4 files changed, 44 insertions, 2 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6b987df..fee4680 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2004-12-15  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR c++/17972
+	* tree-inline.c (expand_call_inline): Set TREE_SIDE_EFFECTS
+	on the STMT_EXPR wrapping up the inlined body.
+
 2004-12-15  Vladimir Makarov  <vmakarov@redhat.com>
             Steven Bosscher  <stevenb@suse.de>
 	PR middle end/17340
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 58d4e78..06dd868 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2004-12-15  Alan Modra  <amodra@bigpond.net.au>
+
+	* g++.dg/opt/inline9.C: New test.
+
 2004-12-15  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
 
 	PR fortran/18993
diff --git a/gcc/testsuite/g++.dg/opt/inline9.C b/gcc/testsuite/g++.dg/opt/inline9.C
new file mode 100644
index 0000000..10ccb47
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/inline9.C
@@ -0,0 +1,29 @@
+// PR c++/17972
+// Origin: Michal Ostrowski <mostrows@watson.ibm.com>
+// Testcase by Alan Modra <amodra@bigpond.net.au>
+// { dg-do run }
+// { dg-options "-O" }
+// { dg-options "-O -mtune=i686" { target i?86-*-* } }
+
+struct thread_info
+{
+  short preempt_count;
+} x;
+
+static inline struct thread_info *cti (void) __attribute__ ((const));
+static inline struct thread_info *cti (void)
+{
+  return &x;
+}
+
+void fn (void) __attribute__ ((noinline));
+void fn (void)
+{
+  ++cti()->preempt_count;
+}
+
+int main (void)
+{
+  fn ();
+  return 0;
+}
diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c
index db2b236..61fe66d 100644
--- a/gcc/tree-inline.c
+++ b/gcc/tree-inline.c
@@ -1625,8 +1625,11 @@ expand_call_inline (tree *tp, int *walk_subtrees, void *data)
   splay_tree_delete (id->decl_map);
   id->decl_map = st;
 
-  /* The new expression has side-effects if the old one did.  */
-  TREE_SIDE_EFFECTS (expr) = TREE_SIDE_EFFECTS (t);
+  /* Although, from the semantic viewpoint, the new expression has
+     side-effects only if the old one did, it is not possible, from
+     the technical viewpoint, to evaluate the body of a function
+     multiple times without serious havoc.  */
+  TREE_SIDE_EFFECTS (expr) = 1;
 
   tsi_link_before (&id->tsi, expr, TSI_SAME_STMT);