I've seen a difference in the performance of
std.algorithm.reverse applied on an array compared to home-made
code, so I have written a little test.
Below you see the code, and the asm of the functions, compiled
with DMD 2.060, 32 bit (-O -release -inline).
Feel free to recompile the code you
On Friday, 23 November 2012 at 09:14:20 UTC, bearophile wrote:
I've seen a difference in the performance of
std.algorithm.reverse applied on an array compared to home-made
code, so I have written a little test.
Below you see the code, and the asm of the functions, compiled
with DMD 2.060, 32
On 11/23/2012 1:14 AM, bearophile wrote:
Feel free to recompile the code yourself to see if I have done some mistake :-)
You've got array bounds checking turned on for algorithm.reverse, and you
avoided that in your code by using unchecked pointers.
Walter Bright:
Sorry for the late reply.
You've got array bounds checking turned on for
algorithm.reverse, and you avoided that in your code by using
unchecked pointers.
Right, sorry. This is compiled with the latest DMD 2.061alpha
with -O -release -inline -noboundscheck. I have used the sa
monarch_dodra:
Could you maybe also add this in your study?
void reverseArr(T)(T[] arr) {
for (auto x = arr.ptr, y = &arr[$ - 1]; x < y; )
swap(*x++, *y--);
}
This is the full program:
import core.stdc.stdio: printf;
import std.algorithm: reverse, swap;
void reverseArr(T)(T[] a
On Wednesday, 28 November 2012 at 00:19:33 UTC, bearophile wrote:
dpaste is currently down and I don't have gdc2/dc2 installed
here, so I can't show the asm from those other compilers.
fwiw, here is what LDC produces:
---
_D4test18__T10reverseArrTiZ10reverseArrFAiZv:
lea RAX, QWORD
