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digitalmars.D.bugs - [Issue 1605] New: break in switch with goto breaks in ctfe

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1605

           Summary: break in switch with goto breaks in ctfe
           Product: D
           Version: 1.022
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: lutger.blijdestijn gmail.com


I stumbled upon a case where a break statement in a switch causes the outer
while loop to exit. This happens only when the function is evaluated at compile
time and a goto statement is involved. Forgive me the bad example: 

int Break()
{
    int i = 0;
    while (true)
    {
        switch(i)
        {
            case 0:
            goto LABEL; // comment out this line and all is fine
             LABEL:
                // at compile time, this breaks out of the while loop:
                break;
            default:
                return i;
        }
        i = 1;
    }
    return 0; // unreachable
}

void main()
{
    assert (Break() == 1); // ok
    static assert(Break() == 1); // not ok
}


--
Oct 21 2007
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1605


Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                 CC|                            |clugdbug yahoo.com.au




--- Comment #1 from Don <clugdbug yahoo.com.au>  2009-08-24 04:21:21 PDT ---
Actually this has nothing to do with switch or break. It only requires 'goto'
inside a while loop.
Reduced test case:

int Break()
{
    int i = 0;
    while (true) {   
        goto LABEL;
        LABEL:
        if (i!=0) return i;
        i = 27;
    }
    assert(i==27); // this passes, it did actually execute the loop.
    return 88; // unreachable
}

static assert(Break() == 27);
-----------
It's failing because the test for continuing to execute is wrong.
----
PATCH: interpret.c, Expression *WhileStatement::interpret(InterState *istate)

    if (e == EXP_BREAK_INTERPRET)
        return NULL;
-    if (e != EXP_CONTINUE_INTERPRET)
+    if (e && e != EXP_CONTINUE_INTERPRET)
        return e;
    }

    while (1)
    {
    e = condition->interpret(istate);

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Aug 24 2009
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1605


Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |FIXED




--- Comment #2 from Walter Bright <bugzilla digitalmars.com>  2009-09-03
13:22:55 PDT ---
Fixed dmd 1.047 and 2.032

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Sep 03 2009