Re: [PATCH][GCC][AArch64] optimize float immediate moves (2 /4) - HF/DF/SF mode.

[Richard Sandiford <richard.sandiford@linaro.org>]

In addition to James's comments:

Tamar Christina <Tamar.Christina@arm.com> writes:
> +  [(const_int 0)]
> +  "{

"{ ... }" isn't necessary, we can just use { ... }

> +    unsigned HOST_WIDE_INT ival;
> +    if (!aarch64_reinterpret_float_as_int (operands[1], &ival))
> +      FAIL;
> +
> +    rtx tmp = gen_reg_rtx (SImode);
> +    aarch64_expand_mov_immediate (tmp, gen_int_mode (ival, SImode));
> +    tmp = simplify_gen_subreg (HImode, tmp, SImode, 0);

This looks wrong for big-endian, and...

> +    emit_move_insn (operands[0], gen_lowpart (HFmode, tmp));

...either it should be OK to go directly from tmp to the HFmode lowpart,
or we should move the HImode temporary into a fresh REG.  Current
validate_subreg seems to suggest that we need the latter.

Isn't it possible to use a HImode move immediate instead of an SImode one?

Thanks,
Richard