 	* common.opt (-fshrink-wrap-separate): New flag.
> 	* doc/invoke.texi: Document it.
> 	* doc/tm.texi.in (Shrink-wrapping separate components): New subsection.
> 	* doc/tm.texi: Regenerate.
> 	* emit-rtl.h (struct rtl_data): New field shrink_wrapped_separate.
> 	* target.def (shrink_wrap): New hook vector.
> 	(get_separate_components, components_for_bb, disqualify_components,
> 	emit_prologue_components, emit_epilogue_components,
> 	set_handled_components): New hooks.
>
> ---
>  gcc/common.opt      |  4 ++++
>  gcc/doc/invoke.texi | 11 +++++++++-
>  gcc/doc/tm.texi     | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  gcc/doc/tm.texi.in  | 38 ++++++++++++++++++++++++++++++++
>  gcc/emit-rtl.h      |  4 ++++
>  gcc/target.def      | 57 ++++++++++++++++++++++++++++++++++++++++++++++++
>  6 files changed, 176 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/common.opt b/gcc/common.opt
> index fa1c036..1a38d12 100644
> --- a/gcc/common.opt
> +++ b/gcc/common.opt
> @@ -2189,6 +2189,10 @@ Common Report Var(flag_shrink_wrap) Optimization
>  Emit function prologues only before parts of the function that need it,
>  rather than at the top of the function.
>
> +fshrink-wrap-separate
> +Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
> +Shrink-wrap parts of the prologue and epilogue separately.
> +
>  fsignaling-nans
>  Common Report Var(flag_signaling_nans) Optimization SetByCombined
>  Disable optimizations observable by IEEE signaling NaNs.
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 8eb5eff..464b737 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -397,7 +397,8 @@ Objective-C and Objective-C++ Dialects}.
>  -fschedule-insns -fschedule-insns2 -fsection-anchors @gol
>  -fselective-scheduling -fselective-scheduling2 @gol
>  -fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
> --fsemantic-interposition -fshrink-wrap -fsignaling-nans @gol
> +-fsemantic-interposition -fshrink-wrap -fshrink-wrap-separate @gol
> +-fsignaling-nans @gol
>  -fsingle-precision-constant -fsplit-ivs-in-unroller @gol
>  -fsplit-paths @gol
>  -fsplit-wide-types -fssa-backprop -fssa-phiopt @gol
> @@ -6396,6 +6397,7 @@ compilation time.
>  -fmove-loop-invariants @gol
>  -freorder-blocks @gol
>  -fshrink-wrap @gol
> +-fshrink-wrap-separate @gol
>  -fsplit-wide-types @gol
>  -fssa-backprop @gol
>  -fssa-phiopt @gol
> @@ -7306,6 +7308,13 @@ Emit function prologues only before parts of the function that need it,
>  rather than at the top of the function.  This flag is enabled by default at
>  @option{-O} and higher.
>
> +@item -fshrink-wrap-separate
> +@opindex fshrink-wrap-separate
> +Shrink-wrap separate parts of the prologue and epilogue separately, so that
> +those parts are only executed when needed.
> +This option is on by default, but has no effect unless @option{-fshrink-wrap}
> +is also turned on.
This option also has no effect if the target has not implemented support 
for separate shrink wrapping.   Or something like that seems appropriate 
here.

I think with that change this patch is fine and can be committed with 
the main part once approved.

jeff