Once it is sure that the result will be infinity, stop computation and return
the result. This ensure that the function call duration is bounded. Before that
change on some cases the computation was taking more than a few seconds.
Tested on x86_64-pc-linux-gnu, committed on trunk
2018-05-25 Nicolas Roche <ro...@adacore.com>
gcc/ada/
* libgnat/s-valrea.adb (Scan_Real): Abort computation once it is sure
that the result will be either -infinite or +infinite.--- gcc/ada/libgnat/s-valrea.adb
+++ gcc/ada/libgnat/s-valrea.adb
@@ -342,7 +342,7 @@ package body System.Val_Real is
-- For base 10, use power of ten table, repeatedly if necessary
elsif Scale > 0 then
- while Scale > Maxpow loop
+ while Scale > Maxpow and then Uval'Valid loop
Uval := Uval * Powten (Maxpow);
Scale := Scale - Maxpow;
end loop;
@@ -350,18 +350,21 @@ package body System.Val_Real is
-- Note that we still know that Scale > 0, since the loop
-- above leaves Scale in the range 1 .. Maxpow.
- Uval := Uval * Powten (Scale);
+ if Uval'Valid then
+ Uval := Uval * Powten (Scale);
+ end if;
elsif Scale < 0 then
- while (-Scale) > Maxpow loop
+ while (-Scale) > Maxpow and then Uval'Valid loop
Uval := Uval / Powten (Maxpow);
Scale := Scale + Maxpow;
end loop;
-- Note that we still know that Scale < 0, since the loop
-- above leaves Scale in the range -Maxpow .. -1.
-
- Uval := Uval / Powten (-Scale);
+ if Uval'Valid then
+ Uval := Uval / Powten (-Scale);
+ end if;
end if;
-- Here is where we check for a bad based number
