Don't use subtarget in builtins.c if it has wrong mode (PR middle-end/45567)

Hi!

subtarget passed to expand_builtin is either target, or NULL (the latter
always at -O+, so non-NULL subtarget it isn't tested very well).
This means it has the same mode as target, thus it is inappropriate to pass
it to expand_expr as target when expanding one of builtin's arguments unless
it has the right mode.  The following patch adds a mode check to
expand_builtin_unop, in other cases when it is known that the mode will
never be correct just removes the subtarget argument.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.5?

2010-09-13  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/45567
	* builtins.c (expand_builtin_interclass_mathfn, expand_builtin_cexpi,
	expand_builtin_powi): Remove subtarget argument, pass NULL_RTX instead.
	(expand_builtin): Adjust caller.
	(expand_builtin_unop): Only use subtarget if it has the right mode.

	* gcc.dg/pr45567.c: New test.


	Jakub

On Mon, Sep 13, 2010 at 11:05 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> subtarget passed to expand_builtin is either target, or NULL (the latter
> always at -O+, so non-NULL subtarget it isn't tested very well).
> This means it has the same mode as target, thus it is inappropriate to pass
> it to expand_expr as target when expanding one of builtin's arguments unless
> it has the right mode.  The following patch adds a mode check to
> expand_builtin_unop, in other cases when it is known that the mode will
> never be correct just removes the subtarget argument.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.5?

Ok.

Thanks,
Richard.

