[PATCH/AARCH64] Decimal floating point support for AARCH64

[Andrew Pinski <apinski at cavium dot com>]

Hi,
  This patch adds Decimal floating point support to aarch64.  It is
the base support in that since there is no hardware support for DFP,
it just defines the ABI.  The ABI I chose is that _Decimal32 is
treated like float, _Decimal64 is treated like double and _Decimal128
is treated like long double.  In that they are passed via the floating
registers (sN, dN, qN).
Is this ok an ABI?

Is the patch ok?  Bootstrapped and tested on aarch64-linux-gnu with
--enable-decimal-float with no regressions and all of the dfp
testcases pass.

Thanks,
Andrew Pinski

gcc/ChangeLog:
* config/aarch64/aarch64.c (aarch64_split_128bit_move): Handle TDmode.
(aarch64_classify_address): Likewise.
(aarch64_legitimize_address_displacement): Likewise.
(aarch64_legitimize_address): Likewise.
(aarch64_constant_pool_reload_icode): Handle SD, DD, and TD modes.
(aarch64_secondary_reload): Handle TDmode.
(aarch64_valid_floating_const): For decimal floating point return false.
(aarch64_gimplify_va_arg_expr): Handle SD, DD, and TD modes.
(aapcs_vfp_sub_candidate): Likewise.
(aarch64_vfp_is_call_or_return_candidate): Handle MODE_DECIMAL_FLOAT.
(aarch64_scalar_mode_supported_p): For DECIMAL_FLOAT_MODE_P, return
default_decimal_float_supported_p.
* config/aarch64/iterators.md (GPF_TF_F16): Add SD, DD, and TD modes.
(SFD): New iterator.
(DFD): New iterator.
(TFD): New iterator.
(GPF_TF): Add SD, DD, and TD modes.
(TX): Add TD mode.
* config/aarch64/aarch64.md (*movsf_aarch64): Use SFD iterator.
(*movdf_aarch64): Use DFD iterator.
(*movtf_aarch64): Use TFD iterator.
(define_split for TF): Use TFD iterator.


gcc/testsuite/ChangeLog:
* c-c++-common/dfp/pr39986.c: Allow for word instead of just long.

libgcc/ChangeLog:
* config.host (aarch64*-*-elf): Add t-dfprules to tmake_file.
(aarch64*-*-freebsd*): Likewise.
(aarch64*-*-linux*): Likewise.

Attachment: current-dfp.diff.txt
Description: Text document