4e896dad49
This gets rid of redundant range checks generated in 5 out of the 9
cases of scalar conversions, i.e. (integer, fixed-point, floating-point)
converted to (integer, fixed-point, floating-point).
The problem is that the Real_Range_Check routine rewrites the conversion
node into a conversion to the base type so, when its parent node is
analyzed, a new conversion to the subtype may be introduced, depending
on the context, giving rise to a second range check against the subtype
bounds.
This change makes Real_Range_Check rewrite the expression of the
conversion node instead of the node, so that the type of the node is
preserved and no new conversion is introduced. As a matter of fact,
this is exactly what happens in the float-to-float case which goes to
the Generate_Range_Check circuit instead and does not suffer from the
duplication of range checks.
For the following procedure, the compiler must now generate exactly one
range check per nested function:
procedure P is
type I1 is new Integer range -100 .. 100;
type I2 is new Integer range -200 .. 200;
type D1 is delta 0.5 range -100.0 .. 100.0;
type D2 is delta 0.5 range -200.0 .. 200.0;
type F1 is new Long_Float range -100.0 .. 100.0;
type F2 is new Long_Float range -200.0 .. 200.0;
function Conv (A : I2) return I1 is
begin
return I1 (A);
end;
function Conv (A : D2) return I1 is
begin
return I1 (A);
end;
function Conv (A : F2) return I1 is
begin
return I1 (A);
end;
function Conv (A : I2) return D1 is
begin
return D1 (A);
end;
function Conv (A : D2) return D1 is
begin
return D1 (A);
end;
function Conv (A : F2) return D1 is
begin
return D1 (A);
end;
function Conv (A : I2) return F1 is
begin
return F1 (A);
end;
function Conv (A : D2) return F1 is
begin
return F1 (A);
end;
function Conv (A : F2) return F1 is
begin
return F1 (A);
end;
begin
null;
end;
2019-08-12 Eric Botcazou <ebotcazou@adacore.com>
gcc/ada/
* exp_ch4.adb (Real_Range_Check): Do not rewrite the conversion
node but its expression instead, after having fetched its
current value. Clear the Do_Range_Check flag on entry. Return
early for a rewritten float-to-float conversion. Remove
redundant local variable. Suppress all checks when inserting
the temporary and do not reanalyze the node.
From-SVN: r274287
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