On Mon, Aug 31, 2020 at 10:39 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> On Mon, Aug 31, 2020 at 10:33:20AM +0200, Richard Biener wrote:
> > In any case type mismatches here are of course unfortunate
> > and both more verification and documentation would be
> > nice. verify_gimple_switch only verifies all case labels
> > have the same type, the type of the switch argument is
> > not verified in any way against that type.
>
> When looking at the verification, I have noticed a bug in it.
>
> The verification that CASE_HIGH (if present) has the same type as CASE_LOW
> is only performed for the case label 2 and higher, case label 1 (the first
> one after the default label) isn't checked.
>
> The following patch fixes that, it will uselessly also compare
> TREE_TYPE (CASE_LOW (elt)) != elt_type for the case label 1, but I think
> that isn't that expensive and helps readability of the code.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
> 2020-08-31 Jakub Jelinek <ja...@redhat.com>
>
> * tree-cfg.c (verify_gimple_switch): If the first non-default case
> label has CASE_HIGH, verify it has the same type as CASE_LOW.
>
> --- gcc/tree-cfg.c.jj 2020-08-27 18:42:35.660711349 +0200
> +++ gcc/tree-cfg.c 2020-08-27 22:46:34.574154370 +0200
> @@ -4809,17 +4809,7 @@ verify_gimple_switch (gswitch *stmt)
> return true;
> }
>
> - if (elt_type)
> - {
> - if (TREE_TYPE (CASE_LOW (elt)) != elt_type
> - || (CASE_HIGH (elt) && TREE_TYPE (CASE_HIGH (elt)) != elt_type))
> - {
> - error ("type mismatch for case label in switch statement");
> - debug_generic_expr (elt);
> - return true;
> - }
> - }
> - else
> + if (! elt_type)
> {
> elt_type = TREE_TYPE (CASE_LOW (elt));
> if (TYPE_PRECISION (index_type) < TYPE_PRECISION (elt_type))
> @@ -4828,6 +4818,13 @@ verify_gimple_switch (gswitch *stmt)
> return true;
> }
> }
> + if (TREE_TYPE (CASE_LOW (elt)) != elt_type
> + || (CASE_HIGH (elt) && TREE_TYPE (CASE_HIGH (elt)) != elt_type))
> + {
> + error ("type mismatch for case label in switch statement");
> + debug_generic_expr (elt);
> + return true;
> + }
>
> if (prev_upper_bound)
> {
>
>
> Jakub
>
