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Re: [PATCH 2/3][AArch64 nofp] Clarify docs for +nofp/-mgeneral-regs-only
- From: James Greenhalgh <james dot greenhalgh at arm dot com>
- To: Alan Lawrence <Alan dot Lawrence at arm dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 24 Jun 2015 10:59:28 +0100
- Subject: Re: [PATCH 2/3][AArch64 nofp] Clarify docs for +nofp/-mgeneral-regs-only
- Authentication-results: sourceware.org; auth=none
- References: <557970C8 dot 8060604 at arm dot com> <20150616103140 dot GA14076 at arm dot com> <55898341 dot 4060701 at arm dot com>
On Tue, Jun 23, 2015 at 05:03:13PM +0100, Alan Lawrence wrote:
> James Greenhalgh wrote:
<<snip>>
> To my eye, beginning a sentence in lowercase looks very odd in pdf, and still a
> bit odd in html. Have changed to "That is"...?
>
> Tested with make pdf & make html.
>
> gcc/ChangeLog (unchanged):
>
> * doc/invoke.texi: Clarify AArch64 feature modifiers (no)fp, (no)simd
> and (no)crypto.
OK.
Thanks,
James
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index d8e982c3aa338819df3785696c493a66c1f5b674..0579bf2ecf993bb56987e0bb9686925537ab61e3 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -12359,7 +12359,10 @@ Generate big-endian code. This is the default when GCC is configured for an
>
> @item -mgeneral-regs-only
> @opindex mgeneral-regs-only
> -Generate code which uses only the general registers.
> +Generate code which uses only the general-purpose registers. This is equivalent
> +to feature modifier @option{nofp} of @option{-march} or @option{-mcpu}, except
> +that @option{-mgeneral-regs-only} takes precedence over any conflicting feature
> +modifier regardless of sequence.
>
> @item -mlittle-endian
> @opindex mlittle-endian
> @@ -12498,20 +12501,22 @@ over the appropriate part of this option.
> @subsubsection @option{-march} and @option{-mcpu} Feature Modifiers
> @cindex @option{-march} feature modifiers
> @cindex @option{-mcpu} feature modifiers
> -Feature modifiers used with @option{-march} and @option{-mcpu} can be one
> -the following:
> +Feature modifiers used with @option{-march} and @option{-mcpu} can be any of
> +the following and their inverses @option{no@var{feature}}:
>
> @table @samp
> @item crc
> Enable CRC extension.
> @item crypto
> -Enable Crypto extension. This implies Advanced SIMD is enabled.
> +Enable Crypto extension. This also enables Advanced SIMD and floating-point
> +instructions.
> @item fp
> -Enable floating-point instructions.
> +Enable floating-point instructions. This is on by default for all possible
> +values for options @option{-march} and @option{-mcpu}.
> @item simd
> -Enable Advanced SIMD instructions. This implies floating-point instructions
> -are enabled. This is the default for all current possible values for options
> -@option{-march} and @option{-mcpu=}.
> +Enable Advanced SIMD instructions. This also enables floating-point
> +instructions. This is on by default for all possible values for options
> +@option{-march} and @option{-mcpu}.
> @item lse
> Enable Large System Extension instructions.
> @item pan
> @@ -12522,6 +12527,10 @@ Enable Limited Ordering Regions support.
> Enable ARMv8.1 Advanced SIMD instructions.
> @end table
>
> +That is, @option{crypto} implies @option{simd} implies @option{fp}.
> +Conversely, @option{nofp} (or equivalently, @option{-mgeneral-regs-only})
> +implies @option{nosimd} implies @option{nocrypto}.
> +
> @node Adapteva Epiphany Options
> @subsection Adapteva Epiphany Options
>