* [AArch64] Rework ARMv8.1 command line options.
@ 2015-11-16 16:31 Matthew Wahab
2015-11-16 17:15 ` Andrew Pinski
2015-11-24 15:23 ` James Greenhalgh
0 siblings, 2 replies; 6+ messages in thread
From: Matthew Wahab @ 2015-11-16 16:31 UTC (permalink / raw)
To: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 1579 bytes --]
Hello,
The command line options for target selection allow ARMv8.1 extensions
to be individually enabled/disabled. They also allow the extensions to
be enabled with -march=armv8-a. This doesn't reflect the ARMv8.1
architecture which requires all extensions to be enabled and doesn't make
them available for ARMv8.
This patch removes the options for the individual ARMv8.1 extensions
except for +lse. This means that setting -march=armv8.1-a will enable
all extensions required by ARMv8.1 and that the ARMv8.1 extensions can't
be used with -march=armv8.
The exception to this is +lse since there may be existing code expecting
to be built with -march=armv8-a+lse. Note that +crc, which is enabled by
-march=armv8.1-a, is still an option for -march=armv8-a.
This patch depends on the patch series
https://gcc.gnu.org/ml/gcc-patches/2015-10/msg02429.html.
Tested aarch64-none-elf with cross-compiled check-gcc and
aarch64-none-linux-gnu with native bootstrap and make check.
Ok for trunk?
Matthew
gcc/
2015-11-16 Matthew Wahab <matthew.wahab@arm.com>
* config/aarch64/aarch64-options-extensions.def: Remove
AARCH64_FL_RDMA from "fp" and "simd". Remove "pan", "lor",
"rdma".
* config/aarch64/aarch64.h (AARCH64_FL_PAN): Remove.
(AARCH64_FL_LOR): Remove.
(AARCH64_FL_RDMA): Remove.
(AARCH64_FL_V8_1): New.
(AARCH64_FL_FOR_AARCH8_1): Replace AARCH64_FL_PAN, AARCH64_FL_LOR
and AARCH64_FL_RDMA with AARCH64_FL_V8_1.
(AARCH64_ISA_RDMA): Replace AARCH64_FL_RDMA with AARCH64_FL_V8_1.
* doc/invoke.texi (AArch64 - Feature Modifiers): Remove "pan",
"lor" and "rdma".
[-- Attachment #2: rework_armv8_1_opts.patch --]
[-- Type: text/x-patch, Size: 4296 bytes --]
From bc4ea389754127ec639ea2de085a7c82aebae117 Mon Sep 17 00:00:00 2001
From: Matthew Wahab <matthew.wahab@arm.com>
Date: Fri, 30 Oct 2015 10:32:59 +0000
Subject: [PATCH] [AArch64] Rework ARMv8.1 command line options.
Change-Id: Ib9053719f45980255a3d7727e226a53d9f214049
---
gcc/config/aarch64/aarch64-option-extensions.def | 9 ++++-----
gcc/config/aarch64/aarch64.h | 9 +++------
gcc/doc/invoke.texi | 7 -------
3 files changed, 7 insertions(+), 18 deletions(-)
diff --git a/gcc/config/aarch64/aarch64-option-extensions.def b/gcc/config/aarch64/aarch64-option-extensions.def
index b261a0f..4f1d535 100644
--- a/gcc/config/aarch64/aarch64-option-extensions.def
+++ b/gcc/config/aarch64/aarch64-option-extensions.def
@@ -34,11 +34,10 @@
should contain a whitespace-separated list of the strings in 'Features'
that are required. Their order is not important. */
-AARCH64_OPT_EXTENSION("fp", AARCH64_FL_FP, AARCH64_FL_FPSIMD | AARCH64_FL_CRYPTO | AARCH64_FL_RDMA, "fp")
-AARCH64_OPT_EXTENSION("simd", AARCH64_FL_FPSIMD, AARCH64_FL_SIMD | AARCH64_FL_CRYPTO | AARCH64_FL_RDMA, "asimd")
+AARCH64_OPT_EXTENSION ("fp", AARCH64_FL_FP,
+ AARCH64_FL_FPSIMD | AARCH64_FL_CRYPTO, "fp")
+AARCH64_OPT_EXTENSION ("simd", AARCH64_FL_FPSIMD,
+ AARCH64_FL_SIMD | AARCH64_FL_CRYPTO, "asimd")
AARCH64_OPT_EXTENSION("crypto", AARCH64_FL_CRYPTO | AARCH64_FL_FPSIMD, AARCH64_FL_CRYPTO, "aes pmull sha1 sha2")
AARCH64_OPT_EXTENSION("crc", AARCH64_FL_CRC, AARCH64_FL_CRC, "crc32")
AARCH64_OPT_EXTENSION("lse", AARCH64_FL_LSE, AARCH64_FL_LSE, "lse")
-AARCH64_OPT_EXTENSION("pan", AARCH64_FL_PAN, AARCH64_FL_PAN, "pan")
-AARCH64_OPT_EXTENSION("lor", AARCH64_FL_LOR, AARCH64_FL_LOR, "lor")
-AARCH64_OPT_EXTENSION("rdma", AARCH64_FL_RDMA | AARCH64_FL_FPSIMD, AARCH64_FL_RDMA, "rdma")
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 68c006f..06345f0 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -134,9 +134,7 @@ extern unsigned aarch64_architecture_version;
