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short dw_loop(short x)
{
short y = x/9;
short *p = &x;
short n = 4*x;
do {
x += y;
(*p) += 5;
n += 2;
} while (n > 0);
return x;
}
// x in %rdi
// dw_loop:
// movq %rdi, %rdx # %rbx <- x
// movq %rdi, %rcx # %rcx <- x
// idivq $9, %rcx # %rcx (y) <- x / 9
// leaq (,%rdi,4), %rdx # %rdx (n) <- x * 4
// .L2:
// leaq 5(%rbx,%rcx), %rcx # %rbx (x) <- 5 + %rbx (x) + %rcx (y)
// subq $1, %rdx # %rdx (n) <- n - 1
// testq %rdx, %rdx # n > 0 ?
// jg .L2 # if n > 0, goto .L2
// rep; ret
//
// A. x in rbx, y in rcx, n in rdx
// B. The pointer is never used besides incrementing the value at the address. So it is replaced by a incrementing instruction in the loop.
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