[Issue 13169] New: Optimization - final switch need not check for default case

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13169

          Issue ID: 13169
           Summary: Optimization - final switch need not check for default
                    case
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: DMD
          Assignee: nobody at puremagic.com
          Reporter: bugzilla at digitalmars.com

void A();
void B();
void C();
void D();
void E();

void test(int i)
{
    while (1)
    {
        final switch (i)
        {
            case 1: A(); break;
            case 2: B(); break;
            case 3: C(); break;
            case 4: D(); break;
            case 5: E(); break;
        }
        ++i;
    }
}

An overflow check is done before dispatch, even with -O -release
-noboundscheck.

See also:

http://eli.thegreenplace.net/2012/07/12/computed-goto-for-efficient-dispatch-tables/

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