ruby-llvm sample

factorial.out

✗ LD_LIBRARY_PATH="`llvm-config --libdir`" bundle exec ruby samples/factorial.rb 1
; ModuleID = 'Factorial'

define i32 @fac(i32 %n) {
entry:
  %test = icmp eq i32 %n, 1
  br i1 %test, label %result, label %recur

recur:                                            ; preds = %entry
  %n-1 = sub i32 %n, 1
  %"fac(n-1)" = call i32 @fac(i32 %n-1)
  %"n*fac(n-1)" = mul i32 %n, %"fac(n-1)"
  br label %result

result:                                           ; preds = %recur, %entry
  %fac = phi i32 [ 1, %entry ], [ %"n*fac(n-1)", %recur ]
  ret i32 %fac
}
Times show factorial execution times in milliseconds. Both for llvm and ruby iterative and recusive algorithms
Num        llvm rec   recursive  iterative  arrar iter.
20         0.02       0.002      0.001      0.003
50         0.031      0.017      0.015      0.009
100        0.022      0.032      0.038      0.026
200        0.022      0.082      0.078      0.101
500        0.026      0.271      0.285      0.255
1000       0.034      0.752      0.719      0.666
2000       0.046      2.264      2.407      2.286
5000       0.094      19.164     24.753     9.305