Microsoft KB Archive/172992

= FIX: /Og Causes C1001 While Looping =

Article ID: 172992

Article Last Modified on 7/5/2005

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APPLIES TO


 * Microsoft Visual C++ 5.0 Enterprise Edition
 * Microsoft Visual C++ 5.0 Professional Edition

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This article was previously published under Q172992



SYMPTOMS
Compiling code similar to the code in the sample below may cause the following error to be generated:

fatal error C1001: INTERNAL COMPILER ERROR (compiler file 'E:\utc\src\\P2\main.c', line 379)



RESOLUTION
One way to work around the C1001 error is to correct the apparent programming error in the sample code below. Notice the check of p==0 in the if statement. The code that follows will cause an access violation if executed. Changing the check to p!=0 will cause the compiler to not generate the C1001 error and allow the code to compile. Another workaround that preserves the apparently incorrect algorithm is to introduce a local integer that holds the result of the comparison of p to zero. Use this local integer in the if statement instead of the actual comparison.



STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in Visual Studio 97 Service Pack 3.

For additional information about the Visual Studio 97 Service Pack 3, please see the following article in the Microsoft Knowledge Base:

170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why



Sample
// compile options: /Og /c int f( int * p ) {     int i = 1; // int i2 = (p==0); // uncomment these 2 lines and // if( i2 )        // if( p == 0 )       // comment this one for workaround {        while( i && *p != 0 ) {           i = *p++ == 3; }     }      return i;   }

Additional query words: ICE

Keywords: kberrmsg kbbug kbfix kbvs97sp2fix kbcompiler KB172992

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