[PATCH] middle-end/114931 - type_hash_canon and structual equality types

[Richard Biener <rguenther@suse.de>]

TYPE_STRUCTURAL_EQUALITY_P is part of our type system so we have
to make sure to include that into the type unification done via
type_hash_canon.  This requires the flag to be set before querying
the hash which is the biggest part of the patch.

Bootstrapped and tested on x86_64-unknown-linux-gnu for all languages.

As said in the PR this merely makes sure to keep individual types
consistent with themselves.  We still will have a set of types
with TYPE_STRUCTURAL_EQUALITY_P and a set without that might be
otherwise identical.  That could be only avoided with changes in
the frontend.

OK for trunk?

Thanks,
Richard.

	PR middle-end/114931
gcc/
	* tree.cc (type_hash_canon_hash): Hash TYPE_STRUCTURAL_EQUALITY_P.
	(type_cache_hasher::equal): Compare TYPE_STRUCTURAL_EQUALITY_P.
	(build_array_type_1): Set TYPE_STRUCTURAL_EQUALITY_P before
	probing with type_hash_canon.
	(build_function_type): Likewise.
	(build_method_type_directly): Likewise.
	(build_offset_type): Likewise.
	(build_complex_type): Likewise.
	* attribs.cc (build_type_attribute_qual_variant): Likewise.

gcc/c-family/
	* c-common.cc (complete_array_type): Set TYPE_STRUCTURAL_EQUALITY_P
	before probing with type_hash_canon.

gcc/testsuite/
	* gcc.dg/pr114931.c: New testcase.
---
 gcc/attribs.cc                  | 20 +++++-----
 gcc/c-family/c-common.cc        | 11 ++++--
 gcc/testsuite/gcc.dg/pr114931.c | 10 +++++
 gcc/tree.cc                     | 65 +++++++++++++++++++++++----------
 4 files changed, 74 insertions(+), 32 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr114931.c

diff --git a/gcc/attribs.cc b/gcc/attribs.cc
index 12ffc5f170a..3ab0b0fd87a 100644
--- a/gcc/attribs.cc
+++ b/gcc/attribs.cc
@@ -1336,6 +1336,16 @@ build_type_attribute_qual_variant (tree otype, tree attribute, int quals)
       tree dtype = ntype = build_distinct_type_copy (ttype);
 
       TYPE_ATTRIBUTES (ntype) = attribute;
+      /* If the target-dependent attributes make NTYPE different from
+	 its canonical type, we will need to use structural equality
+	 checks for this type.
+
+	 We shouldn't get here for stripping attributes from a type;
+	 the no-attribute type might not need structural comparison.  But
+	 we can if was discarded from type_hash_table.  */
+      if (TYPE_STRUCTURAL_EQUALITY_P (ttype)
+	  || !comp_type_attributes (ntype, ttype))
+	SET_TYPE_STRUCTURAL_EQUALITY (ntype);
 
       hashval_t hash = type_hash_canon_hash (ntype);
       ntype = type_hash_canon (hash, ntype);
@@ -1343,16 +1353,6 @@ build_type_attribute_qual_variant (tree otype, tree attribute, int quals)
       if (ntype != dtype)
 	/* This variant was already in the hash table, don't mess with
 	   TYPE_CANONICAL.  */;
-      else if (TYPE_STRUCTURAL_EQUALITY_P (ttype)
-	       || !comp_type_attributes (ntype, ttype))
-	/* If the target-dependent attributes make NTYPE different from
-	   its canonical type, we will need to use structural equality
-	   checks for this type.
-
-	   We shouldn't get here for stripping attributes from a type;
-	   the no-attribute type might not need structural comparison.  But
-	   we can if was discarded from type_hash_table.  */
-	SET_TYPE_STRUCTURAL_EQUALITY (ntype);
       else if (TYPE_CANONICAL (ntype) == ntype)
 	TYPE_CANONICAL (ntype) = TYPE_CANONICAL (ttype);
 
diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index 01e3d247fc2..032dcb4b41d 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -7115,6 +7115,13 @@ complete_array_type (tree *ptype, tree initial_value, bool do_default)
   TYPE_TYPELESS_STORAGE (main_type) = TYPE_TYPELESS_STORAGE (type);
   layout_type (main_type);
 
