Re: [MIPS64] Problems when Passing TImode Parameters in EABI

[Richard Sandiford <richard at codesourcery dot com>]

"Fu, Chao-Ying" <fu@mips.com> writes:
>   I think there is a bug in mips_pass_by_reference when the mips abi
> is EABI to pass TImode parameters.

Good catch.

>   Does someone know how to pass TImode parameters in EABI?  Thanks!

I imagine this case wasn't specifically considered.  The EABI calls
for double-word integers to be passed by value on 32-bit targets,
so if 128-bit integers had been considered, I imagine the EABI
would call for them to be handled in the same way on 64-bit targets.

As it is, the EABI uses stack passing as the fallback case for
"parameters not otherwise handled above".  So I think the type
!= NULL case is doing the right thing.  Sticking with it also
has the advantage that it wouldn't break backward compatiblity
for cases that currently work.  I don't think this particular
case has ever worked for libcalls.

I'll whip up a patch tonight.  I imagine this is also the reason for the
gcc.dg/torture/fp-int-convert-timode.c failures on mipsisa64-elf, which
I haven't had the spare time to look at yet.

Richard