pidigits: ghc vs gcc

Clang

bash-3.2$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.5.0
Thread model: posix
bash-3.2$ cat > main.c
/* The Computer Language Benchmarks Game
 * http://benchmarksgame.alioth.debian.org/
 *
 * Contributed by Mr Ledrug
*/

#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>

mpz_t tmp1, tmp2, acc, den, num;
typedef unsigned int ui;

ui extract_digit(ui nth) {
   // joggling between tmp1 and tmp2, so GMP won't have to use temp buffers
   mpz_mul_ui(tmp1, num, nth);
   mpz_add(tmp2, tmp1, acc);
   mpz_tdiv_q(tmp1, tmp2, den);

   return mpz_get_ui(tmp1);
}

void eliminate_digit(ui d) {
   mpz_submul_ui(acc, den, d);
   mpz_mul_ui(acc, acc, 10);
   mpz_mul_ui(num, num, 10);
}

void next_term(ui k) {
   ui k2 = k * 2U + 1U;

   mpz_addmul_ui(acc, num, 2U);
   mpz_mul_ui(acc, acc, k2);
   mpz_mul_ui(den, den, k2);
   mpz_mul_ui(num, num, k);
}

int main(int argc, char **argv) {
   ui d, k, i;
   int n = atoi(argv[1]);

   mpz_init(tmp1);
   mpz_init(tmp2);

   mpz_init_set_ui(acc, 0);
   mpz_init_set_ui(den, 1);
   mpz_init_set_ui(num, 1);

   for (i = k = 0; i < n;) {
      next_term(++k);
      if (mpz_cmp(num, acc) > 0)
         continue;

      d = extract_digit(3);
      if (d != extract_digit(4))
         continue;

      putchar('0' + d);
      if (++i % 10 == 0)
         printf("\t:%u\n", i);
      eliminate_digit(d);
   }

   return 0;
}
bash-3.2$ gcc -pipe -Wall -O3 -fomit-frame-pointer -march=native  main.c -o pidigits.gcc_run -lgmp
gcc -pipe -Wall -O3 -fomit-frame-pointer -march=native  main.c -o pidigits.gcc_run -lgmp
bash-3.2$ time ./pidigits.gcc_run 10000 > /dev/null
time ./pidigits.gcc_run 10000 > /dev/null

real	0m2.508s
user	0m2.496s
sys	0m0.006s

GCC 6

bash-3.2$ /usr/local/Cellar/gcc/6.1.0/bin/gcc-6 -pipe -Wall -O3 -fomit-frame-pointer -march=native  main.c -o pidigits.gcc_6 -lgmp
bash-3.2$ /usr/local/Cellar/gcc/6.1.0/bin/gcc-6 --version
gcc-6 (Homebrew gcc 6.1.0) 6.1.0
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

bash-3.2$ time ./pidigits.gcc_6 10000 > /dev/null

real	0m2.549s
user	0m2.535s
sys	0m0.007s

GHC 7.10.3

bash-3.2$ cat > Main.hs
-- The Computer Language Benchmarks Game
-- http://benchmarksgame.alioth.debian.org/
-- contributed by Bryan O'Sullivan
-- modified by Eugene Kirpichov: pidgits only generates
-- the result string instead of printing it. For some
-- reason, this gives a speedup.

import System.Environment

pidgits n = 0 % (0 # (1,0,1)) where
 i%ds
  | i >= n = []
  | True = (concat h ++ "\t:" ++ show j ++ "\n") ++ j%t
  where k = i+10; j = min n k
        (h,t) | k > n = (take (n`mod`10) ds ++ replicate (k-n) " ",[])
              | True = splitAt 10 ds
 j # s | n>a || r+n>=d = k # t
     | True = show q : k # (n*10,(a-(q*d))*10,d)
  where k = j+1; t@(n,a,d)=k&s; (q,r)=(n*3+a)`divMod`d
 j&(n,a,d) = (n*j,(a+n*2)*y,d*y) where y=(j*2+1)

main = putStr.pidgits.read.head =<< getArgs
-- The Computer Language Benchmarks Game
-- http://benchmarksgame.alioth.debian.org/
-- contributed by Bryan O'Sullivan
-- modified by Eugene Kirpichov: pidgits only generates
-- the result string instead of printing it. For some
-- reason, this gives a speedup.

import System.Environment

pidgits n = 0 % (0 # (1,0,1)) where
 i%ds
  | i >= n = []
  | True = (concat h ++ "\t:" ++ show j ++ "\n") ++ j%t
  where k = i+10; j = min n k
        (h,t) | k > n = (take (n`mod`10) ds ++ replicate (k-n) " ",[])
              | True = splitAt 10 ds
 j # s | n>a || r+n>=d = k # t
     | True = show q : k # (n*10,(a-(q*d))*10,d)
  where k = j+1; t@(n,a,d)=k&s; (q,r)=(n*3+a)`divMod`d
 j&(n,a,d) = (n*j,(a+n*2)*y,d*y) where y=(j*2+1)

main = putStr.pidgits.read.head =<< getArgs
bash-3.2$ stack ghc -- -O2 Main.hs -o pidigits.haskell
[1 of 1] Compiling Main             ( Main.hs, Main.o )
Linking pidigits.haskell ...
bash-3.2$ time ./pidigits.haskell 10000 > /dev/null

real	0m1.129s
user	0m1.101s
sys	0m0.026s
bash-3.2$ 
bash-3.2$ stack ghc -- --version
The Glorious Glasgow Haskell Compilation System, version 7.10.3

GHC 8.0.1

bash-3.2$ stack ghc -- --version
The Glorious Glasgow Haskell Compilation System, version 8.0.1
bash-3.2$ touch Main.hs; stack ghc -- -O2 Main.hs -o pidigits.haskell
[1 of 1] Compiling Main             ( Main.hs, Main.o )
Linking pidigits.haskell ...
bash-3.2$ time ./pidigits.haskell 10000 > /dev/null

real	0m1.155s
user	0m1.095s
sys	0m0.034s