In working on tile I noticed an unnecessary modulo operation for the calculation
of the outermost loop's user iteration variable. By construction the modulo
operator is useless here. Took the opportunity of moving the modulo and
division operations next to eachother so it'd be easier to make use of any
divmod apparatus the target may have.
committed to gomp4.
nathan
2016-09-30 Nathan Sidwell <nat...@codesourcery.com>
* omp-low.c (expand_oacc_collapse_vars): Avoid DIV for outermost
collaps var.
Index: omp-low.c
===================================================================
--- omp-low.c (revision 240653)
+++ omp-low.c (working copy)
@@ -7591,8 +7591,16 @@ expand_oacc_collapse_vars (const struct
plus_type = sizetype;
}
- expr = fold_build2 (TRUNC_MOD_EXPR, ivar_type, ivar,
- fold_convert (ivar_type, collapse->iters));
+ expr = ivar;
+ if (ix)
+ {
+ tree mod = fold_convert (ivar_type, collapse->iters);
+ ivar = fold_build2 (TRUNC_DIV_EXPR, ivar_type, expr, mod);
+ expr = fold_build2 (TRUNC_MOD_EXPR, ivar_type, expr, mod);
+ ivar = force_gimple_operand_gsi (gsi, ivar, true, NULL_TREE,
+ true, GSI_SAME_STMT);
+ }
+
expr = fold_build2 (MULT_EXPR, diff_type, fold_convert (diff_type, expr),
collapse->step);
expr = fold_build2 (plus_code, iter_type, collapse->base,
@@ -7601,14 +7609,6 @@ expand_oacc_collapse_vars (const struct
true, GSI_SAME_STMT);
gassign *ass = gimple_build_assign (loop->v, expr);
gsi_insert_before (gsi, ass, GSI_SAME_STMT);
-
- if (ix)
- {
- expr = fold_build2 (TRUNC_DIV_EXPR, ivar_type, ivar,
- fold_convert (ivar_type, collapse->iters));
- ivar = force_gimple_operand_gsi (gsi, expr, true, NULL_TREE,
- true, GSI_SAME_STMT);
- }
}
}
