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?
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