#define AARCH64_FL_CRC (1 << 3) /* Has CRC. */
/* ARMv8.1 architecture extensions. */
#define AARCH64_FL_LSE (1 << 4) /* Has Large System Extensions. */
-#define AARCH64_FL_PAN (1 << 5) /* Has Privileged Access Never. */
-#define AARCH64_FL_LOR (1 << 6) /* Has Limited Ordering regions. */
-#define AARCH64_FL_RDMA (1 << 7) /* Has ARMv8.1 Adv.SIMD. */
+#define AARCH64_FL_V8_1 (1 << 5) /* Has ARMv8.1 extensions. */
/* Has FP and SIMD. */
#define AARCH64_FL_FPSIMD (AARCH64_FL_FP | AARCH64_FL_SIMD)
@@ -147,8 +145,7 @@ extern unsigned aarch64_architecture_version;
/* Architecture flags that effect instruction selection. */
#define AARCH64_FL_FOR_ARCH8 (AARCH64_FL_FPSIMD)
#define AARCH64_FL_FOR_ARCH8_1 \
- (AARCH64_FL_FOR_ARCH8 | AARCH64_FL_LSE | AARCH64_FL_PAN \
- | AARCH64_FL_LOR | AARCH64_FL_RDMA)
+ (AARCH64_FL_FOR_ARCH8 | AARCH64_FL_LSE | AARCH64_FL_V8_1)
/* Macros to test ISA flags. */
@@ -157,7 +154,7 @@ extern unsigned aarch64_architecture_version;
#define AARCH64_ISA_FP (aarch64_isa_flags & AARCH64_FL_FP)
#define AARCH64_ISA_SIMD (aarch64_isa_flags & AARCH64_FL_SIMD)
#define AARCH64_ISA_LSE (aarch64_isa_flags & AARCH64_FL_LSE)
-#define AARCH64_ISA_RDMA (aarch64_isa_flags & AARCH64_FL_RDMA)
+#define AARCH64_ISA_RDMA (aarch64_isa_flags & AARCH64_FL_V8_1)
/* Crypto is an optional extension to AdvSIMD. */
#define TARGET_CRYPTO (TARGET_SIMD && AARCH64_ISA_CRYPTO)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8057ac9..710198a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -12674,13 +12674,6 @@ 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
-Enable Privileged Access Never support.
-@item lor
-Enable Limited Ordering Regions support.
-@item rdma
-Enable ARMv8.1 Advanced SIMD instructions. This implies Advanced SIMD
-is enabled.
@end table
--
2.1.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [AArch64] Rework ARMv8.1 command line options.
2015-11-16 16:31 [AArch64] Rework ARMv8.1 command line options Matthew Wahab
@ 2015-11-16 17:15 ` Andrew Pinski
2015-11-24 15:23 ` James Greenhalgh
1 sibling, 0 replies; 6+ messages in thread
From: Andrew Pinski @ 2015-11-16 17:15 UTC (permalink / raw)
To: Matthew Wahab; +Cc: gcc-patches
On Mon, Nov 16, 2015 at 8:31 AM, Matthew Wahab
<matthew.wahab@foss.arm.com> wrote:
> Hello,
>
> The command line options for target selection allow ARMv8.1 extensions
> to be individually enabled/disabled. They also allow the extensions to
> be enabled with -march=armv8-a. This doesn't reflect the ARMv8.1
> architecture which requires all extensions to be enabled and doesn't make
> them available for ARMv8.
>
> This patch removes the options for the individual ARMv8.1 extensions
> except for +lse. This means that setting -march=armv8.1-a will enable
> all extensions required by ARMv8.1 and that the ARMv8.1 extensions can't
> be used with -march=armv8.
>
> The exception to this is +lse since there may be existing code expecting
> to be built with -march=armv8-a+lse. Note that +crc, which is enabled by
> -march=armv8.1-a, is still an option for -march=armv8-a.
>
> This patch depends on the patch series
> https://gcc.gnu.org/ml/gcc-patches/2015-10/msg02429.html.
>
> Tested aarch64-none-elf with cross-compiled check-gcc and
> aarch64-none-linux-gnu with native bootstrap and make check.
I like this patch. Note I was going to soon submit patches to change
thunderx over to 8.1-a and add thunderxt88pass1 which is 8-a.
But I need a few more patches to get to get that.
Thanks,
Andrew
>
> Ok for trunk?
> Matthew
>
> gcc/
> 2015-11-16 Matthew Wahab <matthew.wahab@arm.com>
>
> * config/aarch64/aarch64-options-extensions.def: Remove
> AARCH64_FL_RDMA from "fp" and "simd". Remove "pan", "lor",
> "rdma".
> * config/aarch64/aarch64.h (AARCH64_FL_PAN): Remove.
> (AARCH64_FL_LOR): Remove.
> (AARCH64_FL_RDMA): Remove.
> (AARCH64_FL_V8_1): New.
