[PATCH] Use the middle-end boolean_type_node

[Dominik Vogt]

On Tue, Dec 13, 2016 at 10:59:09PM +0200, Janne Blomqvist wrote:
> Use the boolean_type_node setup by the middle-end instead of
> redefining it. boolean_type_node is not used in GFortran for any
> ABI-visible stuff, only internally as the type of boolean
> expressions. There appears to be one exception to this, namely the
> caf_get* and caf_send* calls which have boolean_type_node
> arguments. However, on the library side they seem to use C _Bool, so I
> suspect this might be a case of a argument mismatch that hasn't
> affected anything so far.
> 
> The practical effect of this is that the size of such variables will
> be the same as a C _Bool or C++ bool, that is, on most targets a
> single byte. Previously we redefined boolean_type_node to be a Fortran
> default logical kind sized variable, that is 4 or 8 bytes depending on
> compile options. This might enable slightly more compact code, in case
> the optimizer determines that the result of such a generated
> comparison expression needs to be stored in some temporary location
> rather than being used immediately.

This patch costs several thousand additional instructions in
Spec2006 on s390x ("lines" = instructions):

  410.bwaves:     +28 lines (2 funcs bigger)
  437.leslie3d:   +43 lines (5 funcs bigger)
  434.zeusmp:   +2650 lines (15 funcs bigger)
  459.GemsFDTD:   +65 lines (7 funcs bigger)
  454.calculix:  +474 lines (23 funcs bigger)
  465.tonto:    +2182 lines (221 funcs bigger)
  481.wrf:      +4988 lines (117 funcs bigger)
  416.gamess:   +3723 lines (466 funcs bigger)

s390x has a "compare with immediate and jump relative" instruction
for 32 bit, but for an 8 bit quantities it needs separate compare
and jump instructions, e.g.

  cijne   %r1,0,... <bi_cgstab_block_+0xfe2>

->

  tmll    %r1,1
  jne     ... <bi_cgstab_block_+0xfe6>

Instead of hard coding a specific type, should one ask the backend
for the preferred type?

> Regression tested on x86_64-pc-linux-gnu, Ok for trunk?
> 
> 2016-12-13  Janne Blomqvist  <jb@gcc.gnu.org>
> 
> 	* trans-types.c (gfc_init_types): Don't redefine boolean type node.
> ---
>  gcc/fortran/trans-types.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/gcc/fortran/trans-types.c b/gcc/fortran/trans-types.c
> index 354308f..e8dafa0 100644
> --- a/gcc/fortran/trans-types.c
> +++ b/gcc/fortran/trans-types.c
> @@ -961,10 +961,6 @@ gfc_init_types (void)
>  			wi::mask (n, UNSIGNED,
>  				  TYPE_PRECISION (size_type_node)));
>  
> -  boolean_type_node = gfc_get_logical_type (gfc_default_logical_kind);
> -  boolean_true_node = build_int_cst (boolean_type_node, 1);
> -  boolean_false_node = build_int_cst (boolean_type_node, 0);
> -
>    /* ??? Shouldn't this be based on gfc_index_integer_kind or so?  */
>    gfc_charlen_int_kind = 4;
>    gfc_charlen_type_node = gfc_get_int_type (gfc_charlen_int_kind);
> -- 
> 2.7.4


Ciao

Dominik ^_^  ^_^

-- 

Dominik Vogt
IBM Germany