On Wed, 10 Oct 2012, Jakub Jelinek wrote:
> Hi!
>
> As the testcase shows, a REAL_CST can appear in MINUS_EXPR as second operand
> (that is not canonicalized to PLUS_EXPR of negated value, unlike integer
> constants (with exception of minimum value)). The following patch handles
> constants there and punts if it isn't SSA_NAME or a constant that can be
> negated.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Err, why? Can't we negate a constant, too? The ICE simply means
we should have used make_temp_ssa_name (TREE_TYPE (rhs), NULL, NULL)
instead of copy_ssa_name.
Ok with a fix that way.
Thanks,
Richard.
> 2012-10-10 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/54877
> * tree-vect-loop.c (vect_is_simple_reduction_1): For MINUS_EXPR,
> check if rhs2 is SSA_NAME, if not and is constant, try to negate
> it, otherwise bail out.
>
> * gcc.dg/torture/pr54877.c: New test.
>
> --- gcc/tree-vect-loop.c.jj 2012-10-05 13:21:22.000000000 +0200
> +++ gcc/tree-vect-loop.c 2012-10-09 20:45:18.559048120 +0200
> @@ -2382,16 +2382,41 @@ vect_is_simple_reduction_1 (loop_vec_inf
> if (orig_code == MINUS_EXPR)
> {
> tree rhs = gimple_assign_rhs2 (def_stmt);
> - tree negrhs = copy_ssa_name (rhs, NULL);
> - gimple negate_stmt = gimple_build_assign_with_ops (NEGATE_EXPR, negrhs,
> - rhs, NULL);
> - gimple_stmt_iterator gsi = gsi_for_stmt (def_stmt);
> - set_vinfo_for_stmt (negate_stmt, new_stmt_vec_info (negate_stmt,
> - loop_info, NULL));
> - gsi_insert_before (&gsi, negate_stmt, GSI_NEW_STMT);
> - gimple_assign_set_rhs2 (def_stmt, negrhs);
> - gimple_assign_set_rhs_code (def_stmt, PLUS_EXPR);
> - update_stmt (def_stmt);
> +
> + if (TREE_CODE (rhs) == SSA_NAME)
> + {
> + tree negrhs = copy_ssa_name (rhs, NULL);
> + gimple negate_stmt
> + = gimple_build_assign_with_ops (NEGATE_EXPR, negrhs, rhs, NULL);
> + gimple_stmt_iterator gsi = gsi_for_stmt (def_stmt);
> + set_vinfo_for_stmt (negate_stmt,
> + new_stmt_vec_info (negate_stmt,
> + loop_info, NULL));
> + gsi_insert_before (&gsi, negate_stmt, GSI_NEW_STMT);
> + gimple_assign_set_rhs2 (def_stmt, negrhs);
> + gimple_assign_set_rhs_code (def_stmt, PLUS_EXPR);
> + update_stmt (def_stmt);
> + orig_code = PLUS_EXPR;
> + }
> + else if (is_gimple_constant (rhs)
> + && !HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (rhs))))
> + {
> + tree negrhs = fold_unary (NEGATE_EXPR, TREE_TYPE (rhs), rhs);
> + if (negrhs && is_gimple_val (negrhs))
> + {
> + gimple_assign_set_rhs2 (def_stmt, negrhs);
> + gimple_assign_set_rhs_code (def_stmt, PLUS_EXPR);
> + update_stmt (def_stmt);
> + orig_code = PLUS_EXPR;
> + }
> + }
> + if (orig_code == MINUS_EXPR)
> + {
> + if (dump_kind_p (MSG_NOTE))
> + report_vect_op (MSG_NOTE, def_stmt,
> + "reduction: unhandled minus expr: ");
> + return NULL;
> + }
> }
>
> /* Reduction is safe. We're dealing with one of the following:
> --- gcc/testsuite/gcc.dg/torture/pr54877.c.jj 2012-10-09 20:50:43.083259039
> +0200
> +++ gcc/testsuite/gcc.dg/torture/pr54877.c 2012-10-09 20:51:40.463941703
> +0200
> @@ -0,0 +1,23 @@
> +/* PR tree-optimization/54877 */
> +/* { dg-do run } */
> +/* { dg-options "-ffast-math" } */
> +
> +extern void abort (void);
> +
> +int
> +foo (void)
> +{
> + double d;
> + int i;
> + for (i = 0, d = 0; i < 64; i++)
> + d--;
> + return (int) d;
> +}
> +
> +int
> +main ()
> +{
> + if (foo () != -64)
> + abort ();
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend
