On 07/23/2011 12:01 AM, Sebastian Pop wrote:
The CLAST produced by CLooG-ISL contains an assignment and GCC chokes
on it. The exact CLAST contains an assignment followed by an if:
scat_1 = max(0,ceild(T_4-7,8));
if (scat_1<= min(1,floord(T_4-1,8))) {
S7(scat_1);
}
This is equivalent to a loop that iterates only once, and so CLooG
generates an assignment followed by an if instead of a loop. This is
an important optimization that was improved in ISL, that allows
if-conversion: imagine GCC having to figure out that a loop like the
following actually iterates only once, and can be converted to an if:
for (scat_1 = max(0,ceild(T_4-7,8)); scat_1<= min(1,floord(T_4-1,8)); scat_1++)
S7(scat_1);
This patch implements the translation of CLAST assignments.
Bootstrapped and tested on amd64-linux.
Hi Sebastian,
thanks for adding this to graphite. One comment inline.
Sebastian
2011-07-22 Sebastian Pop<sebastian....@amd.com>
PR middle-end/48648
* graphite-clast-to-gimple.c (clast_get_body_of_loop): Handle
CLAST assignments.
(translate_clast): Same.
(translate_clast_assignment): New.
* gcc.dg/graphite/id-pr48648.c: New.
---
gcc/ChangeLog | 8 ++++
gcc/graphite-clast-to-gimple.c | 49 ++++++++++++++++++++++++++++
gcc/testsuite/ChangeLog | 5 +++
gcc/testsuite/gcc.dg/graphite/id-pr48648.c | 21 ++++++++++++
4 files changed, 83 insertions(+), 0 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/graphite/id-pr48648.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9cfa21b..303c9c9 100644
+/* Translates a clast assignment STMT to gimple.
+
+ - NEXT_E is the edge where new generated code should be attached.
+ - BB_PBB_MAPPING is is a basic_block and it's related poly_bb_p mapping. */
+
+static edge
+translate_clast_assignment (struct clast_assignment *stmt, edge next_e,
+ int level, ivs_params_p ip)
+{
+ gimple_seq stmts;
+ mpz_t v1, v2;
+ tree type, new_name, var;
+ edge res = single_succ_edge (split_edge (next_e));
+ struct clast_expr *expr = (struct clast_expr *) stmt->RHS;
+ struct clast_user_stmt *body
+ = clast_get_body_of_loop ((struct clast_stmt *) stmt);
I am not a big fan of using clast_get_body_of_loop as it is buggy.
Introducing new uses of it, is nothing what I would support. Do we
really need this?
+ poly_bb_p pbb = (poly_bb_p) cloog_statement_usr (body->statement);
+
+ mpz_init (v1);
+ mpz_init (v2);
What about some more meaningful names like bound_one, bound_two?
+ type = type_for_clast_expr (expr, ip, v1, v2);
+ var = create_tmp_var (type, "graphite_var");
+ new_name = force_gimple_operand (clast_to_gcc_expression (type, expr, ip),
+ &stmts, true, var);
+ add_referenced_var (var);
+ if (stmts)
+ {
+ gsi_insert_seq_on_edge (next_e, stmts);
+ gsi_commit_edge_inserts ();
+ }
+
+ compute_bounds_for_level (pbb, level, v1, v2);
Mh. I do not completely understand all the code. But can't we get v1 and
v2 set without the need for the compute_bounds_for_level function. Is
the type_for_clast_expression not setting them.
Cheers
Tobi