+  /* Set TYPE_STRUCTURAL_EQUALITY_P early.  */
+  if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (main_type))
+      || TYPE_STRUCTURAL_EQUALITY_P (TYPE_DOMAIN (main_type)))
+    SET_TYPE_STRUCTURAL_EQUALITY (main_type);
+  else
+    TYPE_CANONICAL (main_type) = main_type;
+
   /* Make sure we have the canonical MAIN_TYPE. */
   hashval_t hashcode = type_hash_canon_hash (main_type);
   main_type = type_hash_canon (hashcode, main_type);
@@ -7122,7 +7129,7 @@ complete_array_type (tree *ptype, tree initial_value, bool do_default)
   /* Fix the canonical type.  */
   if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (main_type))
       || TYPE_STRUCTURAL_EQUALITY_P (TYPE_DOMAIN (main_type)))
-    SET_TYPE_STRUCTURAL_EQUALITY (main_type);
+    gcc_assert (TYPE_STRUCTURAL_EQUALITY_P (main_type));
   else if (TYPE_CANONICAL (TREE_TYPE (main_type)) != TREE_TYPE (main_type)
 	   || (TYPE_CANONICAL (TYPE_DOMAIN (main_type))
 	       != TYPE_DOMAIN (main_type)))
@@ -7130,8 +7137,6 @@ complete_array_type (tree *ptype, tree initial_value, bool do_default)
       = build_array_type (TYPE_CANONICAL (TREE_TYPE (main_type)),
 			  TYPE_CANONICAL (TYPE_DOMAIN (main_type)),
 			  TYPE_TYPELESS_STORAGE (main_type));
-  else
-    TYPE_CANONICAL (main_type) = main_type;
 
   if (quals == 0)
     type = main_type;
diff --git a/gcc/testsuite/gcc.dg/pr114931.c b/gcc/testsuite/gcc.dg/pr114931.c
new file mode 100644
index 00000000000..d690ed70e52
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr114931.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c23" } */
+
+struct Tcl_Obj;
+void(Tcl_FreeInternalRepProc)(struct Tcl_Obj *);
+typedef struct Tcl_Obj {
+} Tcl_Obj;
+struct {
+  void (*tclFreeObj)(Tcl_Obj *);
+} Tcl_InitStubs;
diff --git a/gcc/tree.cc b/gcc/tree.cc
index 780662549fe..6564b002dc1 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -6012,6 +6012,8 @@ type_hash_canon_hash (tree type)
 
   hstate.add_int (TREE_CODE (type));
 
+  hstate.add_flag (TYPE_STRUCTURAL_EQUALITY_P (type));
+
   if (TREE_TYPE (type))
     hstate.add_object (TYPE_HASH (TREE_TYPE (type)));
 
@@ -6109,6 +6111,10 @@ type_cache_hasher::equal (type_hash *a, type_hash *b)
 	  || TYPE_MODE (a->type) != TYPE_MODE (b->type)))
     return false;
 
+  if (TYPE_STRUCTURAL_EQUALITY_P (a->type)
+      != TYPE_STRUCTURAL_EQUALITY_P (b->type))
+    return false;
+
   switch (TREE_CODE (a->type))
     {
     case VOID_TYPE:
@@ -7347,6 +7353,14 @@ build_array_type_1 (tree elt_type, tree index_type, bool typeless_storage,
   TYPE_DOMAIN (t) = index_type;
   TYPE_ADDR_SPACE (t) = TYPE_ADDR_SPACE (elt_type);
   TYPE_TYPELESS_STORAGE (t) = typeless_storage;
+
+  /* Set TYPE_STRUCTURAL_EQUALITY_P.  */
+  if (set_canonical
+      && (TYPE_STRUCTURAL_EQUALITY_P (elt_type)
+	  || (index_type && TYPE_STRUCTURAL_EQUALITY_P (index_type))
+	  || in_lto_p))
+    SET_TYPE_STRUCTURAL_EQUALITY (t);
+
   layout_type (t);
 
   if (shared)
@@ -7363,7 +7377,7 @@ build_array_type_1 (tree elt_type, tree index_type, bool typeless_storage,
       if (TYPE_STRUCTURAL_EQUALITY_P (elt_type)
 	  || (index_type && TYPE_STRUCTURAL_EQUALITY_P (index_type))
 	  || in_lto_p)
-	SET_TYPE_STRUCTURAL_EQUALITY (t);
+	gcc_unreachable ();
       else if (TYPE_CANONICAL (elt_type) != elt_type
 	       || (index_type && TYPE_CANONICAL (index_type) != index_type))
 	TYPE_CANONICAL (t)
@@ -7510,21 +7524,25 @@ build_function_type (tree value_type, tree arg_types,
       TYPE_NO_NAMED_ARGS_STDARG_P (t) = 1;
     }
 
