On Tue, Jul 25, 2017 at 7:45 PM, Marc Glisse <marc.glisse@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 <rguenther@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
2017-07-26 Richard Biener <rguenther@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.
Index: gcc/gimple-match-head.c
===================================================================
--- gcc/gimple-match-head.c (revision 250518)
+++ gcc/gimple-match-head.c (working copy)
@@ -779,10 +779,25 @@ inline tree
do_valueize (tree (*valueize)(tree), tree op)
{
if (valueize && TREE_CODE (op) == SSA_NAME)
- return valueize (op);
+ {
+ tree tem = valueize (op);
+ if (tem)
+ return tem;
+ }
return op;
}
+/* Helper for the autogenerated code, get at the definition of NAME when
+ VALUEIZE allows that. */
+
+inline gimple *
+get_def (tree (*valueize)(tree), tree name)
+{
+ if (valueize && ! valueize (name))
+ return NULL;
+ return SSA_NAME_DEF_STMT (name);
+}