advanced value range propagation for tree-ssa

[Daniel Berlin]

On Sat, Mar 15, 2008 at 3:57 AM, zhouyi zhou <zhouzhouyi@gmail.com> wrote:
> High,
>    Currently gcc can optimize following program by threading a block:
>  int
>  fn(int s, int w) {
>   int i;
>
>   i = 2;
>
>   if (s)
>    i = 1;
>
>   if (s)
>    printf("%d\n", i);
>
>   return 0;
>  }
>
>   While it cannot handle programs of following kind:
>  int
>  fn(int s, int w) {
>   int i;
>
>   i = 2;
>
>   if (s)
>    i = 1;
>
>   if (w)
>    goto out1;
>
>   if (s)
>    printf("%d\n", i);
>
>  out1:
>   return 0;
>  }
>
>  The advanced value range propagation:
>  http://wiki.freebsd.org/ZhouyiZHOU?action=AttachFile&do=get&target=avrp.patch
>
>  nicely handles the above case
>
>       2 (if s)
>     /   \
>    8     3
>     \     |
>      \__ 4----
>         /
>       5(if s)
>     /  \
>    6   10
>
>  The advanced value range propagation
>  1) identify the candidate basic block pairs by
>  recurively matching the dom son and dom parent (in our case block 5 and block 2 are
>  selected)
>  2) identiy the threadable edge pairs:
>  here edge pair 8-4 and 5-6, 3-4 and 5-10 are selected
>  3) thread the edges (duplicate the basic blocks between)
>       2
>     /  \
>    8    3
>    |     \
>    4'-    4''-
>    |      |
>    5'     5''
>   /       |
>   6        10
>
>  The patch is being compiled and bootstraped on i686-linux m-32.
>  and passed most of regression test by make -k check (the not passed tests
>   are caused the wrong configuration of my machine like libgmp and libmpfr)
>
>  The patch is rudimentary and very dirty written currently, I will clean it in the future
>
>  Your review and reply are greatly appreciated.
>  Zhouyi
>  and libmpfr

You didn't svn add tree-avrp.c, so it doesn't appear in the patch :)
>