Re: [patch 2/7] enable unit-at-a-time optimisations for gcc4

Sam Ravnborg
2006-01-07T12:00:21Z

On Sat, Jan 07, 2006 at 02:13:10AM -0800, Andrew Morton wrote:
>
> Only sparc64 appears to do that now. If someone wants to reintroduce such
> a dopey thing then they need to remember to reevaluate GCC_VERSION
> afterwards? Like:

Dropping GCC_VERSION is cleaner. In a few cases we do one extra call to
gcc during first phase of compilation. That does not matter.
Like this:

Documentation/kbuild/makefiles.txt | 4 ++--
arch/i386/Makefile | 4 ++--
arch/ia64/Makefile | 5 ++---
arch/powerpc/Makefile | 6 ++----
arch/ppc/Makefile | 3 +--
5 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index d802ce8..443230b 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -1033,9 +1033,9 @@ When kbuild executes the following steps

Example:
#arch/i386/Makefile
- GCC_VERSION := $(call cc-version)
cflags-y += $(shell \
- if [ $(GCC_VERSION) -ge 0300 ] ; then echo "-mregparm=3"; fi ;)
+ if [ $(call cc-version) -ge 0300 ] ; then \
+ echo "-mregparm=3"; fi ;)

In the above example -mregparm=3 is only used for gcc version greater
than or equal to gcc 3.0.
diff --git a/arch/i386/Makefile b/arch/i386/Makefile
index d121ea1..76fcf7c 100644
--- a/arch/i386/Makefile
+++ b/arch/i386/Makefile
@@ -39,8 +39,8 @@ include $(srctree)/arch/i386/Makefile.cp

# -mregparm=3 works ok on gcc-3.0 and later
#
-GCC_VERSION := $(call cc-version)
-cflags-$(CONFIG_REGPARM) += $(shell if [ $(GCC_VERSION) -ge 0300 ] ; then echo "-mregparm=3"; fi ;)
+cflags-$(CONFIG_REGPARM) += $(shell if [ $(call cc-version) -ge 0300 ] ; then \
+ echo "-mregparm=3"; fi ;)

# Disable unit-at-a-time mode, it makes gcc use a lot more stack
# due to the lack of sharing of stacklots.
diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
index 67932ad..88a134e 100644
--- a/arch/ia64/Makefile
+++ b/arch/ia64/Makefile
@@ -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)")

@@ -37,11 +36,11 @@ $(error Sorry, you need a newer version
ftp://ftp.hpl.hp.com/pub/linux-ia64/gas-030124.tar.gz)
endif

-ifneq ($(shell if [ $(GCC_VERSION) -lt 0300 ] ; then echo "bad"; fi ;),)
+ifneq ($(shell if [ $(call cc-version) -lt 0300 ] ; then echo "bad"; fi ;),)
$(error Sorry, your compiler is too old. GCC v2.96 is known to generate bad code.)
endif

-ifeq ($(GCC_VERSION),0304)
+ifeq ($(call cc-version),0304)
cflags-$(CONFIG_ITANIUM) += -mtune=merced
cflags-$(CONFIG_MCKINLEY) += -mtune=mckinley
endif
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index a13eb57..b98f11b 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -76,8 +76,7 @@ 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)
+GCC_BROKEN_VEC := $(shell if [ $(call cc-version) -lt 0400 ] ; then echo "y"; fi)

ifeq ($(CONFIG_POWER4_ONLY),y)
ifeq ($(CONFIG_ALTIVEC),y)
@@ -189,10 +188,9 @@ 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 "$(GCC_VERSION)" = "0304" ; then \
+ @if test "$(call cc-version)" = "0304" ; then \
if ! /bin/echo mftb 5 | $(AS) -v -mppc -many -o $(TOUT) >/dev/null 2>&1 ; then \
echo -n '*** ${VERSION}.${PATCHLEVEL} kernels no longer build '; \
echo 'correctly with gcc-3.4 and your version of binutils.'; \
diff --git a/arch/ppc/Makefile b/arch/ppc/Makefile
index e719a49..98e940b 100644
--- a/arch/ppc/Makefile
+++ b/arch/ppc/Makefile
@@ -128,10 +128,9 @@ 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 "$(GCC_VERSION)" = "0304" ; then \
+ @if test "$(call cc-version)" = "0304" ; then \
if ! /bin/echo mftb 5 | $(AS) -v -mppc -many -o $(TOUT) >/dev/null 2>&1 ; then \
echo -n '*** ${VERSION}.${PATCHLEVEL} kernels no longer build '; \
echo 'correctly with gcc-3.4 and your version of binutils.'; \