diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3151f57deb0..da17d5f114a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2007-11-18  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/34127
+	* tree-ssa-forwprop.c (tree_ssa_forward_propagate_single_use_vars):
+	Make code match up the comments, require compatibility of the
+	pointed-to types.
+
 2007-11-17  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/34130
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 62d039e27eb..2868de08513 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-11-18  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/34127
+	* gcc.c-torture/compile/pr34127.c: New testcase.
+
 2007-11-18  Ben Elliston  <bje@au.ibm.com>
 
 	* gcc.target/powerpc/altivec-23.c: Do not use a typedef name as a
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr34127.c b/gcc/testsuite/gcc.c-torture/compile/pr34127.c
new file mode 100644
index 00000000000..10d41acaf52
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr34127.c
@@ -0,0 +1,9 @@
+static void 
+whichtable(char **pfmt)
+{
+  --*pfmt;
+}
+void prepare_s(const char *fmt)
+{
+  whichtable((char **)&fmt);
+}
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 661d3d2a240..3e30454ab9f 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -959,8 +959,8 @@ tree_ssa_forward_propagate_single_use_vars (void)
 		       || TREE_CODE (rhs) == CONVERT_EXPR)
 		      && TREE_CODE (TREE_OPERAND (rhs, 0)) == ADDR_EXPR
 		      && POINTER_TYPE_P (TREE_TYPE (rhs))
-		      && useless_type_conversion_p (TREE_TYPE (TREE_TYPE (TREE_OPERAND (rhs, 0))),
-						    TREE_TYPE (TREE_TYPE (rhs)))))
+		      && types_compatible_p (TREE_TYPE (TREE_TYPE (TREE_OPERAND (rhs, 0))),
+					     TREE_TYPE (TREE_TYPE (rhs)))))
 		{
 		  if (forward_propagate_addr_expr (lhs, rhs))
 		    {