> (AARCH64_FL_FOR_AARCH8_1): Replace AARCH64_FL_PAN, AARCH64_FL_LOR
> and AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> (AARCH64_ISA_RDMA): Replace AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> * doc/invoke.texi (AArch64 - Feature Modifiers): Remove "pan",
> "lor" and "rdma".
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [AArch64] Rework ARMv8.1 command line options.
2015-11-16 16:31 [AArch64] Rework ARMv8.1 command line options Matthew Wahab
2015-11-16 17:15 ` Andrew Pinski
@ 2015-11-24 15:23 ` James Greenhalgh
2015-11-27 9:26 ` Matthew Wahab
1 sibling, 1 reply; 6+ messages in thread
From: James Greenhalgh @ 2015-11-24 15:23 UTC (permalink / raw)
To: Matthew Wahab; +Cc: gcc-patches
On Mon, Nov 16, 2015 at 04:31:32PM +0000, Matthew Wahab wrote:
> Hello,
>
> The command line options for target selection allow ARMv8.1 extensions
> to be individually enabled/disabled. They also allow the extensions to
> be enabled with -march=armv8-a. This doesn't reflect the ARMv8.1
> architecture which requires all extensions to be enabled and doesn't make
> them available for ARMv8.
>
> This patch removes the options for the individual ARMv8.1 extensions
> except for +lse. This means that setting -march=armv8.1-a will enable
> all extensions required by ARMv8.1 and that the ARMv8.1 extensions can't
> be used with -march=armv8.
>
> The exception to this is +lse since there may be existing code expecting
> to be built with -march=armv8-a+lse. Note that +crc, which is enabled by
> -march=armv8.1-a, is still an option for -march=armv8-a.
>
> This patch depends on the patch series
> https://gcc.gnu.org/ml/gcc-patches/2015-10/msg02429.html.
>
> Tested aarch64-none-elf with cross-compiled check-gcc and
> aarch64-none-linux-gnu with native bootstrap and make check.
>
> Ok for trunk?
> Matthew
>
> gcc/
> 2015-11-16 Matthew Wahab <matthew.wahab@arm.com>
>
> * config/aarch64/aarch64-options-extensions.def: Remove
> AARCH64_FL_RDMA from "fp" and "simd". Remove "pan", "lor",
> "rdma".
> * config/aarch64/aarch64.h (AARCH64_FL_PAN): Remove.
> (AARCH64_FL_LOR): Remove.
> (AARCH64_FL_RDMA): Remove.
> (AARCH64_FL_V8_1): New.
> (AARCH64_FL_FOR_AARCH8_1): Replace AARCH64_FL_PAN, AARCH64_FL_LOR
> and AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> (AARCH64_ISA_RDMA): Replace AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> * doc/invoke.texi (AArch64 - Feature Modifiers): Remove "pan",
> "lor" and "rdma".
I think I mentioned it in another review, but this patch seems a good place
to solve the problem. Could you please update the documentation to explain
what you've written above. As it stands I find myself confused by which
features GCC will make available at -march=armv8-a and -march=armv8.1-a.
Thanks,
James
> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
> index 8057ac9..710198a 100644
> --- a/gcc/doc/invoke.texi
> +++ b/gcc/doc/invoke.texi
> @@ -12674,13 +12674,6 @@ 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
> -Enable Privileged Access Never support.
> -@item lor
> -Enable Limited Ordering Regions support.
> -@item rdma
> -Enable ARMv8.1 Advanced SIMD instructions. This implies Advanced SIMD
> -is enabled.
>
> @end table
>
> --
> 2.1.4
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [AArch64] Rework ARMv8.1 command line options.
2015-11-24 15:23 ` James Greenhalgh
@ 2015-11-27 9:26 ` Matthew Wahab
2015-12-07 11:09 ` Matthew Wahab
0 siblings, 1 reply; 6+ messages in thread
From: Matthew Wahab @ 2015-11-27 9:26 UTC (permalink / raw)
To: James Greenhalgh; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 2527 bytes --]
On 24/11/15 15:22, James Greenhalgh wrote:
> On Mon, Nov 16, 2015 at 04:31:32PM +0000, Matthew Wahab wrote:
>>
>> The command line options for target selection allow ARMv8.1 extensions
>> to be individually enabled/disabled. They also allow the extensions to
>> be enabled with -march=armv8-a. This doesn't reflect the ARMv8.1
>> architecture which requires all extensions to be enabled and doesn't make
>> them available for ARMv8.
>>
>> This patch removes the options for the individual ARMv8.1 extensions
>> except for +lse. This means that setting -march=armv8.1-a will enable
>> all extensions required by ARMv8.1 and that the ARMv8.1 extensions can't
>> be used with -march=armv8.
> I think I mentioned it in another review, but this patch seems a good place
> to solve the problem. Could you please update the documentation to explain
> what you've written above. As it stands I find myself confused by which
> features GCC will make available at -march=armv8-a and -march=armv8.1-a.
Attached is a patch with the documentation for the AArch64 -march option
reworked to try to make it clearer what the -march=armv8.1-a option will
do. Extensions with feature modifiers (+crc, +lse) are explicitly stated
as being enabled by -march=armv8.1-a. Extensions without feature
modifiers (RDMA, PAN, LOR) are treated as part of the generic 'ARMv8.1
architecture extension' term in the description of -march=armv8.1-a.
