From 4eb4ffd7085e84444df44b13615b9a38f3490ac9 Mon Sep 17 00:00:00 2001
From: jakub <jakub@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Tue, 17 May 2005 06:45:49 +0000
Subject: [PATCH] 	PR tree-optimization/21610 	* c-typeck.c
 (decl_constant_value_for_broken_optimization): If not 	returning DECL, call
 unshare_expr.

	* gcc.c-torture/compile/20050516-1.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@99815 138bc75d-0d04-0410-961f-82ee72b054a4
---
 gcc/ChangeLog                                    |  6 ++++++
 gcc/c-typeck.c                                   | 12 ++++++++++--
 gcc/testsuite/ChangeLog                          |  3 +++
 gcc/testsuite/gcc.c-torture/compile/20050516-1.c | 12 ++++++++++++
 4 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.c-torture/compile/20050516-1.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7bab281..99e0108 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2005-05-17  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/21610
+	* c-typeck.c (decl_constant_value_for_broken_optimization): If not
+	returning DECL, call unshare_expr.
+
 2005-05-17  Hans-Peter Nilsson  <hp@axis.com>
 
 	* config/cris/cris.md: Unquote preparation and output statements.
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 806a20a..b96328d 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -1249,10 +1249,18 @@ decl_constant_value (tree decl)
 static tree
 decl_constant_value_for_broken_optimization (tree decl)
 {
+  tree ret;
+
   if (pedantic || DECL_MODE (decl) == BLKmode)
     return decl;
-  else
-    return decl_constant_value (decl);
+
+  ret = decl_constant_value (decl);
+  /* Avoid unwanted tree sharing between the initializer and current
+     function's body where the tree can be modified e.g. by the
+     gimplifier.  */
+  if (ret != decl && TREE_STATIC (decl))
+    ret = unshare_expr (ret);
+  return ret;
 }
 
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2e99a36..e691174 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2005-05-17  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/21610
+	* gcc.c-torture/compile/20050516-1.c: New test.
+
 	PR fortran/15080
 	* gfortran.fortran-torture/execute/forall_3.f90: Remove comment
 	about the test failing.
diff --git a/gcc/testsuite/gcc.c-torture/compile/20050516-1.c b/gcc/testsuite/gcc.c-torture/compile/20050516-1.c
new file mode 100644
index 0000000..2cdf696
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/20050516-1.c
@@ -0,0 +1,12 @@
+/* PR tree-optimization/21610 */
+
+struct S { char s; };
+struct T { struct S t; };
+
+struct S *const p = &((struct T * const) (0x4000))->t;
+
+void
+foo (void)
+{
+  p->s = 0;
+}
-- 
2.7.4