This patch recognizes additional object declarations whose defining
identifier is known statically to be valid. This allows additional
optimizations to be performed by the front-end.
Executing:
gcc -c -gnatDG p.ads
On the following sources:
----
with G;
With Q;
package P is
Val : constant Positive := Q.Config_Value ("Size");
package My_G is new G (Val);
end P;
----
generic
Num : Natural := 0;
package G is
Multi : constant Boolean := Num > 0;
type Info is array (True .. Multi) of Integer;
type Arr is array (Natural range <>) of Boolean;
type Rec (D : Natural) is record
C : character;
I : Info;
E : Arr (0 .. D);
end record;
end G;
----
package Q is
function Config_Value (S : String) return Integer;
end Q;
----
Must yield (note that variable Multi has been statically optimized to
true):
----
with g;
with q;
p_E : short_integer := 0;
package p is
p__R2s : constant integer := q.q__config_value ("Size");
[constraint_error when
not (p__R2s >= 1)
"range check failed"]
p__val : constant positive := p__R2s;
package p__my_g is
p__my_g__num : constant natural := p__val;
package p__my_g__g renames p__my_g;
package p__my_g__gGH renames p__my_g__g;
p__my_g__multi : constant boolean := true;
type p__my_g__info is array (true .. p__my_g__multi) of integer;
type p__my_g__arr is array (0 .. 16#7FFF_FFFF# range <>) of
boolean;
type p__my_g__rec (d : natural) is record
c : character;
i : p__my_g__info;
e : p__my_g__arr (0 .. d);
end record;
[type p__my_g__TinfoB is array (true .. p__my_g__multi range <>) of
integer]
freeze p__my_g__TinfoB [
procedure p__my_g__TinfoBIP (_init : in out p__my_g__TinfoB) is
begin
null;
return;
end p__my_g__TinfoBIP;
]
freeze p__my_g__info []
freeze p__my_g__arr [
procedure p__my_g__arrIP (_init : in out p__my_g__arr) is
begin
null;
return;
end p__my_g__arrIP;
]
freeze p__my_g__rec [
procedure p__my_g__recIP (_init : in out p__my_g__rec; d :
natural) is
begin
_init.d := d;
null;
return;
end p__my_g__recIP;
]
end p__my_g;
package my_g is new g (p__val);
end p;
freeze_generic info
[subtype TinfoD1 is boolean range true .. multi]
freeze_generic TinfoD1
[type TinfoB is array (true .. multi range <>) of integer]
freeze_generic TinfoB
freeze_generic arr
freeze_generic rec
----
2018-11-14 Ed Schonberg <schonberg@adacore.com>
gcc/ada/
* sem_ch3.adb (Analyze_Object_Declaration): Use the
Actual_Subtype to preserve information about a constant
initialized with a non-static entity that is known to be valid,
when the type of the entity has a narrower range than that of
the nominal subtype of the constant.
* checks.adb (Determine_Range): If the expression is a constant
entity that is known-valid and has a defined Actual_Subtype, use
it to determine the actual bounds of the value, to enable
additional optimizations.
From-SVN: r266123
