[Bug middle-end/47725] [x32] error: unable to find a register to spill in class DIREG

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47725

--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> 2011-02-14 14:13:32 UTC ---
This seems to work:

diff --git a/gcc/function.c b/gcc/function.c
index 3f721fb..4c78407 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -3000,11 +3000,15 @@ assign_parm_setup_reg (struct assign_parm_data_all
*all,
 tree parm,
       && insn_data[icode].operand[1].predicate (op1, data->passed_mode))
     {
       enum rtx_code code = unsignedp ? ZERO_EXTEND : SIGN_EXTEND;
-      rtx insn, insns;
+      rtx insn, insns, copy;
       HARD_REG_SET hardregs;

       start_sequence ();
-      insn = gen_extend_insn (op0, op1, promoted_nominal_mode,
+      /* We must copy the hard register first before extending it.
+         Otherwise, combine won't see the hard register.  */
+      copy = gen_reg_rtx (data->passed_mode);
+      emit_move_insn (copy, op1);
+      insn = gen_extend_insn (op0, copy, promoted_nominal_mode,
                   data->passed_mode, unsignedp);
       emit_insn (insn);
       insns = get_insns ();