[Bug rtl-optimization/54342] [4.8 Regression] Wrong mode of call argument

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54342

--- Comment #9 from H.J. Lu <hjl.tools at gmail dot com> 2012-08-23 13:58:15 UTC ---
(In reply to comment #4)
> I believe that OImode is currently handled inconsistently in the compiler, and
> should be handled exactly in the way TImode is handled for xmm registers.
> 
> There are some examples:
> 
> -function_pass_avx256_p: OImode is handled together with VALID_AVX256_REG_MODE
> in parallels, but not in registers.
> -construct_container: OImode is created for container member
> -ix86_hard_regno_mode_ok: OImode is handled together with
> VALID_AVX256_REG_MODE.

It is done on purpose.  GCC needs an integer mode which
is as wide as vector size for internal usage.

> I think that OImode should be a member of VALID_AVX256_REG_MODE.

If we want to do that, we need first to update psABI to specify how
to pass and return OImode.