Hello!

Attached patch corrects handing of split _Complex float variable
arguments. Alpha is not able to pass 32bit floats in float registers
as variable arguments (see the comment in alpha_pass_by_reference), so
we pass them by reference. However, complex float arguments are split
to their real and imaginary part and passed separately. When passed by
reference, every part is passed separately by a separate reference.
Attached patch fixes this oversight in alpha_gimplify_va_arg.

The patch fixes:

FAIL: gcc.dg/compat/scalar-by-value-4 c_compat_x_tst.o-c_compat_y_tst.o execute
FAIL: gcc.dg/compat/scalar-return-4 c_compat_x_tst.o-c_compat_y_tst.o execute

2019-01-16  Uroš Bizjak  <ubizjak@gmail.com>

    * config/alpha/alpha.c (alpha_gimplify_va_arg):
    Handle split indirect COMPLEX_TYPE arguments.

Bootstrapped and regression tested on alphaev68-linux-gnu.

Committed to mainline SVN.

Uros.