From: Jason Merrill <jason@redhat.com>
Date: Fri, 2 Apr 2021 18:49:15 +0000 (-0400)
Subject: c++: dependent attribute on parameter [PR97900]
X-Git-Tag: basepoints/gcc-12~292
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23be03a0f243a084a0fe03d0b96a3d045e1a2b65;p=thirdparty%2Fgcc.git

c++: dependent attribute on parameter [PR97900]

We were copying attributes from the template to the instantiation without
considering that they might be dependent.  To make sure that the new parms
have the appropriate properties for the code pattern, let's just regenerate
them.

gcc/cp/ChangeLog:

	PR c++/97900
	* pt.c (regenerate_decl_from_template): tsubst_decl
	the parms.

gcc/testsuite/ChangeLog:

	PR c++/97900
	* g++.dg/ext/vector40.C: New test.
---

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 524a16ab0c66..68ee71397d0f 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -25364,8 +25364,6 @@ regenerate_decl_from_template (tree decl, tree tmpl, tree args)
 
   if (TREE_CODE (decl) == FUNCTION_DECL)
     {
-      tree decl_parm;
-      tree pattern_parm;
       tree specs;
       int args_depth;
       int parms_depth;
@@ -25389,65 +25387,18 @@ regenerate_decl_from_template (tree decl, tree tmpl, tree args)
 	  }
 
       /* Merge parameter declarations.  */
-      decl_parm = skip_artificial_parms_for (decl,
-					     DECL_ARGUMENTS (decl));
-      pattern_parm
-	= skip_artificial_parms_for (code_pattern,
-				     DECL_ARGUMENTS (code_pattern));
-      while (decl_parm && !DECL_PACK_P (pattern_parm))
-	{
-	  tree parm_type;
-	  tree attributes;
-
-	  if (DECL_NAME (decl_parm) != DECL_NAME (pattern_parm))
-	    DECL_NAME (decl_parm) = DECL_NAME (pattern_parm);
-	  parm_type = tsubst (TREE_TYPE (pattern_parm), args, tf_error,
-			      NULL_TREE);
-	  parm_type = type_decays_to (parm_type);
-	  if (!same_type_p (TREE_TYPE (decl_parm), parm_type))
-	    TREE_TYPE (decl_parm) = parm_type;
-	  attributes = DECL_ATTRIBUTES (pattern_parm);
-	  if (DECL_ATTRIBUTES (decl_parm) != attributes)
-	    {
-	      DECL_ATTRIBUTES (decl_parm) = attributes;
-	      cplus_decl_attributes (&decl_parm, attributes, /*flags=*/0);
-	    }
-	  decl_parm = DECL_CHAIN (decl_parm);
-	  pattern_parm = DECL_CHAIN (pattern_parm);
+      if (tree pattern_parm
+	  = skip_artificial_parms_for (code_pattern,
+				       DECL_ARGUMENTS (code_pattern)))
+	{
+	  tree *p = &DECL_ARGUMENTS (decl);
+	  for (int skip = num_artificial_parms_for (decl); skip; --skip)
+	    p = &DECL_CHAIN (*p);
+	  *p = tsubst_decl (pattern_parm, args, tf_error);
+	  for (tree t = *p; t; t = DECL_CHAIN (t))
+	    DECL_CONTEXT (t) = decl;
 	}
-      /* Merge any parameters that match with the function parameter
-         pack.  */
-      if (pattern_parm && DECL_PACK_P (pattern_parm))
-        {
-          int i, len;
-          tree expanded_types;
-          /* Expand the TYPE_PACK_EXPANSION that provides the types for
-             the parameters in this function parameter pack.  */
-          expanded_types = tsubst_pack_expansion (TREE_TYPE (pattern_parm), 
-                                                 args, tf_error, NULL_TREE);
-          len = TREE_VEC_LENGTH (expanded_types);
-          for (i = 0; i < len; i++)
-            {
-              tree parm_type;
-              tree attributes;
-
-              if (DECL_NAME (decl_parm) != DECL_NAME (pattern_parm))
-                /* Rename the parameter to include the index.  */
-                DECL_NAME (decl_parm) = 
-                  make_ith_pack_parameter_name (DECL_NAME (pattern_parm), i);
-              parm_type = TREE_VEC_ELT (expanded_types, i);
-              parm_type = type_decays_to (parm_type);
-              if (!same_type_p (TREE_TYPE (decl_parm), parm_type))
-                TREE_TYPE (decl_parm) = parm_type;
-              attributes = DECL_ATTRIBUTES (pattern_parm);
-              if (DECL_ATTRIBUTES (decl_parm) != attributes)
-                {
-                  DECL_ATTRIBUTES (decl_parm) = attributes;
-                  cplus_decl_attributes (&decl_parm, attributes, /*flags=*/0);
-                }
-              decl_parm = DECL_CHAIN (decl_parm);
-            }
-        }
+
       /* Merge additional specifiers from the CODE_PATTERN.  */
       if (DECL_DECLARED_INLINE_P (code_pattern)
 	  && !DECL_DECLARED_INLINE_P (decl))
diff --git a/gcc/testsuite/g++.dg/ext/vector40.C b/gcc/testsuite/g++.dg/ext/vector40.C
new file mode 100644
index 000000000000..885afb058a53
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/vector40.C
@@ -0,0 +1,10 @@
+// PR c++/97900
+
+template<typename T>
+T test(T __attribute__((vector_size(2 * sizeof(T)))) vec) {
+    return vec[0] + vec[1];
+}
+typedef int v2si __attribute__((vector_size(2 * sizeof(int))));
+int run(v2si vec) {
+    return test<int>(vec);
+}