I've also rearranged the -march section, to put the description of the
values for -march together and reworded the description of the
-march=native option.
Matthew
2015-11-26 Matthew Wahab <matthew.wahab@arm.com>
* config/aarch64/aarch64-options-extensions.def: Remove
AARCH64_FL_RDMA from "fp" and "simd". Remove "pan", "lor",
"rdma".
* config/aarch64/aarch64.h (AARCH64_FL_PAN): Remove.
(AARCH64_FL_LOR): Remove.
(AARCH64_FL_RDMA): Remove.
(AARCH64_FL_V8_1): New.
(AARCH64_FL_FOR_AARCH8_1): Replace AARCH64_FL_PAN, AARCH64_FL_LOR
and AARCH64_FL_RDMA with AARCH64_FL_V8_1.
(AARCH64_ISA_RDMA): Replace AARCH64_FL_RDMA with AARCH64_FL_V8_1.
* doc/invoke.texi (AArch64 -march): Rewrite initial paragraph and
section on -march=native. Group descriptions of permitted
architecture names together. Expand description of
-march=armv8.1-a.
(AArch64 -mtune): Slightly rework section on -march=native.
(AArch64 -mcpu): Slightly rework section on -march=native.
(AArch64 Feature Modifiers): Remove "pan", "lor" and "rdma".
State that -march=armv8.1-a enables "crc" and "lse".
[-- Attachment #2: 0001-AArch64-Rework-ARMv8.1-command-line-options.patch --]
[-- Type: text/x-patch, Size: 7695 bytes --]
diff --git a/gcc/config/aarch64/aarch64-option-extensions.def b/gcc/config/aarch64/aarch64-option-extensions.def
index b261a0f7c3c6f5264fe4f95c85a59535aa951ce4..4f1d53515a9a4ff8920fadb13164c85e39990db5 100644
--- a/gcc/config/aarch64/aarch64-option-extensions.def
+++ b/gcc/config/aarch64/aarch64-option-extensions.def
@@ -34,11 +34,10 @@
should contain a whitespace-separated list of the strings in 'Features'
that are required. Their order is not important. */
-AARCH64_OPT_EXTENSION("fp", AARCH64_FL_FP, AARCH64_FL_FPSIMD | AARCH64_FL_CRYPTO | AARCH64_FL_RDMA, "fp")
-AARCH64_OPT_EXTENSION("simd", AARCH64_FL_FPSIMD, AARCH64_FL_SIMD | AARCH64_FL_CRYPTO | AARCH64_FL_RDMA, "asimd")
+AARCH64_OPT_EXTENSION ("fp", AARCH64_FL_FP,
+ AARCH64_FL_FPSIMD | AARCH64_FL_CRYPTO, "fp")
+AARCH64_OPT_EXTENSION ("simd", AARCH64_FL_FPSIMD,
+ AARCH64_FL_SIMD | AARCH64_FL_CRYPTO, "asimd")
AARCH64_OPT_EXTENSION("crypto", AARCH64_FL_CRYPTO | AARCH64_FL_FPSIMD, AARCH64_FL_CRYPTO, "aes pmull sha1 sha2")
AARCH64_OPT_EXTENSION("crc", AARCH64_FL_CRC, AARCH64_FL_CRC, "crc32")
AARCH64_OPT_EXTENSION("lse", AARCH64_FL_LSE, AARCH64_FL_LSE, "lse")
-AARCH64_OPT_EXTENSION("pan", AARCH64_FL_PAN, AARCH64_FL_PAN, "pan")
-AARCH64_OPT_EXTENSION("lor", AARCH64_FL_LOR, AARCH64_FL_LOR, "lor")
-AARCH64_OPT_EXTENSION("rdma", AARCH64_FL_RDMA | AARCH64_FL_FPSIMD, AARCH64_FL_RDMA, "rdma")
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 68c006fa91f6326140cf447c7f4578ac46c24f79..06345f0215ea190b7b089264a0039a201437ecec 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -134,9 +134,7 @@ extern unsigned aarch64_architecture_version;
#define AARCH64_FL_CRC (1 << 3) /* Has CRC. */
/* ARMv8.1 architecture extensions. */
#define AARCH64_FL_LSE (1 << 4) /* Has Large System Extensions. */
-#define AARCH64_FL_PAN (1 << 5) /* Has Privileged Access Never. */
-#define AARCH64_FL_LOR (1 << 6) /* Has Limited Ordering regions. */
-#define AARCH64_FL_RDMA (1 << 7) /* Has ARMv8.1 Adv.SIMD. */
+#define AARCH64_FL_V8_1 (1 << 5) /* Has ARMv8.1 extensions. */
/* Has FP and SIMD. */
#define AARCH64_FL_FPSIMD (AARCH64_FL_FP | AARCH64_FL_SIMD)
@@ -147,8 +145,7 @@ extern unsigned aarch64_architecture_version;
/* Architecture flags that effect instruction selection. */
#define AARCH64_FL_FOR_ARCH8 (AARCH64_FL_FPSIMD)
#define AARCH64_FL_FOR_ARCH8_1 \
- (AARCH64_FL_FOR_ARCH8 | AARCH64_FL_LSE | AARCH64_FL_PAN \
- | AARCH64_FL_LOR | AARCH64_FL_RDMA)
+ (AARCH64_FL_FOR_ARCH8 | AARCH64_FL_LSE | AARCH64_FL_V8_1)
/* Macros to test ISA flags. */
@@ -157,7 +154,7 @@ extern unsigned aarch64_architecture_version;
#define AARCH64_ISA_FP (aarch64_isa_flags & AARCH64_FL_FP)
#define AARCH64_ISA_SIMD (aarch64_isa_flags & AARCH64_FL_SIMD)
#define AARCH64_ISA_LSE (aarch64_isa_flags & AARCH64_FL_LSE)
-#define AARCH64_ISA_RDMA (aarch64_isa_flags & AARCH64_FL_RDMA)
+#define AARCH64_ISA_RDMA (aarch64_isa_flags & AARCH64_FL_V8_1)
/* Crypto is an optional extension to AdvSIMD. */
#define TARGET_CRYPTO (TARGET_SIMD && AARCH64_ISA_CRYPTO)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index f8e8e5d477b08015445aa245acc00ae079e1eb9b..4332f42c4445e0d4c7455551aa4fa91e5cd2b73d 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -12566,23 +12566,27 @@ Which in turn depends on the target processor.
