Four months ago a debate on the lkml suggested that support for GCC 2.95 would be around for a long time [story], but a more recent thread suggests otherwise. 2.6 maintainer Andrew Morton put together a small patch to remove support for 2.95, and discussion continued to explore which versions of GCC 3.x should be supported. Andrew explained:

"2.95.x is basically buggered at present. There's one scsi driver which doesn't compile due to weird __VA_ARGS__ tricks and the rather useful scsi/sd.c is currently getting an ICE. None of the new SAS code compiles, due to extensive use of anonymous unions. The V4L guys are very good at exploiting the gcc-2.95.x macro expansion bug (_why_ does each driver need to implement its own debug macros?) and various people keep on sneaking in anonymous unions.

"It's time to give up on it and just drink more coffee or play more tetris or something, I'm afraid."

From: Andi Kleen [email blocked]
To: Ingo Molnar [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 08:58:35 +0100

> - i introduced a 'type-sensitive' macro wrapper that switches down() 
>   (and the other APIs) to either to the assembly variant (if the 
>   variable's type is struct compat_semaphore), or switches it to the new 
>   generic mutex (if the type is struct semaphore), at build-time. There 
>   is no runtime overhead due to this build-time-switching.

Didn't that drop compatibility with 2.95?  The necessary builtins
are only in 3.x. 

Not that I'm not in favour - I would like to use C99 everywhere 
and it would get of the ugly spinlock workaround for i386
and x86-64 doesn't support earlier compilers anyways - 
but others might not agree.

-Andi



From: Andrew Morton [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 00:42:57 -0800

Andi Kleen [email blocked] wrote:
>
> > - i introduced a 'type-sensitive' macro wrapper that switches down() 
> >   (and the other APIs) to either to the assembly variant (if the 
> >   variable's type is struct compat_semaphore), or switches it to the new 
> >   generic mutex (if the type is struct semaphore), at build-time. There 
> >   is no runtime overhead due to this build-time-switching.
> 
> Didn't that drop compatibility with 2.95?  The necessary builtins
> are only in 3.x. 
> 
> Not that I'm not in favour - I would like to use C99 everywhere 
> and it would get of the ugly spinlock workaround for i386
> and x86-64 doesn't support earlier compilers anyways - 
> but others might not agree.
> 

2.95.x is basically buggered at present.  There's one scsi driver which
doesn't compile due to weird __VA_ARGS__ tricks and the rather useful
scsi/sd.c is currently getting an ICE.  None of the new SAS code compiles,
due to extensive use of anonymous unions.  The V4L guys are very good at
exploiting the gcc-2.95.x macro expansion bug (_why_ does each driver need
to implement its own debug macros?) and various people keep on sneaking in
anonymous unions.

It's time to give up on it and just drink more coffee or play more tetris
or something, I'm afraid.



From: Andi Kleen [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 09:49:26 +0100

> It's time to give up on it and just drink more coffee or play more tetris
> or something, I'm afraid.

Or start using icecream (http://wiki.kde.org/icecream) 

Anyways cool.  Gratulations. Can you please apply the following patch then? 

Remove -Wdeclaration-after-statement

Now that gcc 2.95 is not supported anymore it's ok to use C99
style mixed declarations everywhere.

Signed-off-by: Andi Kleen [email blocked]

Index: linux/Makefile
===================================================================
--- linux/Makefile
+++ linux/Makefile
@@ -535,9 +535,6 @@ include $(srctree)/arch/$(ARCH)/Makefile
 NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 
-# warn about C99 declaration after statement
-CFLAGS += $(call cc-option,-Wdeclaration-after-statement,)
-
 # disable pointer signedness warnings in gcc 4.0
 CFLAGS += $(call cc-option,-Wno-pointer-sign,)
 


From: Andrew Morton [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 01:01:26 -0800

Andi Kleen [email blocked] wrote:
>
> Can you please apply the following patch then? 
> 
>  Remove -Wdeclaration-after-statement

OK.

