[Bug tree-optimization/37664] [4.4 Regression] ice in remove_range_assertions, at tree-vrp.c:5116

[rguenther at suse dot de]

------- Comment #9 from rguenther at suse dot de  2008-10-15 12:15 -------
Subject: Re:  [4.4 Regression] ice in
 remove_range_assertions, at tree-vrp.c:5116

On Wed, 15 Oct 2008, jakub at gcc dot gnu dot org wrote:

> ------- Comment #8 from jakub at gcc dot gnu dot org  2008-10-15 11:59 -------
> Anyway, the ICE is caused by PR37327.  As
> 139890    rguenth   if (TREE_CODE (val) == INTEGER_CST
> 139890    rguenth       && TREE_OVERFLOW (val))
> 139890    rguenth     val = build_int_cst_wide (TREE_TYPE (val),
> 139890    rguenth                             TREE_INT_CST_LOW (val),
> TREE_INT_CST_HIGH (val));
> removes overflow flag from loc->val, any_uint > UINT_MAX comparison folds to
> false, which triggers the:
> tree cond = fold (ASSERT_EXPR_COND (rhs));
> gcc_assert (cond != boolean_false_node);
> assertion in remove_range_assertions.  To fix this, we could either:
> 1) in register_new_assert_for if TREE_OVERFLOW was set on original val try to
>    fold_binary the condition and if it yields false, don't add the assertion
>    candidate at all
> 2) in process_assert_insertions_for don't add anything if the condition folds
>    to false
> 3) remove the folding and assert in remove_range_assertions

4) make fold fold any_overflowed_uint > UINT_MAX to boolean_false_node

which IMHO makes more sense.  We should try getting rid of spurious
overflow flags in the IL, one way is to make them have no effect.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37664