@item -march=@var{name}
@opindex march
-Specify the name of the target architecture, optionally suffixed by one or
+Specify the name of the target architecture and, optionally, one or
more feature modifiers. This option has the form
@option{-march=@var{arch}@r{@{}+@r{[}no@r{]}@var{feature}@r{@}*}}.
-The permissible values for @var{arch} are @samp{armv8-a} or
-@samp{armv8.1-a}.
+The permissible values for @var{arch} are @samp{armv8-a},
+@samp{armv8.1-a} or @var{native}.
-For the permissible values for @var{feature}, see the sub-section on
-@ref{aarch64-feature-modifiers,,@option{-march} and @option{-mcpu}
+The value @samp{armv8.1-a} implies @samp{armv8-a} and enables compiler
+support for the ARMv8.1 architecture extension. In particular, it
+enables the @samp{+crc} and @samp{+lse} features.
+
+The value @samp{native} is available on native AArch64 GNU/Linux and
+causes the compiler to pick the architecture of the host system. This
+option has no effect if the compiler is unable to recognize the
+architecture of the host system,
+
+The permissible values for @var{feature} are listed in the sub-section
+on @ref{aarch64-feature-modifiers,,@option{-march} and @option{-mcpu}
Feature Modifiers}. Where conflicting feature modifiers are
specified, the right-most feature is used.
-Additionally on native AArch64 GNU/Linux systems the value
-@samp{native} is available. This option causes the compiler to pick the
-architecture of the host system. If the compiler is unable to recognize the
-architecture of the host system this option has no effect.
-
GCC uses @var{name} to determine what kind of instructions it can emit
when generating assembly code. If @option{-march} is specified
without either of @option{-mtune} or @option{-mcpu} also being
@@ -12604,8 +12608,8 @@ option are: @samp{cortex-a57.cortex-a53}, @samp{cortex-a72.cortex-a53}.
Additionally on native AArch64 GNU/Linux systems the value
@samp{native} is available. This option causes the compiler to pick
the architecture of and tune the performance of the code for the
-processor of the host system. If the compiler is unable to recognize
-the processor of the host system this option has no effect.
+processor of the host system. This option has no effect if the
+compiler is unable to recognize the architecture of the host system.
Where none of @option{-mtune=}, @option{-mcpu=} or @option{-march=}
are specified, the code is tuned to perform well across a range
@@ -12627,9 +12631,9 @@ specified, the right-most feature is used.
Additionally on native AArch64 GNU/Linux systems the value
@samp{native} is available. This option causes the compiler to tune
-the performance of the code for the processor of the host system. If
-the compiler is unable to recognize the processor of the host system
-this option has no effect.
+the performance of the code for the processor of the host system.
+This option has no effect if the compiler is unable to recognize the
+architecture of the host system.
GCC uses @var{name} to determine what kind of instructions it can emit when
generating assembly code (as if by @option{-march}) and to determine
@@ -12665,7 +12669,8 @@ the following and their inverses @option{no@var{feature}}:
@table @samp
@item crc
-Enable CRC extension.
+Enable CRC extension. This is on by default for
+@option{-march=armv8.1-a}.
@item crypto
Enable Crypto extension. This also enables Advanced SIMD and floating-point
instructions.
@@ -12677,14 +12682,8 @@ 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
-Enable Privileged Access Never support.
-@item lor
-Enable Limited Ordering Regions support.
-@item rdma
-Enable ARMv8.1 Advanced SIMD instructions. This implies Advanced SIMD
-is enabled.
+Enable Large System Extension instructions. This is on by default for
+@option{-march=armv8.1-a}.
@end table
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [AArch64] Rework ARMv8.1 command line options.
2015-11-27 9:26 ` Matthew Wahab
@ 2015-12-07 11:09 ` Matthew Wahab
2015-12-07 14:41 ` James Greenhalgh
0 siblings, 1 reply; 6+ messages in thread
From: Matthew Wahab @ 2015-12-07 11:09 UTC (permalink / raw)
To: James Greenhalgh; +Cc: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 2779 bytes --]
Ping. Updated patch attached.