Thus far I have this:

From: Andrew Morton [email blocked]

There's one scsi driver which doesn't compile due to weird __VA_ARGS__ tricks
and the rather useful scsi/sd.c is currently getting an ICE.  None of the new
SAS code compiles, due to extensive use of anonymous unions.  The V4L guys are
very good at exploiting the gcc-2.95.x macro expansion bug (_why_ does each
driver need to implement its own debug macros?) and various people keep on
sneaking in anonymous unions.

Plus anonymous unions are rather useful.

Signed-off-by: Andrew Morton [email blocked]
---

 dev/null                 |   29 -----------------------------
 include/linux/compiler.h |    2 --
 init/main.c              |    7 +------
 3 files changed, 1 insertion(+), 37 deletions(-)

diff -puN init/main.c~abandon-gcc-295x init/main.c
--- devel/init/main.c~abandon-gcc-295x	2005-12-13 00:48:17.000000000 -0800
+++ devel-akpm/init/main.c	2005-12-13 00:48:17.000000000 -0800
@@ -58,11 +58,6 @@
  * This is one of the first .c files built. Error out early
  * if we have compiler trouble..
  */
-#if __GNUC__ == 2 && __GNUC_MINOR__ == 96
-#ifdef CONFIG_FRAME_POINTER
-#error This compiler cannot compile correctly with frame pointers enabled
-#endif
-#endif
 
 #ifdef CONFIG_X86_LOCAL_APIC
 #include <asm/smp.h>
@@ -74,7 +69,7 @@
  * To avoid associated bogus bug reports, we flatly refuse to compile
  * with a gcc that is known to be too old from the very beginning.
  */
-#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
+#if __GNUC__ < 3
 #error Sorry, your GCC is too old. It builds incorrect kernels.
 #endif
 
diff -L include/linux/compiler-gcc2.h -puN include/linux/compiler-gcc2.h~abandon-gcc-295x /dev/null
--- devel/include/linux/compiler-gcc2.h
+++ /dev/null	2003-09-15 06:40:47.000000000 -0700
@@ -1,29 +0,0 @@
-/* Never include this file directly.  Include <linux/compiler.h> instead.  */
-
-/* These definitions are for GCC v2.x.  */
-
-/* Somewhere in the middle of the GCC 2.96 development cycle, we implemented
-   a mechanism by which the user can annotate likely branch directions and
-   expect the blocks to be reordered appropriately.  Define __builtin_expect
-   to nothing for earlier compilers.  */
-#include <linux/compiler-gcc.h>
-
-#if __GNUC_MINOR__ < 96
-# define __builtin_expect(x, expected_value) (x)
-#endif
-
-#define __attribute_used__	__attribute__((__unused__))
-
-/*
- * The attribute `pure' is not implemented in GCC versions earlier
- * than 2.96.
- */
-#if __GNUC_MINOR__ >= 96
-# define __attribute_pure__	__attribute__((pure))
-# define __attribute_const__	__attribute__((__const__))
-#endif
-
-/* GCC 2.95.x/2.96 recognize __va_copy, but not va_copy. Actually later GCC's
- * define both va_copy and __va_copy, but the latter may go away, so limit this
- * to this header */
-#define va_copy			__va_copy
diff -puN include/linux/compiler.h~abandon-gcc-295x include/linux/compiler.h
--- devel/include/linux/compiler.h~abandon-gcc-295x	2005-12-13 00:48:17.000000000 -0800
+++ devel-akpm/include/linux/compiler.h	2005-12-13 00:48:17.000000000 -0800
@@ -42,8 +42,6 @@ extern void __chk_io_ptr(void __iomem *)
 # include <linux/compiler-gcc4.h>
 #elif __GNUC__ == 3
 # include <linux/compiler-gcc3.h>
-#elif __GNUC__ == 2
-# include <linux/compiler-gcc2.h>
 #else
 # error Sorry, your compiler is too old/not recognized.
 #endif
_



From: Andrew Morton [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 01:02:33 -0800

Andrew Morton [email blocked] wrote:
>
> Thus far I have this:
>

And this:


From: Andrew Morton[email blocked]

Remove various things which were checking for gcc-1.x and gcc-2.x compilers.


