tree-cfg: Improve gimple switch verification

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.

2020-08-31  Jakub Jelinek  <jakub@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.

diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 2bae2eeddba34a8447bff299584f36f97898424b..2964209ccff629fff767297807a6e58c73e21f5b 100644 (file)
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -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)
        {