-  /* If we already have such a type, use the old one.  */
-  hashval_t hash = type_hash_canon_hash (t);
-  tree probe_type = t;
-  t = type_hash_canon (hash, t);
-  if (t != probe_type)
-    return t;
-
   /* Set up the canonical type. */
   any_structural_p   = TYPE_STRUCTURAL_EQUALITY_P (value_type);
   any_noncanonical_p = TYPE_CANONICAL (value_type) != value_type;
   canon_argtypes = maybe_canonicalize_argtypes (arg_types,
 						&any_structural_p,
 						&any_noncanonical_p);
+  /* Set TYPE_STRUCTURAL_EQUALITY_P early.  */
   if (any_structural_p)
     SET_TYPE_STRUCTURAL_EQUALITY (t);
+
+  /* If we already have such a type, use the old one.  */
+  hashval_t hash = type_hash_canon_hash (t);
+  tree probe_type = t;
+  t = type_hash_canon (hash, t);
+  if (t != probe_type)
+    return t;
+
+  if (any_structural_p)
+    gcc_assert (TYPE_STRUCTURAL_EQUALITY_P (t));
   else if (any_noncanonical_p)
     TYPE_CANONICAL (t) = build_function_type (TYPE_CANONICAL (value_type),
 					      canon_argtypes);
@@ -7667,13 +7685,6 @@ build_method_type_directly (tree basetype,
   argtypes = tree_cons (NULL_TREE, ptype, argtypes);
   TYPE_ARG_TYPES (t) = argtypes;
 
-  /* If we already have such a type, use the old one.  */
-  hashval_t hash = type_hash_canon_hash (t);
-  tree probe_type = t;
-  t = type_hash_canon (hash, t);
-  if (t != probe_type)
-    return t;
-
   /* Set up the canonical type. */
   any_structural_p
     = (TYPE_STRUCTURAL_EQUALITY_P (basetype)
@@ -7684,8 +7695,20 @@ build_method_type_directly (tree basetype,
   canon_argtypes = maybe_canonicalize_argtypes (TREE_CHAIN (argtypes),
 						&any_structural_p,
 						&any_noncanonical_p);
+
+  /* Set TYPE_STRUCTURAL_EQUALITY_P early.  */
   if (any_structural_p)
     SET_TYPE_STRUCTURAL_EQUALITY (t);
+
+  /* If we already have such a type, use the old one.  */
+  hashval_t hash = type_hash_canon_hash (t);
+  tree probe_type = t;
+  t = type_hash_canon (hash, t);
+  if (t != probe_type)
+    return t;
+
+  if (any_structural_p)
+    gcc_assert (TYPE_STRUCTURAL_EQUALITY_P (t));
   else if (any_noncanonical_p)
     TYPE_CANONICAL (t)
       = build_method_type_directly (TYPE_CANONICAL (basetype),
@@ -7726,6 +7749,9 @@ build_offset_type (tree basetype, tree type)
 
   TYPE_OFFSET_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
   TREE_TYPE (t) = type;
+  if (TYPE_STRUCTURAL_EQUALITY_P (basetype)
+      || TYPE_STRUCTURAL_EQUALITY_P (type))
+    SET_TYPE_STRUCTURAL_EQUALITY (t);
 
   /* If we already have such a type, use the old one.  */
   hashval_t hash = type_hash_canon_hash (t);
@@ -7741,7 +7767,7 @@ build_offset_type (tree basetype, tree type)
     {
       if (TYPE_STRUCTURAL_EQUALITY_P (basetype)
 	  || TYPE_STRUCTURAL_EQUALITY_P (type))
-	SET_TYPE_STRUCTURAL_EQUALITY (t);
+	gcc_unreachable ();
       else if (TYPE_CANONICAL (TYPE_MAIN_VARIANT (basetype)) != basetype
 	       || TYPE_CANONICAL (type) != type)
 	TYPE_CANONICAL (t)
@@ -7770,6 +7796,8 @@ build_complex_type (tree component_type, bool named)
   tree probe = make_node (COMPLEX_TYPE);
 
   TREE_TYPE (probe) = TYPE_MAIN_VARIANT (component_type);
+  if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (probe)))
+    SET_TYPE_STRUCTURAL_EQUALITY (probe);
 
   /* If we already have such a type, use the old one.  */
   hashval_t hash = type_hash_canon_hash (probe);
@@ -7781,11 +7809,10 @@ build_complex_type (tree component_type, bool named)
 	 out the type.  We need to check the canonicalization and
 	 maybe set the name.  */
       gcc_checking_assert (COMPLETE_TYPE_P (t)
-			   && !TYPE_NAME (t)
-			   && TYPE_CANONICAL (t) == t);
+			   && !TYPE_NAME (t));
 
       if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (t)))
-	SET_TYPE_STRUCTURAL_EQUALITY (t);
+	;
       else if (TYPE_CANONICAL (TREE_TYPE (t)) != TREE_TYPE (t))
 	TYPE_CANONICAL (t)
 	  = build_complex_type (TYPE_CANONICAL (TREE_TYPE (t)), named);
-- 
2.35.3