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| Started by | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| First post | 2016-02-18 18:10 +0100 |
| Last post | 2016-02-19 18:10 +0100 |
| Articles | 4 — 2 participants |
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[PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang Arnd Bergmann <arnd@arndb.de> - 2016-02-18 18:10 +0100
Re: [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-02-18 18:40 +0100
Re: [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang Arnd Bergmann <arnd@arndb.de> - 2016-02-19 15:30 +0100
Re: [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-02-19 18:10 +0100
| From | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| Date | 2016-02-18 18:10 +0100 |
| Subject | [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang |
| Message-ID | <r3Afw-lQ-1@gated-at.bofh.it> |
clang ignores the -mfpu=neon flag when building with -march=armv6: In file included from lib/raid6/neon1.c:27: clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled" There is no real need to build the file with -march=armv6 in a multi-CPU enabled kernel, as nothing in here will ever get called on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only improve the code quality. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- arch/arm/lib/Makefile | 2 +- lib/raid6/Makefile | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index d8a780799506..a86c6c8e0648 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -35,7 +35,7 @@ $(obj)/csumpartialcopy.o: $(obj)/csumpartialcopygeneric.S $(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S ifeq ($(CONFIG_KERNEL_MODE_NEON),y) - NEON_FLAGS := -mfloat-abi=softfp -mfpu=neon + NEON_FLAGS := -mfloat-abi=softfp -mfpu=neon -march=armv7-a CFLAGS_xor-neon.o += $(NEON_FLAGS) obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o endif diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile index 3b10a48fa040..4ef3e800fb39 100644 --- a/lib/raid6/Makefile +++ b/lib/raid6/Makefile @@ -23,7 +23,7 @@ endif ifeq ($(CONFIG_KERNEL_MODE_NEON),y) NEON_FLAGS := -ffreestanding ifeq ($(ARCH),arm) -NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon +NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon -march=armv7-a endif ifeq ($(ARCH),arm64) CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only -- 2.7.0
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| From | Nicolas Pitre <nicolas.pitre@linaro.org> |
|---|---|
| Date | 2016-02-18 18:40 +0100 |
| Subject | Re: [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang |
| Message-ID | <r3AIy-yZ-13@gated-at.bofh.it> |
| In reply to | #1337537 |
On Thu, 18 Feb 2016, Arnd Bergmann wrote: > clang ignores the -mfpu=neon flag when building with -march=armv6: > > In file included from lib/raid6/neon1.c:27: > clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled" > > There is no real need to build the file with -march=armv6 in a > multi-CPU enabled kernel, as nothing in here will ever get called > on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only > improve the code quality. Is this enough to override a previous -mfpu for gcc? > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > arch/arm/lib/Makefile | 2 +- > lib/raid6/Makefile | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile > index d8a780799506..a86c6c8e0648 100644 > --- a/arch/arm/lib/Makefile > +++ b/arch/arm/lib/Makefile > @@ -35,7 +35,7 @@ $(obj)/csumpartialcopy.o: $(obj)/csumpartialcopygeneric.S > $(obj)/csumpartialcopyuser.o: $(obj)/csumpartialcopygeneric.S > > ifeq ($(CONFIG_KERNEL_MODE_NEON),y) > - NEON_FLAGS := -mfloat-abi=softfp -mfpu=neon > + NEON_FLAGS := -mfloat-abi=softfp -mfpu=neon -march=armv7-a > CFLAGS_xor-neon.o += $(NEON_FLAGS) > obj-$(CONFIG_XOR_BLOCKS) += xor-neon.o > endif > diff --git a/lib/raid6/Makefile b/lib/raid6/Makefile > index 3b10a48fa040..4ef3e800fb39 100644 > --- a/lib/raid6/Makefile > +++ b/lib/raid6/Makefile > @@ -23,7 +23,7 @@ endif > ifeq ($(CONFIG_KERNEL_MODE_NEON),y) > NEON_FLAGS := -ffreestanding > ifeq ($(ARCH),arm) > -NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon > +NEON_FLAGS += -mfloat-abi=softfp -mfpu=neon -march=armv7-a > endif > ifeq ($(ARCH),arm64) > CFLAGS_REMOVE_neon1.o += -mgeneral-regs-only > -- > 2.7.0 > >
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| From | Arnd Bergmann <arnd@arndb.de> |
|---|---|
| Date | 2016-02-19 15:30 +0100 |
| Message-ID | <r3Uee-6kG-17@gated-at.bofh.it> |
| In reply to | #1337568 |
On Thursday 18 February 2016 12:31:35 Nicolas Pitre wrote: > On Thu, 18 Feb 2016, Arnd Bergmann wrote: > > > clang ignores the -mfpu=neon flag when building with -march=armv6: > > > > In file included from lib/raid6/neon1.c:27: > > clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled" > > > > There is no real need to build the file with -march=armv6 in a > > multi-CPU enabled kernel, as nothing in here will ever get called > > on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only > > improve the code quality. > > Is this enough to override a previous -mfpu for gcc? I did not see any build failures on gcc with this, so I assume it has no effect. I could move the -march=armv7-a in front of -mfpu=neon if you think that would be safer though. Arnd
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| From | Nicolas Pitre <nicolas.pitre@linaro.org> |
|---|---|
| Date | 2016-02-19 18:10 +0100 |
| Subject | Re: [PATCH 1/3] [RESEND] ARM: pass -march=armv7-a when building NEON files with clang |
| Message-ID | <r3WJ4-8m3-9@gated-at.bofh.it> |
| In reply to | #1338231 |
On Fri, 19 Feb 2016, Arnd Bergmann wrote: > On Thursday 18 February 2016 12:31:35 Nicolas Pitre wrote: > > On Thu, 18 Feb 2016, Arnd Bergmann wrote: > > > > > clang ignores the -mfpu=neon flag when building with -march=armv6: > > > > > > In file included from lib/raid6/neon1.c:27: > > > clang/3.8.0/include/arm_neon.h:28:2: error: "NEON support not enabled" > > > > > > There is no real need to build the file with -march=armv6 in a > > > multi-CPU enabled kernel, as nothing in here will ever get called > > > on an ARMv6 CPU. Adding -march=armv7 doesn't hurt and can only > > > improve the code quality. > > > > Is this enough to override a previous -mfpu for gcc? > > I did not see any build failures on gcc with this, so I assume it > has no effect. I could move the -march=armv7-a in front of > -mfpu=neon if you think that would be safer though. I don't know what's safer. That's why I'm asking. :-) Nicolas
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