FIX: C1001: main.c, Line 826 or 831 From Optimization

The information in this article applies to:

• The Microsoft C/C++ Compiler (CL.EXE), included with:

      - Microsoft C/C++ for MS-DOS, versions 7.0
      - Microsoft Visual C++ for Windows, version 1.0
  

SYMPTOMS

An attempt to compile the code example provided below with the /f- and /Oi compiler options specified fails and Microsoft C/C++ generates one of the following messages. For Microsoft C/C++ version 8.0:

   fatal error C1001: internal compiler error
   (compiler file '@(#)main.c:1.27', line 831)

   fatal error C1001: INTERNAL COMPILER ERROR
   (compiler file '@(#)main.c:1.27', line 826)

RESOLUTION

There are three methods to work around this problem, as follows:

• Edit the compiler command line to remove the /Oi option switch.
• Use #pragma optimize to disable optimizations from the function that causes the problem. The code example below demonstrates the appropriate pragma.
• Compile the application with the fast compiler (specify /f on the compiler command line) instead of the optimizing compiler (specify /f- on the compiler command line).

STATUS

Microsoft has confirmed this to be a problem in C/C++ versions 7.0 and 8.0 for MS-DOS. This problem was corrected in C/C++ version 8.0c for MS-DOS, included with Visual C++ for Windows version 1.5.

MORE INFORMATION

The following code example demonstrates this error. You can work around this problem by removing the comment from the #pragma optimize statements in the code below.

Sample Code

/*
 * Compile options needed: /f- /Oi
 */

// #pragma optimize("", off);

   double y = 0.0;

   if (x == 0.0)
      dt = 1.0;
   else
      _asm  f2xm1
   return y;

// #pragma optimize("", on);