Re: 2.4.4-pre6 does not compile

From: Russell King (rmk@arm.linux.org.uk)
Date: Sat Apr 21 2001 - 16:34:30 EDT

  • Next message: Philip Blundell: "Re: 2.4.4-pre6 does not compile"

    On Sat, Apr 21, 2001 at 10:17:28PM +0200, Jochen Striepe wrote:
    > 2.4.4-pre6 actually is the 4th 2.4.4pre-Patch that does not compile
    > without further patching on my system. :-(
    > rwsem.o(.text+0x30): undefined reference to `__builtin_expect'
    > rwsem.o(.text+0x73): undefined reference to `__builtin_expect'

    Its because you're using a version of gcc which doesn't have
    __builtin_expect (eg, egcs 1.1.2, some versions of gcc 2.95).
    I'm told that gcc 2.95.[12] are not suitable for kernel compilation...

    I've currently got the following in my tree (sorry, no diff since I've
    got other changes in this file). lib/rwsem.c, line 9, add:

    #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 96)
    #define __builtin_expect(exp,c) (exp)
    #endif

    I'm not sure if this is correct, or which compilers work, which don't
    (so don't anyone go and drop it into Linus/Alans kernels), but it
    seems to work for me. 

    --
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

    -
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