[PATCH] C++: target attribute - local decl

[Martin Liška]

On 3/4/21 4:45 PM, Jason Merrill wrote:
> 
> Sure, I guess you do need to set that flag for the local decls, but that should be all.
> 
> Jason

Doing that also fails :/
This time likely due to how we set RECORD argument of maybe_version_functions function:

gcc/cp/decl.c:    && maybe_version_functions (newdecl, olddecl,
gcc/cp/decl.c-                                (!DECL_FUNCTION_VERSIONED (newdecl)
gcc/cp/decl.c-                                 || !DECL_FUNCTION_VERSIONED (olddecl))))

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 123f06b1f2b..117f1755191 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -8467,6 +8467,10 @@ get_function_version_dispatcher (tree fn)
  {
    tree dispatcher_decl = NULL;
  
+  if (DECL_LOCAL_DECL_P (fn)
+      && DECL_LOCAL_DECL_ALIAS (fn) != NULL_TREE)
+    fn = DECL_LOCAL_DECL_ALIAS (fn);
+
    gcc_assert (TREE_CODE (fn) == FUNCTION_DECL
  	      && DECL_FUNCTION_VERSIONED (fn));
  
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 1742e286d9f..4fa9c2a0dcb 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -1108,6 +1108,17 @@ decls_match (tree newdecl, tree olddecl, bool record_versions /* = true */)
    return types_match;
  }
  
+static void
+maybe_mark_function_versioned (tree decl)
+{
+  if (!DECL_FUNCTION_VERSIONED (decl))
+    {
+      DECL_FUNCTION_VERSIONED (decl) = 1;
+      if (DECL_ASSEMBLER_NAME_SET_P (decl))
+	mangle_decl (decl);
+    }
+}
+
  /* NEWDECL and OLDDECL have identical signatures.  If they are
     different versions adjust them and return true.
     If RECORD is set to true, record function versions.  */
@@ -1118,18 +1129,20 @@ maybe_version_functions (tree newdecl, tree olddecl, bool record)
    if (!targetm.target_option.function_versions (newdecl, olddecl))
      return false;
  
-  if (!DECL_FUNCTION_VERSIONED (olddecl))
+  maybe_mark_function_versioned (olddecl);
+  if (DECL_LOCAL_DECL_P (olddecl)
+      && DECL_LOCAL_DECL_ALIAS (olddecl) != NULL_TREE)
      {
-      DECL_FUNCTION_VERSIONED (olddecl) = 1;
-      if (DECL_ASSEMBLER_NAME_SET_P (olddecl))
-	mangle_decl (olddecl);
+      olddecl = DECL_LOCAL_DECL_ALIAS (olddecl);
+      maybe_mark_function_versioned (olddecl);
      }
  
-  if (!DECL_FUNCTION_VERSIONED (newdecl))
+  maybe_mark_function_versioned (newdecl);
+  if (DECL_LOCAL_DECL_P (newdecl)
+      && DECL_LOCAL_DECL_ALIAS (newdecl) != NULL_TREE)
      {
-      DECL_FUNCTION_VERSIONED (newdecl) = 1;
-      if (DECL_ASSEMBLER_NAME_SET_P (newdecl))
-	mangle_decl (newdecl);
+      newdecl = DECL_LOCAL_DECL_ALIAS (newdecl);
+      maybe_mark_function_versioned (newdecl);
      }
  
    if (record)
diff --git a/gcc/testsuite/g++.target/i386/pr99108.C b/gcc/testsuite/g++.target/i386/pr99108.C
new file mode 100644
index 00000000000..ad9409b8799
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr99108.C
@@ -0,0 +1,18 @@
+/* PR c++/99108 */
+/* { dg-do compile { target c++20 } } */
+/* { dg-require-ifunc "" }  */
+
+struct A {
+  void foo(auto);
+};
+void A::foo(auto)
+{
+  int f(void) __attribute__((target("default")));
+  int f(void) __attribute__((target("arch=atom")));
+  int b = f();
+}
+void bar(void)
+{
+  A c;
+  c.foo(7);
+}