While the compiler can compute numeric literal with arbitrary large
exponents, this may take ages and is most likely a typo. Better emit an
error when we certainly expect it to take long. The chosen threshold
takes about 100s to compute.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* scng.adb (Nlit): Error on big UI_Scale.diff --git a/gcc/ada/scng.adb b/gcc/ada/scng.adb
--- a/gcc/ada/scng.adb
+++ b/gcc/ada/scng.adb
@@ -772,6 +772,15 @@ package body Scng is
if UI_Scale = 0 then
Int_Literal_Value := UI_Num_Value;
+ -- When the exponent is large, computing is expected to take a
+ -- rather unreasonable time. We generate an error so that it
+ -- does not appear that the compiler has gotten stuck. Such a
+ -- large exponent is most likely a typo anyway.
+
+ elsif UI_Scale >= 800_000 then
+ Error_Msg_SC ("exponent too large");
+ Int_Literal_Value := No_Uint;
+
-- Avoid doing possibly expensive calculations in cases like
-- parsing 163E800_000# when semantics will not be done anyway.
-- This is especially useful when parsing garbled input.
