Expression evaluation errors caused by CSE
I have tested Windows and Linux for this problem, and it will only appear if the target is Linux and -O2 or -O3 is turned on.
I tried adding a custom switch -OoNOCSE disables the CSE and the problem disappears, so it must be a problem caused by optimizing compile
[project1.zip](/uploads/f1d66f70b348b6b22a008f38146dc6bd/project1.zip)
```
program Project1;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}
cthreads,
{$ENDIF}
SysUtils;
function TryEncodeDate(Year, Month, Day: Word; out Date: TDateTime): Boolean;
var
I: Integer;
DayTable: PDayTable;
begin
Result := False;
DayTable := @MonthDays[IsLeapYear(Year)];
if (Year >= 1) and (Year <= 9999) and (Month >= 1) and (Month <= 12) and
(Day >= 1) and (Day <= DayTable^[Month]) then
begin
for I := 1 to Month - 1 do Inc(Day, DayTable^[I]);
I := Year - 1;
// I * 365 + I div 4 - I div 100 + I div 400 + Day - DateDelta;
// = 2024 * 365 + 2024 div 4 - 2024 div 100 + 2024 div 400 + 244 - 693594
// = 738760 + 506 - 20 + 5 + 244 - 693594
// = 45901
// 45901 is correct, but get 45900
Date := I * 365 + I div 4 - I div 100 + I div 400 + Day - DateDelta;
Writeln(' It should output here: 4.5901000000000000E+004');
Writeln('But the actual output is:', Date);
Result := True;
end;
end;
var
LDateTime: TDateTime;
begin
TryEncodeDate(2025, 09, 01, LDateTime);
Writeln('TryEncodeDate:', DateTimeToStr(LDateTime));
end.
```
issue