fomit-frame-pointer, Oy

IDE Equivalent

Windows: Optimization > Omit Frame Pointers

Linux: Optimization > Provide Frame Pointer

Mac OS X: Optimization > Provide Frame Pointer

Architectures

-f[no-]omit-frame-pointer: IA-32, Intel® 64 architectures

/Oy[-]: IA-32 architecture

Syntax

Arguments

None

Default

Description

These options determine whether EBP is used as a general-purpose register in optimizations. Options -fomit-frame-pointer and /Oy allow this use. Options -fno-omit-frame-pointer and /Oy- disallow it.

Some debuggers expect EBP to be used as a stack frame pointer, and cannot produce a stack backtrace unless this is so. The -fno-omit-frame-pointer and /Oy- options direct the compiler to generate code that maintains and uses EBP as a stack frame pointer for all functions so that a debugger can still produce a stack backtrace without doing the following:

• For -fno-omit-frame-pointer: turning off optimizations with -O0

• For /Oy-: turning off /O1, /O2, or /O3 optimizations

The -fno-omit-frame-pointer option is set when you specify option -O0 or the -g option. The -fomit-frame-pointer option is set when you specify option -O1, -O2, or -O3.

The /Oy option is set when you specify the /O1, /O2, or /O3 option. Option /Oy- is set when you specify the /Od option.

Using the -fno-omit-frame-pointer or /Oy- option reduces the number of available general-purpose registers by 1, and can result in slightly less efficient code.

Note

There is currently an issue with GCC 3.2 exception handling. Therefore, the Intel compiler ignores this option when GCC 3.2 is installed for C++ and exception handling is turned on (the default).

Alternate Options

Linux and Mac OS X: -fp (this is a deprecated option)

Windows: None