From: Adrian Ratiu <adrian.ratiu@collabora.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Nathan Chancellor <natechancellor@gmail.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
Ard Biesheuvel <ardb@kernel.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
kernel@collabora.com,
clang-built-linux <clang-built-linux@googlegroups.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH v2 2/2] arm: lib: xor-neon: move pragma options to makefile
Date: Thu, 12 Nov 2020 23:24:57 +0200 [thread overview]
Message-ID: <20201112212457.2042105-3-adrian.ratiu@collabora.com> (raw)
In-Reply-To: <20201112212457.2042105-1-adrian.ratiu@collabora.com>
Using a pragma like GCC optimize is a bad idea because it tags
all functions with an __attribute__((optimize)) which replaces
optimization options rather than appending so could result in
dropping important flags. Not recommended for production use.
Because these options should always be enabled for this file,
it's better to set them via command line. tree-vectorize is on
by default in Clang, but it doesn't hurt to make it explicit.
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
---
arch/arm/lib/Makefile | 2 +-
arch/arm/lib/xor-neon.c | 10 ----------
2 files changed, 1 insertion(+), 11 deletions(-)
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 6d2ba454f25b..12d31d1a7630 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -45,6 +45,6 @@ $(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S
ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
NEON_FLAGS := -march=armv7-a -mfloat-abi=softfp -mfpu=neon
- CFLAGS_xor-neon.o += $(NEON_FLAGS)
+ CFLAGS_xor-neon.o += $(NEON_FLAGS) -ftree-vectorize -Wno-unused-variable
obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o
endif
diff --git a/arch/arm/lib/xor-neon.c b/arch/arm/lib/xor-neon.c
index e1e76186ec23..62b493e386c4 100644
--- a/arch/arm/lib/xor-neon.c
+++ b/arch/arm/lib/xor-neon.c
@@ -14,16 +14,6 @@ MODULE_LICENSE("GPL");
#error You should compile this file with '-march=armv7-a -mfloat-abi=softfp -mfpu=neon'
#endif
-/*
- * Pull in the reference implementations while instructing GCC (through
- * -ftree-vectorize) to attempt to exploit implicit parallelism and emit
- * NEON instructions.
- */
-#ifdef CONFIG_CC_IS_GCC
-#pragma GCC optimize "tree-vectorize"
-#endif
-
-#pragma GCC diagnostic ignored "-Wunused-variable"
#include <asm-generic/xor.h>
struct xor_block_template const xor_block_neon_inner = {
--
2.29.2
WARNING: multiple messages have this Message-ID (diff)
From: Adrian Ratiu <adrian.ratiu@collabora.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Arnd Bergmann <arnd@arndb.de>,
Nick Desaulniers <ndesaulniers@google.com>,
Russell King <linux@armlinux.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
Nathan Chancellor <natechancellor@gmail.com>,
kernel@collabora.com, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH v2 2/2] arm: lib: xor-neon: move pragma options to makefile
Date: Thu, 12 Nov 2020 23:24:57 +0200 [thread overview]
Message-ID: <20201112212457.2042105-3-adrian.ratiu@collabora.com> (raw)
In-Reply-To: <20201112212457.2042105-1-adrian.ratiu@collabora.com>
Using a pragma like GCC optimize is a bad idea because it tags
all functions with an __attribute__((optimize)) which replaces
optimization options rather than appending so could result in
dropping important flags. Not recommended for production use.
Because these options should always be enabled for this file,
it's better to set them via command line. tree-vectorize is on
by default in Clang, but it doesn't hurt to make it explicit.
Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
---
arch/arm/lib/Makefile | 2 +-
arch/arm/lib/xor-neon.c | 10 ----------
2 files changed, 1 insertion(+), 11 deletions(-)
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 6d2ba454f25b..12d31d1a7630 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -45,6 +45,6 @@ $(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S
ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
NEON_FLAGS := -march=armv7-a -mfloat-abi=softfp -mfpu=neon
- CFLAGS_xor-neon.o += $(NEON_FLAGS)
+ CFLAGS_xor-neon.o += $(NEON_FLAGS) -ftree-vectorize -Wno-unused-variable
obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o
endif
diff --git a/arch/arm/lib/xor-neon.c b/arch/arm/lib/xor-neon.c
index e1e76186ec23..62b493e386c4 100644
--- a/arch/arm/lib/xor-neon.c
+++ b/arch/arm/lib/xor-neon.c
@@ -14,16 +14,6 @@ MODULE_LICENSE("GPL");
#error You should compile this file with '-march=armv7-a -mfloat-abi=softfp -mfpu=neon'
#endif
-/*
- * Pull in the reference implementations while instructing GCC (through
- * -ftree-vectorize) to attempt to exploit implicit parallelism and emit
- * NEON instructions.
- */
-#ifdef CONFIG_CC_IS_GCC
-#pragma GCC optimize "tree-vectorize"
-#endif
-
-#pragma GCC diagnostic ignored "-Wunused-variable"
#include <asm-generic/xor.h>
struct xor_block_template const xor_block_neon_inner = {
--
2.29.2
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next prev parent reply other threads:[~2020-11-12 21:23 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 21:24 [PATCH v2 0/2] xor-neon: Remove GCC warn & pragmas Adrian Ratiu
2020-11-12 21:24 ` Adrian Ratiu
2020-11-12 21:24 ` [PATCH v2 1/2] arm: lib: xor-neon: remove unnecessary GCC < 4.6 warning Adrian Ratiu
2020-11-12 21:24 ` Adrian Ratiu
2020-11-12 21:38 ` Nick Desaulniers
2020-11-12 21:38 ` Nick Desaulniers
2020-11-13 7:49 ` Ard Biesheuvel
2020-11-13 7:49 ` Ard Biesheuvel
2020-11-13 11:07 ` Adrian Ratiu
2020-11-13 11:07 ` Adrian Ratiu
2020-11-13 11:41 ` Ard Biesheuvel
2020-11-13 11:41 ` Ard Biesheuvel
2020-11-13 11:59 ` Adrian Ratiu
2020-11-13 11:59 ` Adrian Ratiu
2020-11-12 21:24 ` Adrian Ratiu [this message]
2020-11-12 21:24 ` [PATCH v2 2/2] arm: lib: xor-neon: move pragma options to makefile Adrian Ratiu
2020-11-12 21:40 ` Nick Desaulniers
2020-11-12 21:40 ` Nick Desaulniers
2020-11-12 21:50 ` Nathan Chancellor
2020-11-12 21:50 ` Nathan Chancellor
2020-11-13 7:50 ` Ard Biesheuvel
2020-11-13 7:50 ` Ard Biesheuvel
2020-11-13 11:17 ` Adrian Ratiu
2020-11-13 11:17 ` Adrian Ratiu
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