How to suppress frame pointer usage by default?

[Ian Lance Taylor]

Konstantin Vladimirov <konstantin.vladimirov@gmail.com> writes:

> What one must use in custom backend to suppress frame pointer usage by default?
>
> Frame pointer is mentioned in ELIMINABLE_REGS:
>
> #define ELIMINABLE_REGS             \
> {           \
>   {ARG_POINTER_REGNUM,   STACK_POINTER_REGNUM}, \
>   {ARG_POINTER_REGNUM,   FRAME_POINTER_REGNUM}, \
>   {FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM}, \
> }
>
> TARGET_CAN_ELIMINATE is defined to be always true,
>
> TARGET_FRAME_POINTER_REQUIRED is defined to be always false
>
> Instead of this, gcc generates code with frame pointer usage, and I
> need manually specify -fomit-frame-pointer to suppress this behavior.
> What else may influence this?

You may need to set flag_omit_frame_pointer in your
TARGET_OPTION_OVERRIDE or TARGET_OPTION_OPTIMIZATION_TABLE or
TARGET_OPTION_OVERRIDE (note that these have different names in earlier
versions of gcc).

Ian