[tree-ssa] USE or VUSE bugs?

[Daniel Berlin]

On Sunday, April 27, 2003, at 11:41  PM, Wei Liu wrote:

>
> On Sun, 27 Apr 2003, Daniel Berlin wrote:
>
>>
>> On Sunday, April 27, 2003, at 10:59  PM, Wei Liu wrote:
>>
>>> I have a very simple kernel as follows. The problem is, for statement
>>> a=b+c, there is no USE or VUSE I can get from get_ops and get_vops.
>> At what point?
>> IE Where is your code inserted that you are seeing this.
>>
>
> My code is inserted in tree-optimize.c and just after tree_ssa_dce 
> pass. I
> hope I can operands b and c, but what I got is only .GLOBAL_VAR_20.
Sorry, should have looked closer at your code.
This is because b and c are call clobbered, so they aren't renamed.
Thus, the SSA optimizers aren't supposed to touch them (since they 
aren't in SSA form), and to make this so, they don't appear in the 
use_ops.
a is a global, so it isn't renamed either.