Signed-off-by: Andrew Morton [email blocked]
---

 arch/arm/kernel/asm-offsets.c     |    7 +------
 arch/arm26/kernel/asm-offsets.c   |    7 -------
 arch/ia64/kernel/head.S           |    2 +-
 arch/ia64/kernel/ia64_ksyms.c     |    2 +-
 arch/ia64/oprofile/backtrace.c    |    2 +-
 drivers/md/raid0.c                |    6 ------
 fs/xfs/xfs_log.h                  |    8 +-------
 include/asm-um/rwsem.h            |    4 ----
 include/asm-v850/unistd.h         |   18 ------------------
 include/linux/seccomp.h           |    6 +-----
 include/linux/spinlock_types_up.h |   14 --------------
 11 files changed, 6 insertions(+), 70 deletions(-)

diff -puN drivers/md/raid0.c~remove-gcc2-checks drivers/md/raid0.c
--- devel/drivers/md/raid0.c~remove-gcc2-checks	2005-12-13 00:51:14.000000000 -0800
+++ devel-akpm/drivers/md/raid0.c	2005-12-13 00:51:35.000000000 -0800
@@ -307,9 +307,6 @@ static int raid0_run (mddev_t *mddev)
 	printk("raid0 : conf->hash_spacing is %llu blocks.\n",
 		(unsigned long long)conf->hash_spacing);
 	{
-#if __GNUC__ < 3
-		volatile
-#endif
 		sector_t s = mddev->array_size;
 		sector_t space = conf->hash_spacing;
 		int round;
@@ -440,9 +437,6 @@ static int raid0_make_request (request_q
  
 
 	{
-#if __GNUC__ < 3
-		volatile
-#endif
 		sector_t x = block >> conf->preshift;
 		sector_div(x, (u32)conf->hash_spacing);
 		zone = conf->hash_table[x];
diff -puN fs/xfs/xfs_log.h~remove-gcc2-checks fs/xfs/xfs_log.h
--- devel/fs/xfs/xfs_log.h~remove-gcc2-checks	2005-12-13 00:51:14.000000000 -0800
+++ devel-akpm/fs/xfs/xfs_log.h	2005-12-13 00:52:10.000000000 -0800
@@ -30,13 +30,7 @@
  * By comparing each compnent, we don't have to worry about extra
  * endian issues in treating two 32 bit numbers as one 64 bit number
  */
-static
-#if defined(__GNUC__) && (__GNUC__ == 2) && ( (__GNUC_MINOR__ == 95) || (__GNUC_MINOR__ == 96))
-__attribute__((unused))	/* gcc 2.95, 2.96 miscompile this when inlined */
-#else
-__inline__
-#endif
-xfs_lsn_t	_lsn_cmp(xfs_lsn_t lsn1, xfs_lsn_t lsn2)
+static inline xfs_lsn_t	_lsn_cmp(xfs_lsn_t lsn1, xfs_lsn_t lsn2)
 {
 	if (CYCLE_LSN(lsn1) != CYCLE_LSN(lsn2))
 		return (CYCLE_LSN(lsn1)<CYCLE_LSN(lsn2))? -999 : 999;
diff -puN arch/arm/kernel/asm-offsets.c~remove-gcc2-checks arch/arm/kernel/asm-offsets.c
--- devel/arch/arm/kernel/asm-offsets.c~remove-gcc2-checks	2005-12-13 00:51:14.000000000 -0800
+++ devel-akpm/arch/arm/kernel/asm-offsets.c	2005-12-13 00:53:27.000000000 -0800
@@ -23,18 +23,13 @@
 #error Sorry, your compiler targets APCS-26 but this kernel requires APCS-32
 #endif
 /*
- * GCC 2.95.1, 2.95.2: ignores register clobber list in asm().
  * GCC 3.0, 3.1: general bad code generation.
  * GCC 3.2.0: incorrect function argument offset calculation.
  * GCC 3.2.x: miscompiles NEW_AUX_ENT in fs/binfmt_elf.c
  *            (http://gcc.gnu.org/PR8896) and incorrect structure
  *	      initialisation in fs/jffs2/erase.c
  */
-#if __GNUC__ < 2 || \
-   (__GNUC__ == 2 && __GNUC_MINOR__ < 95) || \
-   (__GNUC__ == 2 && __GNUC_MINOR__ == 95 && __GNUC_PATCHLEVEL__ != 0 && \
-					     __GNUC_PATCHLEVEL__ < 3) || \
-   (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
+#if __GNUC__ < 2 || (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
 #error Your compiler is too buggy; it is known to miscompile kernels.
 #error    Known good compilers: 2.95.3, 2.95.4, 2.96, 3.3
 #endif
diff -puN arch/arm26/kernel/asm-offsets.c~remove-gcc2-checks arch/arm26/kernel/asm-offsets.c
--- devel/arch/arm26/kernel/asm-offsets.c~remove-gcc2-checks	2005-12-13 00:51:14.000000000 -0800
+++ devel-akpm/arch/arm26/kernel/asm-offsets.c	2005-12-13 00:53:47.000000000 -0800
@@ -25,13 +25,6 @@
 #if defined(__APCS_32__) && defined(CONFIG_CPU_26)
 #error Sorry, your compiler targets APCS-32 but this kernel requires APCS-26
 #endif
-#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 95)
-#error Sorry, your compiler is known to miscompile kernels.  Only use gcc 2.95.3 and later.
-#endif
-#if __GNUC__ == 2 && __GNUC_MINOR__ == 95
-/* shame we can't detect the .1 or .2 releases */
-#warning GCC 2.95.2 and earlier miscompiles kernels.
-#endif
 
