diff options
Diffstat (limited to 'gcc/fortran/resolve.c')
| -rw-r--r-- | gcc/fortran/resolve.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c index e887fb13..1d6ee85 100644 --- a/gcc/fortran/resolve.c +++ b/gcc/fortran/resolve.c @@ -4918,6 +4918,26 @@ gfc_resolve_iterator (gfc_iterator *iter, bool real_ok) || iter->step->ts.type != iter->var->ts.type) gfc_convert_type (iter->step, &iter->var->ts, 2); + if (iter->start->expr_type == EXPR_CONSTANT + && iter->end->expr_type == EXPR_CONSTANT + && iter->step->expr_type == EXPR_CONSTANT) + { + int sgn, cmp; + if (iter->start->ts.type == BT_INTEGER) + { + sgn = mpz_cmp_ui (iter->step->value.integer, 0); + cmp = mpz_cmp (iter->end->value.integer, iter->start->value.integer); + } + else + { + sgn = mpfr_sgn (iter->step->value.real); + cmp = mpfr_cmp (iter->end->value.real, iter->start->value.real); + } + if ((sgn > 0 && cmp < 0) || (sgn < 0 && cmp > 0)) + gfc_warning ("DO loop at %L will be executed zero times", + &iter->step->where); + } + return SUCCESS; } |