I can't see any difference of code by gcc for restrict pointers.

file1

void test (int *a, int *b, int *c)
{
  while (*a)
  {
    *c++ = *a++ + *b++; 
  }
}

file2

void test (int *restrict a, int *restrict b, int *restrict c)
{
  while (*a)
  {
    *c++ = *a++ + *b++;
  }
}

compile with

  gcc -S -std=c99 -masm=intel file1.c
  gcc -S -std=c99 -masm=intel file2.c

file1.s and file2.s both are same, except the .file line, which tells the filename:

    .file   "file1.c"
    .text
    .globl  test
    .type   test, @function
test:
.LFB0:
    .cfi_startproc
    pushq   %rbp
    .cfi_def_cfa_offset 16
    .cfi_offset 6, -16
    movq    %rsp, %rbp
    .cfi_def_cfa_register 6
    movq    %rdi, -8(%rbp)
    movq    %rsi, -16(%rbp)
    movq    %rdx, -24(%rbp)
    jmp .L2
.L3:
    movq    -8(%rbp), %rax
    movl    (%rax), %edx
    movq    -16(%rbp), %rax
    movl    (%rax), %eax
    addl    %eax, %edx
    movq    -24(%rbp), %rax
    movl    %edx, (%rax)
    addq    $4, -24(%rbp)
    addq    $4, -8(%rbp)
    addq    $4, -16(%rbp)
.L2:
    movq    -8(%rbp), %rax
    movl    (%rax), %eax
    testl   %eax, %eax
    jne .L3
    popq    %rbp
    .cfi_def_cfa 7, 8
    ret
    .cfi_endproc
.LFE0:
    .size   test, .-test
    .ident  "GCC: (GNU) 4.6.3 20120306 (Red Hat 4.6.3-2)"
    .section    .note.GNU-stack,"",@progbits

Both of these code read from the memory and then assign the memory location pointed to by a to b. Where i expected the restrict version will not re-read the addresses of a and b, and the addresses of a and b will be incremented in-register and at the end written to memory.

Is there anything wrong i am doing? Or is the selection of the example okay?<

c pointers restrict-qualifier
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