[Bug target/116521] missing optimization: xtensa tail-call

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116521

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The default ABI for xtensa is to use windowed registers which does not
currently support sibcalling.

include/xtensa-config.h :
#define XSHAL_ABI                       XTHAL_ABI_WINDOWED
#define XTHAL_ABI_WINDOWED              0

gcc/config/xtensa/xtensa.h:
#define TARGET_WINDOWED_ABI_DEFAULT (XSHAL_ABI == XTHAL_ABI_WINDOWED)

gcc/config/xtensa/xtensa.cc:

  if (xtensa_windowed_abi == -1)
    xtensa_windowed_abi = TARGET_WINDOWED_ABI_DEFAULT;

  /* Do not allow sibcalls when windowed registers ABI is in effect.  */
  if (TARGET_WINDOWED_ABI)
    return false;