Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030368AbWAGJIU (ORCPT ); Sat, 7 Jan 2006 04:08:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030375AbWAGJIU (ORCPT ); Sat, 7 Jan 2006 04:08:20 -0500 Received: from smtp.osdl.org ([65.172.181.4]:1982 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1030368AbWAGJIT (ORCPT ); Sat, 7 Jan 2006 04:08:19 -0500 Date: Sat, 7 Jan 2006 01:07:57 -0800 From: Andrew Morton To: Arjan van de Ven Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, Sam Ravnborg Subject: Re: [patch 2/7] enable unit-at-a-time optimisations for gcc4 Message-Id: <20060107010757.2e853f77.akpm@osdl.org> In-Reply-To: <1136543914.2940.11.camel@laptopd505.fenrus.org> References: <1136543825.2940.8.camel@laptopd505.fenrus.org> <1136543914.2940.11.camel@laptopd505.fenrus.org> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4934 Lines: 116 Arjan van de Ven wrote: > > allow gcc4 compilers to optimize unit-at-a-time. > > This flag enables gcc to "see" the entire C file before making optimisation > decisions such as inline, which results in gcc making better decisions. One > of the immediate effects of this is that static functions that are used only > once now get inlined. > > gcc 3.4 has this flag as well, however gcc 3.x have a problem with inlining > and stacks and as a result, enabling this flag there would cause excessive > and unacceptable stack use. This problem is fixed in the gcc 4.x series. > The x86-64 architecture already enables this feature so it's well tested > already. bix:/usr/src/25> make vmlinux /bin/sh: line 1: [: -lt: unary operator expected Because GCC_VERSION hasn't been initialised at this stage. Is there any reason why we can't do this? From: Andrew Morton Set GCC_VERSION up-front rather than in arch Makefiles. This reduces ordering problems and generally consolidates things. Cc: Sam Ravnborg Cc: Arjan van de Ven Signed-off-by: Andrew Morton --- Makefile | 2 +- arch/ia64/Makefile | 1 - arch/parisc/Makefile | 4 ---- arch/powerpc/Makefile | 2 -- arch/ppc/Makefile | 1 - 5 files changed, 1 insertion(+), 9 deletions(-) diff -puN arch/ia64/Makefile~kbuild-call-gcc_version-earlier arch/ia64/Makefile --- devel/arch/ia64/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800 +++ devel-akpm/arch/ia64/Makefile 2006-01-07 01:05:39.000000000 -0800 @@ -25,7 +25,6 @@ cflags-y := -pipe $(EXTRA) -ffixed-r13 - -falign-functions=32 -frename-registers -fno-optimize-sibling-calls CFLAGS_KERNEL := -mconstant-gp -GCC_VERSION := $(call cc-version) GAS_STATUS = $(shell $(srctree)/arch/ia64/scripts/check-gas "$(CC)" "$(OBJDUMP)") CPPFLAGS += $(shell $(srctree)/arch/ia64/scripts/toolchain-flags "$(CC)" "$(OBJDUMP)" "$(READELF)") diff -puN arch/parisc/Makefile~kbuild-call-gcc_version-earlier arch/parisc/Makefile --- devel/arch/parisc/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800 +++ devel-akpm/arch/parisc/Makefile 2006-01-07 01:05:39.000000000 -0800 @@ -35,10 +35,6 @@ FINAL_LD=$(CROSS_COMPILE)ld --warn-commo OBJCOPY_FLAGS =-O binary -R .note -R .comment -S -GCC_VERSION := $(call cc-version) -ifneq ($(shell if [ -z $(GCC_VERSION) ] ; then echo "bad"; fi ;),) -$(error Sorry, couldn't find ($(cc-version)).) -endif ifneq ($(shell if [ $(GCC_VERSION) -lt 0303 ] ; then echo "bad"; fi ;),) $(error Sorry, your compiler is too old ($(GCC_VERSION)). GCC v3.3 or above is required.) endif diff -puN arch/powerpc/Makefile~kbuild-call-gcc_version-earlier arch/powerpc/Makefile --- devel/arch/powerpc/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800 +++ devel-akpm/arch/powerpc/Makefile 2006-01-07 01:05:39.000000000 -0800 @@ -76,7 +76,6 @@ LINUXINCLUDE += $(LINUXINCLUDE-y) CHECKFLAGS += -m$(SZ) -D__powerpc__ -D__powerpc$(SZ)__ ifeq ($(CONFIG_PPC64),y) -GCC_VERSION := $(call cc-version) GCC_BROKEN_VEC := $(shell if [ $(GCC_VERSION) -lt 0400 ] ; then echo "y"; fi) ifeq ($(CONFIG_POWER4_ONLY),y) @@ -189,7 +188,6 @@ TOUT := .tmp_gas_check # Ensure this is binutils 2.12.1 (or 2.12.90.0.7) or later for altivec # instructions. # gcc-3.4 and binutils-2.14 are a fatal combination. -GCC_VERSION := $(call cc-version) checkbin: @if test "$(GCC_VERSION)" = "0304" ; then \ diff -puN arch/ppc/Makefile~kbuild-call-gcc_version-earlier arch/ppc/Makefile --- devel/arch/ppc/Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800 +++ devel-akpm/arch/ppc/Makefile 2006-01-07 01:05:39.000000000 -0800 @@ -128,7 +128,6 @@ TOUT := .tmp_gas_check # Ensure this is binutils 2.12.1 (or 2.12.90.0.7) or later for altivec # instructions. # gcc-3.4 and binutils-2.14 are a fatal combination. -GCC_VERSION := $(call cc-version) checkbin: @if test "$(GCC_VERSION)" = "0304" ; then \ diff -puN Makefile~kbuild-call-gcc_version-earlier Makefile --- Makefile~kbuild-call-gcc_version-earlier 2006-01-07 01:05:39.000000000 -0800 +++ devel-akpm/Makefile 2006-01-07 01:05:39.000000000 -0800 @@ -300,7 +300,7 @@ cc-option-align = $(subst -functions=0,, # Usage gcc-ver := $(call cc-version $(CC)) cc-version = $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-version.sh \ $(if $(1), $(1), $(CC))) - +GCC_VERSION := $(call cc-version) # Look for make include files relative to root of kernel src MAKEFLAGS += --include-dir=$(srctree) _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/