Matthew
On 27/11/15 09:23, Matthew Wahab wrote:
> On 24/11/15 15:22, James Greenhalgh wrote:
> > On Mon, Nov 16, 2015 at 04:31:32PM +0000, Matthew Wahab wrote:
> >>
> >> The command line options for target selection allow ARMv8.1 extensions
> >> to be individually enabled/disabled. They also allow the extensions to
> >> be enabled with -march=armv8-a. This doesn't reflect the ARMv8.1
> >> architecture which requires all extensions to be enabled and doesn't make
> >> them available for ARMv8.
> >>
> >> This patch removes the options for the individual ARMv8.1 extensions
> >> except for +lse. This means that setting -march=armv8.1-a will enable
> >> all extensions required by ARMv8.1 and that the ARMv8.1 extensions can't
> >> be used with -march=armv8.
>
> > I think I mentioned it in another review, but this patch seems a good place
> > to solve the problem. Could you please update the documentation to explain
> > what you've written above. As it stands I find myself confused by which
> > features GCC will make available at -march=armv8-a and -march=armv8.1-a.
>
> Attached is a patch with the documentation for the AArch64 -march option
> reworked to try to make it clearer what the -march=armv8.1-a option will
> do. Extensions with feature modifiers (+crc, +lse) are explicitly stated
> as being enabled by -march=armv8.1-a. Extensions without feature
> modifiers (RDMA, PAN, LOR) are treated as part of the generic 'ARMv8.1
> architecture extension' term in the description of -march=armv8.1-a.
>
> I've also rearranged the -march section, to put the description of the
> values for -march together and reworded the description of the
> -march=native option.
>
> Matthew
>
> 2015-11-26 Matthew Wahab <matthew.wahab@arm.com>
>
> * config/aarch64/aarch64-options-extensions.def: Remove
> AARCH64_FL_RDMA from "fp" and "simd". Remove "pan", "lor",
> "rdma".
> * config/aarch64/aarch64.h (AARCH64_FL_PAN): Remove.
> (AARCH64_FL_LOR): Remove.
> (AARCH64_FL_RDMA): Remove.
> (AARCH64_FL_V8_1): New.
> (AARCH64_FL_FOR_AARCH8_1): Replace AARCH64_FL_PAN, AARCH64_FL_LOR
> and AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> (AARCH64_ISA_RDMA): Replace AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> * doc/invoke.texi (AArch64 -march): Rewrite initial paragraph and
> section on -march=native. Group descriptions of permitted
> architecture names together. Expand description of
> -march=armv8.1-a.
> (AArch64 -mtune): Slightly rework section on -march=native.
> (AArch64 -mcpu): Slightly rework section on -march=native.
> (AArch64 Feature Modifiers): Remove "pan", "lor" and "rdma".
> State that -march=armv8.1-a enables "crc" and "lse".
>
[-- Attachment #2: 0001-AArch64-Rework-ARMv8.1-command-line-options.patch --]
[-- Type: text/x-patch, Size: 8038 bytes --]
From 498323fc1992cd75070e86f195d4bba09a5e02e0 Mon Sep 17 00:00:00 2001
From: Matthew Wahab <matthew.wahab@arm.com>
Date: Fri, 30 Oct 2015 10:32:59 +0000
Subject: [PATCH] [AArch64] Rework ARMv8.1 command line options.
Change-Id: Ib9053719f45980255a3d7727e226a53d9f214049
---
gcc/config/aarch64/aarch64-option-extensions.def | 9 ++---
gcc/config/aarch64/aarch64.h | 9 ++---
gcc/doc/invoke.texi | 47 ++++++++++++------------
3 files changed, 30 insertions(+), 35 deletions(-)
diff --git a/gcc/config/aarch64/aarch64-option-extensions.def b/gcc/config/aarch64/aarch64-option-extensions.def
index b261a0f..4f1d535 100644
--- a/gcc/config/aarch64/aarch64-option-extensions.def
+++ b/gcc/config/aarch64/aarch64-option-extensions.def
@@ -34,11 +34,10 @@
should contain a whitespace-separated list of the strings in 'Features'
that are required. Their order is not important. */
-AARCH64_OPT_EXTENSION("fp", AARCH64_FL_FP, AARCH64_FL_FPSIMD | AARCH64_FL_CRYPTO | AARCH64_FL_RDMA, "fp")
-AARCH64_OPT_EXTENSION("simd", AARCH64_FL_FPSIMD, AARCH64_FL_SIMD | AARCH64_FL_CRYPTO | AARCH64_FL_RDMA, "asimd")
+AARCH64_OPT_EXTENSION ("fp", AARCH64_FL_FP,
+ AARCH64_FL_FPSIMD | AARCH64_FL_CRYPTO, "fp")
+AARCH64_OPT_EXTENSION ("simd", AARCH64_FL_FPSIMD,
+ AARCH64_FL_SIMD | AARCH64_FL_CRYPTO, "asimd")
AARCH64_OPT_EXTENSION("crypto", AARCH64_FL_CRYPTO | AARCH64_FL_FPSIMD, AARCH64_FL_CRYPTO, "aes pmull sha1 sha2")
AARCH64_OPT_EXTENSION("crc", AARCH64_FL_CRC, AARCH64_FL_CRC, "crc32")