 /* Use marker if you need to separate the values later */
 
diff -puN arch/ia64/kernel/ia64_ksyms.c~remove-gcc2-checks arch/ia64/kernel/ia64_ksyms.c
--- devel/arch/ia64/kernel/ia64_ksyms.c~remove-gcc2-checks	2005-12-13 00:51:14.000000000 -0800
+++ devel-akpm/arch/ia64/kernel/ia64_ksyms.c	2005-12-13 00:54:02.000000000 -0800
@@ -103,7 +103,7 @@ EXPORT_SYMBOL(unw_init_running);
 
 #ifdef ASM_SUPPORTED
 # ifdef CONFIG_SMP
-#  if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
+#  if (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
 /*
  * This is not a normal routine and we don't want a function descriptor for it, so we use
  * a fake declaration here.
diff -puN arch/ia64/kernel/head.S~remove-gcc2-checks arch/ia64/kernel/head.S
--- devel/arch/ia64/kernel/head.S~remove-gcc2-checks	2005-12-13 00:51:15.000000000 -0800
+++ devel-akpm/arch/ia64/kernel/head.S	2005-12-13 00:54:10.000000000 -0800
@@ -1060,7 +1060,7 @@ SET_REG(b5);
 	 * the clobber lists for spin_lock() in include/asm-ia64/spinlock.h.
 	 */
 
-#if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
+#if (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
 
 GLOBAL_ENTRY(ia64_spinlock_contention_pre3_4)
 	.prologue
diff -puN arch/ia64/oprofile/backtrace.c~remove-gcc2-checks arch/ia64/oprofile/backtrace.c
--- devel/arch/ia64/oprofile/backtrace.c~remove-gcc2-checks	2005-12-13 00:51:15.000000000 -0800
+++ devel-akpm/arch/ia64/oprofile/backtrace.c	2005-12-13 00:54:16.000000000 -0800
@@ -32,7 +32,7 @@ typedef struct
 	u64 *prev_pfs_loc;	/* state for WAR for old spinlock ool code */
 } ia64_backtrace_t;
 
-#if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
+#if (__GNUC__ == 3 && __GNUC_MINOR__ < 3)
 /*
  * Returns non-zero if the PC is in the spinlock contention out-of-line code
  * with non-standard calling sequence (on older compilers).
diff -puN include/linux/spinlock_types_up.h~remove-gcc2-checks include/linux/spinlock_types_up.h
--- devel/include/linux/spinlock_types_up.h~remove-gcc2-checks	2005-12-13 00:51:15.000000000 -0800
+++ devel-akpm/include/linux/spinlock_types_up.h	2005-12-13 00:55:14.000000000 -0800
@@ -22,30 +22,16 @@ typedef struct {
 
