> Robert, can you attach the testcase you've been working with?
One testcase is libstdc++-v3/libsupc++/vec.cc from mainline.
But it compiles without trouble unless you add verification or a walk
over the SSA_NAMEs at the right time.
> 1. We replace all uses of a phi node with something else
> 2. We then call remove_phi_node with false as the last parameter (only
> 3 places in the compiler), which ends up destroying the phi node but
> not releasing the LHS name (since this is what the last parameter says
> whether to do).
That's right. Zdenek recommended that I change one of those places
(the one in tree_merge_blocks that you quoted) to "true", but doing
that causes some other code of his to break. I haven't analyzed why he
needs those things to stay around, but I suspect it's because -- for a
while, anyway -- he needs the DEF_STMT for something that's been
removed.
-- Robert
