re PR c++/5748 (g++ dies with optimization)

	PR c++/5748
	* stmt.c (expand_anon_union_decl): Set TREE_USED on the anon union
	decl if any of elements was TREE_USED.

	* g++.dg/opt/anonunion1.C: New test.

From-SVN: r49971

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b4afe04..252af06 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2002-02-22  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c++/5748
+       * stmt.c (expand_anon_union_decl): Set TREE_USED on the anon union
+       decl if any of elements was TREE_USED.
+
 2002-02-22  Alexandre Oliva  <aoliva@redhat.com>
 
        * config/sparc/sol2.h: Don't include sys/mman.h.

diff --git a/gcc/stmt.c b/gcc/stmt.c
index fc968bc..b41b62b 100644 (file)
--- a/gcc/stmt.c
+++ b/gcc/stmt.c
@@ -4201,6 +4201,11 @@ expand_anon_union_decl (decl, cleanup, decl_elts)
       tree cleanup_elt = TREE_PURPOSE (t);
       enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
 
+      /* If any of the elements are addressable, so is the entire
+        union.  */
+      if (TREE_USED (decl_elt))
+       TREE_USED (decl) = 1;
+
       /* Propagate the union's alignment to the elements.  */
       DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
       DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6785c53..e7149dd 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2002-02-22  Jakub Jelinek  <jakub@redhat.com>
+
+       * g++.dg/opt/anonunion1.C: New test.
+
 2002-02-22  Nathan Sidwell  <nathan@codesourcery.com>
 
        * g++.dg/template/qualttp19.C: New test.

diff --git a/gcc/testsuite/g++.dg/opt/anonunion1.C b/gcc/testsuite/g++.dg/opt/anonunion1.C
new file mode 100644 (file)
index 0000000..445ebaa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/anonunion1.C
@@ -0,0 +1,25 @@
+// PR c++/5748
+// This testcase ICEd because used flag from the anon union variables
+// was not propagated back to the anon union itself, causing addressof
+// not to be replaced with stack slot.
+// { dg-do compile }
+// { dg-options "-O2" }
+
+struct A {
+  A ();
+  ~A ();
+  int foo ();
+  int bar (void *x, int y);
+};
+
+int A::foo()
+{
+  union {
+    int a;
+    int b;
+  };
+
+  if (bar (&a, sizeof (int)) != 32)
+    return 16;
+  return 0;
+}