wilzbach

#!/usr/bin/env dub
/++ dub.sdl:
name "filter"
dependency "inifiled" version="~>1.0.1"
dependency "dscanner" version="~>0.4.0"
+/

import analysis.config;
import dparse.lexer : StringCache;
import dsymbol.modulecache : ModuleCache;

wilzbach

RandomAccess

ldc -release -O5 -mcpu=native test.d && ./test
reduce!(min,max) = 7 secs, 722 ms, 265 μs, and 4 hnsecs
fold.minMax     = 5 secs, 770 ms, and 427 μs
minmaxElement   = 5 secs, 410 ms, and 31 μs
minmaxElementInPairs = 15 secs, 362 ms, 724 μs, and 3 hnsecs

wilzbach

#!/usr/bin/env rdmd

import std.algorithm, std.array, std.conv, std.mmfile, std.range, std.stdio, std.bigint;

void main(string[] args)
{
    if (args.length < 2)
    {
        writeln("No input file given.");
        return;

wilzbach

With mapping

> ldc -release -O5 -mcpu=native test.d && ./test
reduce!(min,max) = 16 secs, 745 ms, 280 μs, and 1 hnsec
fold.minMax     = 13 secs, 756 ms, 979 μs, and 4 hnsecs
minmaxElement   = 14 secs, 179 ms, 390 μs, and 1 hnsec

wilzbach

> dmd -release -O test.d && ./test
extremum.before = 54 secs, 12 ms, 347 μs, and 9 hnsecs
extremum.after  = 29 secs, 521 ms, 896 μs, and 5 hnsecs

> ldc -release -O3 test.d && ./test
extremum.before = 13 secs, 186 ms, 176 μs, and 4 hnsecs
extremum.after  = 2 secs, 241 ms, 454 μs, and 9 hnsecs

wilzbach

1. Enable the DScanner check

---

In the .dscanner.ini, set the immutable check to enable:

could_be_immutable_check="enabled"

1. Generate a file with all Dscanner warnings

wilzbach

> ldc -O5 -release -boundscheck=off walkBack.d && ./walkBack

walkBack.foreach = 3 secs, 772 ms, 463 μs, and 6 hnsecs
walkBack.while  = 4 secs, 191 ms, 417 μs, and 8 hnsecs

wilzbach

#!/usr/bin/env rdmd

auto parenDiff(S)(S ss)
{
    auto count = 0;
    foreach (s; ss)
    {
        switch (s)
        {
            case '(': count++; break;

wilzbach

> ldc -O5 -release -boundscheck=off test.d && ./test 1 2 8 256 1024 65536

benchmark: 1 (bits: 1)
random.uniform  = 742 ms, 824 μs, and 5 hnsecs
random.bitwise  = 218 ms, 972 μs, and 9 hnsecs
random.uniform.fixed = 592 ms, 647 μs, and 2 hnsecs
benchmark: 2 (bits: 2)
random.uniform  = 746 ms, 839 μs, and 5 hnsecs
random.bitwise  = 497 ms and 189 μs
random.uniform.fixed = 594 ms, 196 μs, and 1 hnsec

wilzbach

import std.algorithm, std.conv, std.datetime, std.functional, std.range, std.stdio, std.traits, std.typecons;

private void doNotOptimizeAway(T)(auto ref T t)
{
    import core.thread : getpid;
    import std.stdio : writeln;
    if(getpid() == 1) {
        writeln(*cast(char*)&t);
    }
}