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gcc vzeroupper

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    Authored by Henrik Gramner

    gcc (Debian 14.2.0-17) 14.2.0

    gcc -mavx -O1:

    0000000000000000 <copy>:
   0:   c5 fe 6f 06             vmovdqu ymm0,YMMWORD PTR [rsi]
   4:   c5 fe 7f 07             vmovdqu YMMWORD PTR [rdi],ymm0
   8:   c3                      ret

0000000000000009 <zero>:
   9:   c5 f9 ef c0             vpxor  xmm0,xmm0,xmm0
   d:   c5 fe 7f 07             vmovdqu YMMWORD PTR [rdi],ymm0
  11:   c3                      ret

    gcc -mavx -O2:

    0000000000000000 <copy>:
   0:   c5 fe 6f 06             vmovdqu ymm0,YMMWORD PTR [rsi]
   4:   c5 fe 7f 07             vmovdqu YMMWORD PTR [rdi],ymm0
   8:   c5 f8 77                vzeroupper
   b:   c3                      ret

0000000000000010 <zero>:
  10:   c5 f9 ef c0             vpxor  xmm0,xmm0,xmm0
  14:   c5 fe 7f 07             vmovdqu YMMWORD PTR [rdi],ymm0
  18:   c5 f8 77                vzeroupper
  1b:   c3                      ret
    Edited
    test.c 140 B
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    #include <string.h>

void copy(void *dst, void *src) {
    memcpy(dst, src, 32);
}

void zero(void *dst) {
    memset(dst, 0, 32);
}
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