Missed optimization in PRE?

[Richard Guenther]

On Thu, Mar 29, 2012 at 12:10 PM, Bin.Cheng <amker.cheng@gmail.com> wrote:
> On Thu, Mar 29, 2012 at 6:07 PM, Richard Guenther
> <richard.guenther@gmail.com> wrote:
>> On Thu, Mar 29, 2012 at 12:02 PM, Bin.Cheng <amker.cheng@gmail.com> wrote:
>>> Hi,
>>> Following is the tree dump of 094t.pre for a test program.
>>> Question is loads of D.5375_12/D.5375_14 are redundant on path <bb2,
>>> bb7, bb5, bb6>,
>>> but why not lowered into basic block 3, where it is used.
>>>
>>> BTW, seems no tree pass handles this case currently.
>>
>> tree-ssa-sink.c should do this.
>>
> It does not work for me, I will double check and update soon.

Well, "should" as in, it's the place to do it.  And certainly the pass can sink
loads, so this must be a missed optimization.

Richard.

> --
> Best Regards.