Skip to content
  • Jesper Nilsson's avatar
    cris: import memset.c from newlib: fixes compile error with newer (pre4.3) gcc · 77a746ce
    Jesper Nilsson authored
    
    
    Adrian Bunk reported the following compile error with a SVN head GCC:
    
    ...
    CC arch/cris/arch-v10/lib/memset.o
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c: In function 'memset':
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:164: error: lvalue required as increment operand
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:165: error: lvalue required as increment operand
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:166: error: lvalue required as increment operand
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:167: error: lvalue required as increment operand
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:185: error: lvalue required as increment operand
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:189: error: lvalue required as increment operand
    /home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/memset.c:192: error: lvalue required as increment operand
    ... etc ...
    
    This is due to the use of the construct:
    
    	*((long*)dst)++ = lc;
    
    Which is no longer legal since casts don't return an lvalue.
    
    The solution is to import the implementation from newlib,
    which is continually autotested together with GCC mainline,
    and uses the construct:
    
    	*(long *) dst = lc; dst += 4;
    
    With this change, the generated code actually shrinks 76 bytes
    since gcc notices that it can use autoincrement for the move
    instruction in CRIS.
    
       text    data     bss     dec     hex filename
        304       0       0     304     130 memset.old.o
       text    data     bss     dec     hex filename
        228       0       0     228      e4 memset.o
    
    Since this is an import of a file from newlib, I'm not touching
    the formatting or correcting any checkpatch errors.
    
    Note also that even if the two files for the CRIS v10 and CRIS v32
    are identical at the moment, it might be possible to tweak the
    CRIS v32 version. Thus, I'm not yet folding them into the same file,
    at least not until we've done some research on it.
    
    Signed-off-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
    Cc: Mikael Starvik <mikael.starvik@axis.com>
    Cc: Adrian Bunk <bunk@stusta.de>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    77a746ce