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(-)
@@ -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")
@@ -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)
@@ -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