On Sat, Jul 23, 2011 at 1:01 AM, Sebastian Pop <seb...@gmail.com> 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.
Ok if Tobias is fine with it.
Thanks,
Richard.
> 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
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,11 @@
> +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.
> +
> 2011-07-21 Sebastian Pop <sebastian....@amd.com>
>
> PR middle-end/47654
> diff --git a/gcc/graphite-clast-to-gimple.c b/gcc/graphite-clast-to-gimple.c
> index ddf6d3d..a4668d3 100644
> --- a/gcc/graphite-clast-to-gimple.c
> +++ b/gcc/graphite-clast-to-gimple.c
> @@ -812,6 +812,9 @@ clast_get_body_of_loop (struct clast_stmt *stmt)
> if (CLAST_STMT_IS_A (stmt, stmt_block))
> return clast_get_body_of_loop (((struct clast_block *) stmt)->body);
>
> + if (CLAST_STMT_IS_A (stmt, stmt_ass))
> + return clast_get_body_of_loop (stmt->next);
> +
> gcc_unreachable ();
> }
>
> @@ -1121,6 +1124,48 @@ translate_clast_for (loop_p context_loop, struct
> clast_for *stmt, edge next_e,
> return last_e;
> }
>
> +/* 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);
> + poly_bb_p pbb = (poly_bb_p) cloog_statement_usr (body->statement);
> +
> + mpz_init (v1);
> + mpz_init (v2);
> + 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);
> + save_clast_name_index (ip->newivs_index, stmt->LHS,
> + VEC_length (tree, *(ip->newivs)), level, v1, v2);
> + VEC_safe_push (tree, heap, *(ip->newivs), new_name);
> +
> + mpz_clear (v1);
> + mpz_clear (v2);
> +
> + return res;
> +}
> +
> /* Translates a clast guard statement STMT to gimple.
>
> - NEXT_E is the edge where new generated code should be attached.
> @@ -1171,6 +1216,10 @@ translate_clast (loop_p context_loop, struct
> clast_stmt *stmt, edge next_e,
> else if (CLAST_STMT_IS_A (stmt, stmt_block))
> next_e = translate_clast (context_loop, ((struct clast_block *)
> stmt)->body,
> next_e, bb_pbb_mapping, level, ip);
> +
> + else if (CLAST_STMT_IS_A (stmt, stmt_ass))
> + next_e = translate_clast_assignment ((struct clast_assignment *) stmt,
> + next_e, level, ip);
> else
> gcc_unreachable();
>
> diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
> index a63b647..bfdbcfb 100644
> --- a/gcc/testsuite/ChangeLog
> +++ b/gcc/testsuite/ChangeLog
> @@ -1,3 +1,8 @@
> +2011-07-22 Sebastian Pop <sebastian....@amd.com>
> +
> + PR middle-end/48648
> + * gcc.dg/graphite/id-pr48648.c: New.
> +
> 2011-07-21 Sebastian Pop <sebastian....@amd.com>
>
> PR middle-end/47654
> diff --git a/gcc/testsuite/gcc.dg/graphite/id-pr48648.c
> b/gcc/testsuite/gcc.dg/graphite/id-pr48648.c
> new file mode 100644
> index 0000000..ff58ec2
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/graphite/id-pr48648.c
> @@ -0,0 +1,21 @@
> +/* { dg-options "-O -fgraphite-identity" } */
> +
> +void *foo(const void *a);
> +
> +void bug48648()
> +{
> + unsigned char a[2];
> + long b;
> + int i;
> +
> + for(i = 0; i < 2; i++) {
> + if (b <= 0)
> + a[i] = 0;
> + else if (b >= 8)
> + a[i] = 0;
> + else
> + a[i] = 0;
> + b -= 8;
> + }
> + foo(&a);
> +}
> --
> 1.7.4.1
>
>