AARCH64_OPT_EXTENSION("lse", AARCH64_FL_LSE, AARCH64_FL_LSE, "lse")
-AARCH64_OPT_EXTENSION("pan", AARCH64_FL_PAN, AARCH64_FL_PAN, "pan")
-AARCH64_OPT_EXTENSION("lor", AARCH64_FL_LOR, AARCH64_FL_LOR, "lor")
-AARCH64_OPT_EXTENSION("rdma", AARCH64_FL_RDMA | AARCH64_FL_FPSIMD, AARCH64_FL_RDMA, "rdma")
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index 68c006f..06345f0 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -134,9 +134,7 @@ extern unsigned aarch64_architecture_version;
#define AARCH64_FL_CRC (1 << 3) /* Has CRC. */
/* ARMv8.1 architecture extensions. */
#define AARCH64_FL_LSE (1 << 4) /* Has Large System Extensions. */
-#define AARCH64_FL_PAN (1 << 5) /* Has Privileged Access Never. */
-#define AARCH64_FL_LOR (1 << 6) /* Has Limited Ordering regions. */
-#define AARCH64_FL_RDMA (1 << 7) /* Has ARMv8.1 Adv.SIMD. */
+#define AARCH64_FL_V8_1 (1 << 5) /* Has ARMv8.1 extensions. */
/* Has FP and SIMD. */
#define AARCH64_FL_FPSIMD (AARCH64_FL_FP | AARCH64_FL_SIMD)
@@ -147,8 +145,7 @@ extern unsigned aarch64_architecture_version;
/* Architecture flags that effect instruction selection. */
#define AARCH64_FL_FOR_ARCH8 (AARCH64_FL_FPSIMD)
#define AARCH64_FL_FOR_ARCH8_1 \
- (AARCH64_FL_FOR_ARCH8 | AARCH64_FL_LSE | AARCH64_FL_PAN \
- | AARCH64_FL_LOR | AARCH64_FL_RDMA)
+ (AARCH64_FL_FOR_ARCH8 | AARCH64_FL_LSE | AARCH64_FL_V8_1)
/* Macros to test ISA flags. */
@@ -157,7 +154,7 @@ extern unsigned aarch64_architecture_version;
#define AARCH64_ISA_FP (aarch64_isa_flags & AARCH64_FL_FP)
#define AARCH64_ISA_SIMD (aarch64_isa_flags & AARCH64_FL_SIMD)
#define AARCH64_ISA_LSE (aarch64_isa_flags & AARCH64_FL_LSE)
-#define AARCH64_ISA_RDMA (aarch64_isa_flags & AARCH64_FL_RDMA)
+#define AARCH64_ISA_RDMA (aarch64_isa_flags & AARCH64_FL_V8_1)
/* Crypto is an optional extension to AdvSIMD. */
#define TARGET_CRYPTO (TARGET_SIMD && AARCH64_ISA_CRYPTO)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 33f579f..679ce9d 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -12569,23 +12569,27 @@ Which in turn depends on the target processor.
@item -march=@var{name}
@opindex march
-Specify the name of the target architecture, optionally suffixed by one or
+Specify the name of the target architecture and, optionally, one or
more feature modifiers. This option has the form
@option{-march=@var{arch}@r{@{}+@r{[}no@r{]}@var{feature}@r{@}*}}.
-The permissible values for @var{arch} are @samp{armv8-a} or
-@samp{armv8.1-a}.
+The permissible values for @var{arch} are @samp{armv8-a},
+@samp{armv8.1-a} or @var{native}.
-For the permissible values for @var{feature}, see the sub-section on
-@ref{aarch64-feature-modifiers,,@option{-march} and @option{-mcpu}
+The value @samp{armv8.1-a} implies @samp{armv8-a} and enables compiler
+support for the ARMv8.1 architecture extension. In particular, it
+enables the @samp{+crc} and @samp{+lse} features.
+
+The value @samp{native} is available on native AArch64 GNU/Linux and
+causes the compiler to pick the architecture of the host system. This
+option has no effect if the compiler is unable to recognize the
+architecture of the host system,
+
+The permissible values for @var{feature} are listed in the sub-section
+on @ref{aarch64-feature-modifiers,,@option{-march} and @option{-mcpu}
Feature Modifiers}. Where conflicting feature modifiers are
specified, the right-most feature is used.
-Additionally on native AArch64 GNU/Linux systems the value
-@samp{native} is available. This option causes the compiler to pick the
-architecture of the host system. If the compiler is unable to recognize the
-architecture of the host system this option has no effect.
-
GCC uses @var{name} to determine what kind of instructions it can emit
when generating assembly code. If @option{-march} is specified
without either of @option{-mtune} or @option{-mcpu} also being
@@ -12607,8 +12611,8 @@ option are: @samp{cortex-a57.cortex-a53}, @samp{cortex-a72.cortex-a53}.
Additionally on native AArch64 GNU/Linux systems the value
@samp{native} is available. This option causes the compiler to pick
the architecture of and tune the performance of the code for the
-processor of the host system. If the compiler is unable to recognize
-the processor of the host system this option has no effect.
