------- Comment #3 from ubizjak at gmail dot com 2009-01-26 17:20 -------
Following patch fixes this problem:
--cut here--
Index: calls.c
===================================================================
--- calls.c (revision 143671)
+++ calls.c (working copy)
@@ -992,7 +992,6 @@ initialize_argument_information (int num
&& targetm.calls.split_complex_arg (argtype))
{
tree subtype = TREE_TYPE (argtype);
- arg = save_expr (arg);
args[j].tree_value = build1 (REALPART_EXPR, subtype, arg);
j += inc;
args[j].tree_value = build1 (IMAGPART_EXPR, subtype, arg);
--cut here--
This testcase triggered sibcall_failure in the loop inside expand_call
function. We expanded complex argument during sibcall sequence expansion and
due to sibcall_failure, we throw produced sequence away.
Since the complex argument was wrapped in SAVE_EXPR, we were not able to
correctly expand function argument during second pass. The argument was already
expanded to a temporary, but the initialization of a temporary was discarded...
This worked in gcc-4.2 (it produces the same initial RTL sequence as unpatched
gcc-4.3/gcc-4.4) since no later pass initializes unintialized registers to
zero. This functionality was introduced by dataflow merge and this bug was
_exposed_ by the merge.
Regression test is in progress...
--
ubizjak at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|-foptimize-sibling-calls |[4.3/4.4 Regression] -
|generates wrong code on |foptimize-sibling-calls
|alpha |generates wrong code on
| |alpha
Target Milestone|--- |4.3.4
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38969
