Displaying 1 result from an estimated 1 matches for "3ccstdio".
2018 Apr 03
1
Ineffective code after loop unrolling with -O3, ok with -Os
...ling" capabilities of
LLVM's opt.
Seems like LLVM generates slower code with -O3 since it wrongly decides to
unroll a simple loop.
With option -Os, no loop unrolling, the output looks well.
Code:
https://godbolt.org/#g:!((g:!((g:!((h:codeEditor,i:(j:1,lang:c%2B%2B,source:'%23include+%3Ccstdio%3E%0A%0Aint+f(void)%0A%7B%0A++int+n+%3D+100%3B%0A++while+(--n)+%7B%0A++++++puts(%22a%22)%3B%0A++%7D%0A++return+0%3B%0A%7D%0A%0Aint+main(void)+%7B%0A++++f()%3B%0A++++return+0%3B%0A%7D'),l:'5
',n:'0',o:'C%2B%2B+source+%231',t:'0')),k:33.61947345592715,l:'4'...