Re: GCC performance regression - its memset !

[Falk Hueffner <falk.hueffner@student.uni-tuebingen.de>]

Hi,

while we're at it, when you have a prototype for memset, gcc forgets
about the alignment:

void f1(unsigned long *p) { memset(p, 0, 16); }
#include <string.h>
void f2(unsigned long *p) { memset(p, 0, 16); }

-> (Alpha)

0000000000000000 <f1>:
   0:   08 00 f0 b7     stq     zero,8(a0)
   4:   1f 04 ff 5f     fnop
   8:   00 00 f0 b7     stq     zero,0(a0)
   c:   01 80 fa 6b     ret
0000000000000020 <f2>:
  20:   0f 00 30 2c     ldq_u   t0,15(a0)
  24:   00 00 50 2c     ldq_u   t1,0(a0)
  28:   41 0e 30 48     mskqh   t0,a0,t0
  2c:   0f 00 30 3c     stq_u   t0,15(a0)
  30:   42 06 50 48     mskql   t1,a0,t1
  34:   08 00 f0 3f     stq_u   zero,8(a0)
  38:   00 00 50 3c     stq_u   t1,0(a0)
  3c:   01 80 fa 6b     ret

Is there anything that can be done about that?

        Falk