+processor of the host system. This option has no effect if the
+compiler is unable to recognize the architecture of the host system.
Where none of @option{-mtune=}, @option{-mcpu=} or @option{-march=}
are specified, the code is tuned to perform well across a range
@@ -12630,9 +12634,9 @@ specified, the right-most feature is used.
Additionally on native AArch64 GNU/Linux systems the value
@samp{native} is available. This option causes the compiler to tune
-the performance of the code for the processor of the host system. If
-the compiler is unable to recognize the processor of the host system
-this option has no effect.
+the performance of the code for the processor of the host system.
+This option has no effect if the compiler is unable to recognize the
+architecture of the host system.
GCC uses @var{name} to determine what kind of instructions it can emit when
generating assembly code (as if by @option{-march}) and to determine
@@ -12668,7 +12672,8 @@ the following and their inverses @option{no@var{feature}}:
@table @samp
@item crc
-Enable CRC extension.
+Enable CRC extension. This is on by default for
+@option{-march=armv8.1-a}.
@item crypto
Enable Crypto extension. This also enables Advanced SIMD and floating-point
instructions.
@@ -12680,14 +12685,8 @@ 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
-Enable Privileged Access Never support.
-@item lor
-Enable Limited Ordering Regions support.
-@item rdma
-Enable ARMv8.1 Advanced SIMD instructions. This implies Advanced SIMD
-is enabled.
+Enable Large System Extension instructions. This is on by default for
+@option{-march=armv8.1-a}.
@end table
--
2.1.4
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [AArch64] Rework ARMv8.1 command line options.
2015-12-07 11:09 ` Matthew Wahab
@ 2015-12-07 14:41 ` James Greenhalgh
0 siblings, 0 replies; 6+ messages in thread
From: James Greenhalgh @ 2015-12-07 14:41 UTC (permalink / raw)
To: Matthew Wahab; +Cc: gcc-patches
On Mon, Dec 07, 2015 at 11:09:52AM +0000, Matthew Wahab wrote:
> Ping. Updated patch attached.
This is OK, thanks.
James
>
> Matthew
>
> On 27/11/15 09:23, Matthew Wahab wrote:
> >On 24/11/15 15:22, James Greenhalgh wrote:
> > > On Mon, Nov 16, 2015 at 04:31:32PM +0000, Matthew Wahab wrote:
> > >>
> > >> The command line options for target selection allow ARMv8.1 extensions
> > >> to be individually enabled/disabled. They also allow the extensions to
> > >> be enabled with -march=armv8-a. This doesn't reflect the ARMv8.1
> > >> architecture which requires all extensions to be enabled and doesn't make
> > >> them available for ARMv8.
> > >>
> > >> This patch removes the options for the individual ARMv8.1 extensions
> > >> except for +lse. This means that setting -march=armv8.1-a will enable
> > >> all extensions required by ARMv8.1 and that the ARMv8.1 extensions can't
> > >> be used with -march=armv8.
> >
> > > I think I mentioned it in another review, but this patch seems a good place
> > > to solve the problem. Could you please update the documentation to explain
> > > what you've written above. As it stands I find myself confused by which
> > > features GCC will make available at -march=armv8-a and -march=armv8.1-a.
> >
> >Attached is a patch with the documentation for the AArch64 -march option
> >reworked to try to make it clearer what the -march=armv8.1-a option will
> >do. Extensions with feature modifiers (+crc, +lse) are explicitly stated
> >as being enabled by -march=armv8.1-a. Extensions without feature
> >modifiers (RDMA, PAN, LOR) are treated as part of the generic 'ARMv8.1
> >architecture extension' term in the description of -march=armv8.1-a.
> >
> >I've also rearranged the -march section, to put the description of the
> >values for -march together and reworded the description of the
> >-march=native option.
> >
> >Matthew
> >
> >2015-11-26 Matthew Wahab <matthew.wahab@arm.com>
> >
> > * config/aarch64/aarch64-options-extensions.def: Remove
> > AARCH64_FL_RDMA from "fp" and "simd". Remove "pan", "lor",
> > "rdma".
> > * config/aarch64/aarch64.h (AARCH64_FL_PAN): Remove.
> > (AARCH64_FL_LOR): Remove.
> > (AARCH64_FL_RDMA): Remove.
> > (AARCH64_FL_V8_1): New.
> > (AARCH64_FL_FOR_AARCH8_1): Replace AARCH64_FL_PAN, AARCH64_FL_LOR
> > and AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> > (AARCH64_ISA_RDMA): Replace AARCH64_FL_RDMA with AARCH64_FL_V8_1.
> > * doc/invoke.texi (AArch64 -march): Rewrite initial paragraph and
> > section on -march=native. Group descriptions of permitted
> > architecture names together. Expand description of
> > -march=armv8.1-a.
> > (AArch64 -mtune): Slightly rework section on -march=native.
> > (AArch64 -mcpu): Slightly rework section on -march=native.
> > (AArch64 Feature Modifiers): Remove "pan", "lor" and "rdma".
> > State that -march=armv8.1-a enables "crc" and "lse".
> >
>
^ permalink raw reply [flat|nested] 6+ messages in thread
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