 #else
 
-/*
- * All gcc 2.95 versions and early versions of 2.96 have a nasty bug
- * with empty initializers.
- */
-#if (__GNUC__ > 2)
 typedef struct { } raw_spinlock_t;
 
 #define __RAW_SPIN_LOCK_UNLOCKED { }
-#else
-typedef struct { int gcc_is_buggy; } raw_spinlock_t;
-#define __RAW_SPIN_LOCK_UNLOCKED (raw_spinlock_t) { 0 }
-#endif
 
 #endif
 
-#if (__GNUC__ > 2)
 typedef struct {
 	/* no debug version on UP */
 } raw_rwlock_t;
 
 #define __RAW_RW_LOCK_UNLOCKED { }
-#else
-typedef struct { int gcc_is_buggy; } raw_rwlock_t;
-#define __RAW_RW_LOCK_UNLOCKED (raw_rwlock_t) { 0 }
-#endif
 
 #endif /* __LINUX_SPINLOCK_TYPES_UP_H */
diff -puN include/linux/seccomp.h~remove-gcc2-checks include/linux/seccomp.h
--- devel/include/linux/seccomp.h~remove-gcc2-checks	2005-12-13 00:51:15.000000000 -0800
+++ devel-akpm/include/linux/seccomp.h	2005-12-13 00:55:25.000000000 -0800
@@ -26,11 +26,7 @@ static inline int has_secure_computing(s
 
 #else /* CONFIG_SECCOMP */
 
-#if (__GNUC__ > 2)
-  typedef struct { } seccomp_t;
-#else
-  typedef struct { int gcc_is_buggy; } seccomp_t;
-#endif
+typedef struct { } seccomp_t;
 
 #define secure_computing(x) do { } while (0)
 /* static inline to preserve typechecking */
diff -puN include/asm-um/rwsem.h~remove-gcc2-checks include/asm-um/rwsem.h
--- devel/include/asm-um/rwsem.h~remove-gcc2-checks	2005-12-13 00:51:15.000000000 -0800
+++ devel-akpm/include/asm-um/rwsem.h	2005-12-13 00:55:41.000000000 -0800
@@ -1,10 +1,6 @@
 #ifndef __UM_RWSEM_H__
 #define __UM_RWSEM_H__
 
-#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 96)
-#define __builtin_expect(exp,c) (exp)
-#endif
-
 #include "asm/arch/rwsem.h"
 
 #endif
diff -puN include/asm-v850/unistd.h~remove-gcc2-checks include/asm-v850/unistd.h
--- devel/include/asm-v850/unistd.h~remove-gcc2-checks	2005-12-13 00:51:15.000000000 -0800
+++ devel-akpm/include/asm-v850/unistd.h	2005-12-13 00:56:07.000000000 -0800
@@ -241,9 +241,6 @@
 /* User programs sometimes end up including this header file
    (indirectly, via uClibc header files), so I'm a bit nervous just
    including <linux/compiler.h>.  */
-#if !defined(__builtin_expect) && __GNUC__ == 2 && __GNUC_MINOR__ < 96
-#define __builtin_expect(x, expected_value) (x)
-#endif
 
 #define __syscall_return(type, res)					      \
   do {									      \
@@ -346,20 +343,6 @@ type name (atype a, btype b, ctype c, dt
   __syscall_return (type, __ret);					      \
 }
 
-#if __GNUC__ < 3
-/* In older versions of gcc, `asm' statements with more than 10
-   input/output arguments produce a fatal error.  To work around this
-   problem, we use two versions, one for gcc-3.x and one for earlier
-   versions of gcc (the `earlier gcc' version doesn't work with gcc-3.x
-   because gcc-3.x doesn't allow clobbers to also be input arguments).  */
-#define __SYSCALL6_TRAP(syscall, ret, a, b, c, d, e, f)			      \
-  __asm__ __volatile__ ("trap " SYSCALL_LONG_TRAP			      \
-			: "=r" (ret), "=r" (syscall)			      \
-			: "1" (syscall),				      \
-			"r" (a), "r" (b), "r" (c), "r" (d),		      \
- 			"r" (e), "r" (f)				      \
-			: SYSCALL_CLOBBERS, SYSCALL_ARG4, SYSCALL_ARG5);
-#else /* __GNUC__ >= 3 */
 #define __SYSCALL6_TRAP(syscall, ret, a, b, c, d, e, f)			      \
   __asm__ __volatile__ ("trap " SYSCALL_LONG_TRAP			      \
 			: "=r" (ret), "=r" (syscall),			      \
@@ -368,7 +351,6 @@ type name (atype a, btype b, ctype c, dt
 			"r" (a), "r" (b), "r" (c), "r" (d),		      \
 			"2" (e), "3" (f)				      \
 			: SYSCALL_CLOBBERS);
-#endif
 
