/Zi Causes Code Motion Optimization Suppression

MS-DOS                 | OS/2       | WINDOWS

The information in this article applies to:

 The Microsoft C/C++ Compiler (CL.EXE), supplied with:
  - Microsoft C for MS-DOS, versions 6.0, 6.0a, and 6.0ax
  - Microsoft C for OS/2, versions 6.0, and 6.0a
  - Microsoft C/C++ for MS-DOS, version 7.0
  - Microsoft Visual C++ for Windows, version 1.0 and 1.5

SUMMARY

In Microsoft C, using the full optimizing compiler with /Zi and no other switches causes certain code motion optimizations to be suppressed (that is, the code generated for a program with the defaults and with /Zi may differ).

You can override this default behavior by explicitly specifying the default optimizations on the command line. For example, you can compile with the following command line to get the same code with or without /Zi:

   For C versions 6.0, 6.0a, and 6.0ax:

      cl /Zi /Ot file.c

   For C/C++ version 7.0 and Visual C++ 1.0 and 1.5:

      cl /f- /Zi /Ot file.c

NOTE: This does not occur with the Microsoft 32-bit compilers.