-Wmissing-attributes: check that we avoid duplicates and false positives

The initial patch for PR 81824 fixed various possibilities of
-Wmissing-attributes reporting duplicates and false positives.  The
test that avoided them was a little obscure, though, so this patch
rewrites it into a more self-evident form.

The patch also adds a testcase that already passed, but that
explicitly covers some of the possibilities of reporting duplicates
and false positives that preexisting tests did not cover.


for  gcc/ChangeLog

	PR middle-end/81824
	* attribs.c (decls_mismatched_attributes): Simplify the logic
	that avoids duplicates and false positives.

for  gcc/testsuite/ChangeLog

	PR middle-end/81824
	* g++.dg/Wmissing-attributes-1.C: New.  Some of its fragments
	are from Martin Sebor.

From-SVN: r273563

1 files changed, 10 insertions, 4 deletions

diff --git a/gcc/attribs.c b/gcc/attribs.c
index 8e54016..f4777c6 100644
--- a/gcc/attribs.c
+++ b/gcc/attribs.c
@@ -1931,15 +1931,19 @@ decls_mismatched_attributes (tree tmpl, tree decl, tree attrlist,
 	  if (!has_attribute (tmpls[j], tmpl_attrs[j], blacklist[i]))
 	    continue;
 
+	  bool found = false;
 	  unsigned kmax = 1 + !!decl_attrs[1];
 	  for (unsigned k = 0; k != kmax; ++k)
 	    {
 	      if (has_attribute (decls[k], decl_attrs[k], blacklist[i]))
-		break;
-
-	      if (!k && kmax > 1)
-		continue;
+		{
+		  found = true;
+		  break;
+		}
+	    }
 
+	  if (!found)
+	    {
 	      if (nattrs)
 		pp_string (attrstr, ", ");
 	      pp_begin_quote (attrstr, pp_show_color (global_dc->printer));
@@ -1947,6 +1951,8 @@ decls_mismatched_attributes (tree tmpl, tree decl, tree attrlist,
 	      pp_end_quote (attrstr, pp_show_color (global_dc->printer));
 	      ++nattrs;
 	    }
+
+	  break;
 	}
     }