[Bug tree-optimization/30604] Unable to coalesce ssa_names <x> and <y> which are marked as MUST COALESCE

[Daniel Berlin]

On 8 Mar 2007 20:12:16 -0000, amacleod at redhat dot com
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #7 from amacleod at redhat dot com  2007-03-08 20:12 -------
> Looking at the original testcase, the complaint is that _t_8232 and _t_3 are
> both used in the PHI definition of _t_7.  (using mainline from march 5th)
>
> ie,  _t_7(ab) = PHI <...., _t_8232, ... , _t_3, ...>
>

Uh, did you not put the (ab) next to the arguments, or do they really
not have SSA_NAME_OCCURS_IN_ABNORMAL_PHI set on them? (They should)

> I can't really read the detailed output from FRE, but it does seem to have
> replaced a bunch of expressions with _t_3, so that would appear to be the
> culprit.

It won't value number things with SSA_NAME_OCCURS_IN_ABNORMAL_PHI set,
so it should never eliminate anything with them.