FIX: "Fatal Error C1001" Error Message When You Compile Code with While Loop (320004)

The information in this article applies to:

Microsoft Visual C++ .NET (2002)

This article was previously published under Q320004

SYMPTOMS

When you try to compile code that is similar to the sample code included in the "Steps to Reproduce the Problem" section of this article, you may receive the following error message:

"fatal error C1001: INTERNAL COMPILER ERROR

(compiler file 'f:\vs70builds\9466\vc\Compiler\Utc\src\P2\main.c', line 146)"

CAUSE

This behavior occurs because the optimizing compiler cannot optimize the while loop.

RESOLUTION

To work around the issue, use one of the following methods:

Turn off the /Og switch for the function by using the following command:
#pragma optimize("g",off)
-or-
Declare the function parameter start to be volatile.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article. This bug was corrected in Microsoft Visual C++ .NET (2003).

MORE INFORMATION

Steps to Reproduce the Problem

Try to compile the following code:

//test.cpp
// Compiler Option: cl /c /Og test.cpp

union Pixel{
    char code8;
} ;

struct RGB {
    double r;
  };
//#pragma optimize("g",off)//WORKAROUND 1

void func(   char *start, char *end)
//void func(   volatile char *start, char *end) //WORKAROUND 2
{
     RGB map[256];
     Pixel s[16];

    while (start < end) {
      *start++ = s[(int)((map[*start].r))].code8;

    }
}
#pragma optimize("",on) //WORKAROUND 1

You receive the error message described in the "Symptoms" section of this article.

Modification Type:	Minor	Last Reviewed:	7/5/2005
Keywords:	kbfix kbbug kbCompiler kberrmsg kbpending KB320004