> Of course it shouldn't happen.  But there are lots of reasons it can
> happen, and a bug in the compiler is only one of them.  The original
> poster did not claim the above code actually fails.

Here is the document I kept when I debugged the software. From the revision
history and test results, one can decide if there is a bug in the compiler
8.00PL3.

Background: version 25 code is a released code originally compiled by
7.87PL4. After upgrading to 8.00PL3 we needed to make modifications to the
product. I compiled the modified code with 8.00PL3 and it didn't work. After
a few days of frustrations I suspected compiler problem and decided to test
it with the original code 25. Version 25 didn't work when compiled by
8.00PL3. Then I wrote a series of debugging version 25T{x} to test. Here are
the document. I copied part of the report here and reformatted it for
readability.

================
Code Version: 25
Compiler 7.87PL4: Tests passed
Compiler 8.00PL3: Tests failed

Code Version: 25T6 (This is a stripped down version of 25, only a few
functions and simple features left.)
Compiler 7.87PL4: Tests passed
Compiler 8.00PL3: Tests failed

Code Version: 25T8
Changes made from 25T6: All local variables moved out from functions;
function parameters kept intact
Compiler 8.00PL3: Some tests passed; some failed

Code Version: 25T9
Changes made from 25T6: All local variables moved out from functions;
function parameters removed (passed by global variables)
Compiler 8.00PL3: Tests passed

Code Version: 25T10
Changes made from 25T6: All local variables defined as "static"; function
parameters removed (passed by global variables)
Compiler 8.00PL3: Tests passed
================

To me it's a bug.

Tony


----- Original Message -----
From: "John Temples" <piclist@XARGS.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Tuesday, August 12, 2003 10:05 PM
Subject: Re: [PIC]: Seek C Complier Recommendations


> On Wed, 13 Aug 2003, john chung wrote:
>
> > > unsigned char foo1()
> > > {
> > >     unsigned char i;
> > >     i = 1;
> > >     foo2();
> > >     return i;    // should return 1
> > > }
> > >
> > > void foo2()
> > > {
> > >     unsigned char i;
> > >     // code here...
> > >     i = 2;
> > >     // code here...
> > > }
>
> >       Based on the ANSI C this shouldn't happen. Of course, the compiler
writers could
> > not follow ANSI C....... Not sure about that last statement.
>
> Of course it shouldn't happen.  But there are lots of reasons it can
> happen, and a bug in the compiler is only one of them.  The original
> poster did not claim the above code actually fails.
>
> --
> John W. Temples, III
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.

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