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Q61055: C1001: Internal Compiler Error: regMD.c: 1.100 Line 1017

Article: Q61055
Product(s): See article
Version(s): 6.00   | 6.00
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | buglist6.00 | mspl13_c
Last Modified: 15-MAY-1990

The following sample code generates an internal compiler error when
compiled with /Ole for optimizations in all memory models:

   prog.c(15) : fatal error C1001: Internal Compiler Error
                    (Compiler file '@(#)regMD.c:1.100', line 1017
                    Contact Microsoft Product Support Services

Sample Code
-----------

 1:  void foo (unsigned);
 2:
 3:  /* Either of the following two pragmas are valid workarounds. */
 4:  /* #pragma optimize ("l", off) */
 5:  /* #pragma optimize ("e", off) */
 6:
 7:  void foo (unsigned start)
 8:      {   /* Works if "start" is an "int" instead of "unsigned" */
 9:      int i;
10:      int end;
11:
12:      end = start + 8;       /* Works if "end = start" or if
13:                                "end" is assigned to a constant */
14:
15:       for (i = start; i < end; ++i)
16:           end++;             /* Works if empty statement or i++ */
17:      }
18:
19:  /* #pragma optimize ("l", on) */
20:  /* #pragma optimize ("e", on) */

To work around this problem, disable either the global register
allocation /Oe or the loop optimization /Ol. There is a conflict with
both optimizations being enabled at the same time with this particular
code.

The following are two additional workarounds:

1. Use the optimize() pragma to override the compiler's optimization
   switch (as shown in the above program).

   You can disable one of the optimizations before the function that
   contains the offending statement, and then re-enable the
   optimization after the closing curly brace (}) of the function.

   With this method, you gain the optimum performance available for
   your source code.

2. Use -Ol or -Oe instead of -Ole.

Microsoft has confirmed this to be a problem with Version 6.00. We are
researching this problem and will post new information here as it
becomes available.

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