 #define _syscall6(type, name, atype, a, btype, b, ctype, c, dtype, d, etype, e, ftype, f) \
 type name (atype a, btype b, ctype c, dtype d, etype e, ftype f)	      \
_


From: Linus Torvalds [email blocked]
To: Andi Kleen [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 08:16:39 -0800 (PST)



On Tue, 13 Dec 2005, Andi Kleen wrote:
> 
> Remove -Wdeclaration-after-statement

Please don't.

It's a coding style issue. We put our variable declarations where people 
can _find_ them, not in random places in the code.

Putting variables in the middle of code only improves readability when you 
have messy code. 

Now, one feature that _may_ be worth it is the loop counter thing:

	for (int i = 10; i; i--)
		...

kind of syntax actually makes sense and is a real feature (it makes "i" 
local to the loop, and can actually help people avoid bugs - you can't use 
"i" by mistake after the loop).

But I think you need "--std=c99" for gcc to take that.

			Linus


From: Andrew Morton [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 01:15:40 -0800

Andi Kleen [email blocked] wrote:
>
> On Tue, Dec 13, 2005 at 01:01:26AM -0800, Andrew Morton wrote:
> > Andi Kleen [email blocked] wrote:
> > >
> > > Can you please apply the following patch then? 
> > > 
> > >  Remove -Wdeclaration-after-statement
> > 
> > OK.
> > 
> > Thus far I have this:
> 
> Would it be possible to drop support for gcc 3.0 too? 

Spose so - I don't know what people are using out there.

> AFAIK it has never been widely used. If we assume 3.1+ minimum it has the 
> advantage that named assembly arguments work, which make
> the inline assembly often a lot easier to read and maintain.

There are a few places in the tree which refuse to compile with 3.1 and 3.2.



From: Andi Kleen [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 10:24:37 +0100

> Spose so - I don't know what people are using out there.

I don't think it was shipped in major distros at least (AFAIK) 
They all went from 2.95 to 3.1/3.2 

Perhaps stick an error for 3.0 in and wait if people are complaining? 

> 
> > AFAIK it has never been widely used. If we assume 3.1+ minimum it has the 
> > advantage that named assembly arguments work, which make
> > the inline assembly often a lot easier to read and maintain.
> 
> There are a few places in the tree which refuse to compile with 3.1 and 3.2.

Really? Which ones? 

Haven't seen that and I still use 3.2 occasionally (it's the default
compiler on SLES9 and I believe on RHEL3 too)  

-Andi



From: Andrew Morton [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 01:44:37 -0800

Andi Kleen [email blocked] wrote:
>
> > There are a few places in the tree which refuse to compile with 3.1 and 3.2.
> 
>  Really? Which ones? 

grep for __GNUC_MINOR__



From: Andi Kleen [email blocked]
Subject: Re: [PATCH 1/19] MUTEX: Introduce simple mutex implementation
Date:	Tue, 13 Dec 2005 10:49:33 +0100

On Tue, Dec 13, 2005 at 01:44:37AM -0800, Andrew Morton wrote:
> Andi Kleen [email blocked] wrote:
> >
> > > There are a few places in the tree which refuse to compile with 3.1 and 3.2.
> > 
> >  Really? Which ones? 
> 
> grep for __GNUC_MINOR__

I reviewed them and I didn't find any that refused 3.2 or 3.3.

Some architectures have special code for old gccs, but nothing
generic.

-Andi

• Archive of above thread
• KernelTrap interview with Andrew Morton