> 2010-09-13  Jakub Jelinek  <jakub@redhat.com>
>
>        PR middle-end/45567
>        * builtins.c (expand_builtin_interclass_mathfn, expand_builtin_cexpi,
>        expand_builtin_powi): Remove subtarget argument, pass NULL_RTX instead.
>        (expand_builtin): Adjust caller.
>        (expand_builtin_unop): Only use subtarget if it has the right mode.
>
>        * gcc.dg/pr45567.c: New test.
>
> --- gcc/builtins.c.jj   2010-09-09 10:17:41.000000000 +0200
> +++ gcc/builtins.c      2010-09-13 11:07:21.000000000 +0200
> @@ -106,9 +106,9 @@ static void expand_errno_check (tree, rt
>  static rtx expand_builtin_mathfn (tree, rtx, rtx);
>  static rtx expand_builtin_mathfn_2 (tree, rtx, rtx);
>  static rtx expand_builtin_mathfn_3 (tree, rtx, rtx);
> -static rtx expand_builtin_interclass_mathfn (tree, rtx, rtx);
> +static rtx expand_builtin_interclass_mathfn (tree, rtx);
>  static rtx expand_builtin_sincos (tree);
> -static rtx expand_builtin_cexpi (tree, rtx, rtx);
> +static rtx expand_builtin_cexpi (tree, rtx);
>  static rtx expand_builtin_int_roundingfn (tree, rtx);
>  static rtx expand_builtin_int_roundingfn_2 (tree, rtx);
>  static rtx expand_builtin_next_arg (void);
> @@ -2338,11 +2338,10 @@ interclass_mathfn_icode (tree arg, tree
>    isnan, etc).
>    Return 0 if a normal call should be emitted rather than expanding the
>    function in-line.  EXP is the expression that is a call to the builtin
> -   function; if convenient, the result should be placed in TARGET.
> -   SUBTARGET may be used as the target for computing one of EXP's operands.  */
> +   function; if convenient, the result should be placed in TARGET.  */
>
>  static rtx
> -expand_builtin_interclass_mathfn (tree exp, rtx target, rtx subtarget)
> +expand_builtin_interclass_mathfn (tree exp, rtx target)
>  {
>   enum insn_code icode = CODE_FOR_nothing;
>   rtx op0;
> @@ -2375,7 +2374,7 @@ expand_builtin_interclass_mathfn (tree e
>         side-effects more the once.  */
>       CALL_EXPR_ARG (exp, 0) = arg = builtin_save_expr (arg);
>
> -      op0 = expand_expr (arg, subtarget, VOIDmode, EXPAND_NORMAL);
> +      op0 = expand_expr (arg, NULL_RTX, VOIDmode, EXPAND_NORMAL);
>
>       if (mode != GET_MODE (op0))
>        op0 = convert_to_mode (mode, op0, 0);
> @@ -2442,11 +2441,10 @@ expand_builtin_sincos (tree exp)
>
>  /* Expand a call to the internal cexpi builtin to the sincos math function.
>    EXP is the expression that is a call to the builtin function; if convenient,
> -   the result should be placed in TARGET.  SUBTARGET may be used as the target
> -   for computing one of EXP's operands.  */
> +   the result should be placed in TARGET.  */
>
>  static rtx
> -expand_builtin_cexpi (tree exp, rtx target, rtx subtarget)
> +expand_builtin_cexpi (tree exp, rtx target)
>  {
>   tree fndecl = get_callee_fndecl (exp);
>   tree arg, type;
> @@ -2469,7 +2467,7 @@ expand_builtin_cexpi (tree exp, rtx targ
>       op1 = gen_reg_rtx (mode);
>       op2 = gen_reg_rtx (mode);
>
> -      op0 = expand_expr (arg, subtarget, VOIDmode, EXPAND_NORMAL);
> +      op0 = expand_expr (arg, NULL_RTX, VOIDmode, EXPAND_NORMAL);
>
>       /* Compute into op1 and op2.  */
>       expand_twoval_unop (sincos_optab, op0, op2, op1, 0);
> @@ -3215,7 +3213,7 @@ expand_builtin_pow (tree exp, rtx target
>    function; if convenient, the result should be placed in TARGET.  */
>
>  static rtx
> -expand_builtin_powi (tree exp, rtx target, rtx subtarget)
> +expand_builtin_powi (tree exp, rtx target)
>  {
>   tree arg0, arg1;
>   rtx op0, op1;
> @@ -3244,7 +3242,7 @@ expand_builtin_powi (tree exp, rtx targe
>              || (optimize_insn_for_speed_p ()
>                  && powi_cost (n) <= POWI_MAX_MULTS)))
>        {
> -         op0 = expand_expr (arg0, subtarget, VOIDmode, EXPAND_NORMAL);
> +         op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);
>          op0 = force_reg (mode, op0);
>          return expand_powi (op0, mode, n);
>        }
> @@ -3258,7 +3256,7 @@ expand_builtin_powi (tree exp, rtx targe
>   if (target == NULL_RTX)
>     target = gen_reg_rtx (mode);
>
> -  op0 = expand_expr (arg0, subtarget, mode, EXPAND_NORMAL);
> +  op0 = expand_expr (arg0, NULL_RTX, mode, EXPAND_NORMAL);
>   if (GET_MODE (op0) != mode)
>     op0 = convert_to_mode (mode, op0, 0);
>   op1 = expand_expr (arg1, NULL_RTX, mode2, EXPAND_NORMAL);
> @@ -5000,7 +4998,10 @@ expand_builtin_unop (enum machine_mode t
>     return NULL_RTX;
>
>   /* Compute the argument.  */
> -  op0 = expand_expr (CALL_EXPR_ARG (exp, 0), subtarget,
> +  op0 = expand_expr (CALL_EXPR_ARG (exp, 0),
> +                    (subtarget
> +                     && (TYPE_MODE (TREE_TYPE (CALL_EXPR_ARG (exp, 0)))
> +                         == GET_MODE (subtarget))) ? subtarget : NULL_RTX,
>                     VOIDmode, EXPAND_NORMAL);
>   /* Compute op, into TARGET if possible.
>      Set TARGET to wherever the result comes back.  */
> @@ -5835,7 +5836,7 @@ expand_builtin (tree exp, rtx target, rt
>     CASE_FLT_FN (BUILT_IN_FINITE):
>     case BUILT_IN_ISFINITE:
>     case BUILT_IN_ISNORMAL:
> -      target = expand_builtin_interclass_mathfn (exp, target, subtarget);
> +      target = expand_builtin_interclass_mathfn (exp, target);
>       if (target)
>        return target;
>       break;
> @@ -5865,7 +5866,7 @@ expand_builtin (tree exp, rtx target, rt
>       break;
>
>     CASE_FLT_FN (BUILT_IN_POWI):
> -      target = expand_builtin_powi (exp, target, subtarget);
> +      target = expand_builtin_powi (exp, target);
>       if (target)
>        return target;
>       break;
> @@ -5887,7 +5888,7 @@ expand_builtin (tree exp, rtx target, rt
>       break;
>
>     CASE_FLT_FN (BUILT_IN_CEXPI):
> -      target = expand_builtin_cexpi (exp, target, subtarget);
> +      target = expand_builtin_cexpi (exp, target);
>       gcc_assert (target);
>       return target;
>
> --- gcc/testsuite/gcc.dg/pr45567.c.jj   2010-09-13 11:12:29.000000000 +0200
> +++ gcc/testsuite/gcc.dg/pr45567.c      2010-09-13 11:12:13.000000000 +0200
> @@ -0,0 +1,9 @@
> +/* PR middle-end/45567 */
> +/* { dg-do compile } */
> +/* { dg-options "-ftree-ter" } */
> +
> +unsigned
> +foo (char c)
> +{
> +  return __builtin_popcountl ((unsigned long) c);
> +}
>
>        Jakub
>