Fix for IA-64 union/long double ICE.

PR target/16364
* config/ia64/ia64.c (ia64_function_arg): For a single element HFA,
do return a parallel if hfa_mode == XFmode and mode == TImode.
* gcc.c-torture/compile/20040709-1.c: New.

From-SVN: r84416

gcc/ChangeLog

+2004-07-09  James E Wilson  <wilson@specifixinc.com>
+
+	PR target/16364
+	* config/ia64/ia64.c (ia64_function_arg): For a single element HFA,
+	do return a parallel if hfa_mode == XFmode and mode == TImode.
+
 2004-07-09 Jan Beulich <jbeulich@novell.com>
 
 	* builtin-types.def (BT_UINT): Rename from BT_UNSIGNED.

gcc/config/ia64/ia64.c

@@ -3746,8 +3746,12 @@ ia64_function_arg (CUMULATIVE_ARGS *cum, enum machine_mode mode, tree type,
 	}
 
       /* If we ended up using just one location, just return that one loc, but
-	 change the mode back to the argument mode.  */
-      if (i == 1)
+	 change the mode back to the argument mode.  However, we can't do this
+	 when hfa_mode is XFmode and mode is TImode.  In that case, we would
+	 return a TImode reference to an FP reg, but FP regs can't hold TImode.
+	 We need the PARALLEL to make this work.  This can happen for a union
+	 containing a single __float80 member.  */
+      if (i == 1 && ! (hfa_mode == XFmode && mode == TImode))
 	return gen_rtx_REG (mode, REGNO (XEXP (loc[0], 0)));
       else
 	return gen_rtx_PARALLEL (mode, gen_rtvec_v (i, loc));

gcc/testsuite/ChangeLog

+2004-07-09  James E Wilson  <wilson@specifixinc.com>
+
+	PR target/16364
+	* gcc.c-torture/compile/20040709-1.c: New.
+
 2004-07-09  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
 	
 	PR fortran/14077

gcc/testsuite/gcc.c-torture/compile/20040709-1.c

+/* PR target/16364 */
+union foo {
+  long double ld;
+} bar;
+
+double
+sub (union foo baz)
+{
+  return baz.ld / 2;
+}