On Tue, Jul 25, 2017 at 7:45 PM, Marc Glisse <marc.gli...@inria.fr> wrote: > On Tue, 25 Jul 2017, Richard Biener wrote: > >>> I think we need Richard to say what the intent is for the valueization >>> function. It is used both to stop looking at defining stmt if the return >>> is >>> NULL, and to replace/optimize one SSA_NAME with another, but currently it >>> seems hard to prevent looking at the defining statement without >>> preventing >>> from looking at the SSA_NAME at all. >> >> >> Yeah, this semantic overloading is an issue. For gimple_build we have >> nothing >> to "valueize" but we only use it to tell genmatch that it may not look at >> the >> SSA_NAME_DEF_STMT. >> >>> I guess we'll need a fix in genmatch... >> >> >> I'll have a look tomorrow. > > > My impression yesterday was that we could replace the current do_valueize > wrapper by 2 wrappers (without touching the valueize callbacks): > - may_check_def_stmt, which returns a bool corresponding to the current > do_valueize != NULL_TREE > - maybe_valueize, which tries to valueize, but if it gets a NULL_TREE, it > returns its argument unchanged. > > Not very confident about it though.
Note I've been there in the past (twice I think) but always ran into existing
latent issues. So hopefully we've resolved those, I'm testing the following
simplified variant of what I had back in time.
It'll produce
switch (TREE_CODE (op0))
{
case SSA_NAME:
if (gimple *def_stmt = get_def (valueize, op0))
{
if (gassign *def = dyn_cast <gassign *> (def_stmt))
switch (gimple_assign_rhs_code (def))
{
case MINUS_EXPR:
{
tree o20 = gimple_assign_rhs1 (def);
o20 = do_valueize (valueize, o20);
tree o21 = gimple_assign_rhs2 (def);
o21 = do_valueize (valueize, o21);
if (op1 == o21 || (operand_equal_p (op1, o21, 0) &&
types_match (op1, o21)))
{
which also indents less which is nice.
Bootstrap/regtest running on x86_64-unknown-linux-gnu.
Richard.
2017-07-26 Richard Biener <rguent...@suse.de>
* gimple-match-head.c (do_valueize): Return OP if valueize
returns NULL_TREE.
(get_def): New helper to get at the def stmt of a SSA name
if valueize allows.
* genmatch.c (dt_node::gen_kids_1): Use get_def instead of
do_valueize to get at the def stmt.
(dt_operand::gen_gimple_expr): Simplify do_valueize calls.
> --
> Marc Glisse
p3
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