This patch adds a fixed_size_mode machine_mode wrapper
for modes that are known to have a fixed size. That applies
to all current modes, but future patches will add support for
variable-sized modes.
The use of this class should be pretty restricted. One important
use case is to hold the mode of static data, which can never be
variable-sized with current file formats. Another is to hold
the modes of registers involved in __builtin_apply and
__builtin_result, since those interfaces don't cope well with
variable-sized data.
The class can also be useful when reinterpreting the contents of
a fixed-length bit string as a different kind of value.
2017-11-01 Richard Sandiford <richard.sandiford@linaro.org>
Alan Hayward <alan.hayward@arm.com>
David Sherwood <david.sherwood@arm.com>
gcc/
* machmode.h (fixed_size_mode): New class.
* rtl.h (get_pool_mode): Return fixed_size_mode.
* gengtype.c (main): Add fixed_size_mode.
* target.def (get_raw_result_mode): Return a fixed_size_mode.
(get_raw_arg_mode): Likewise.
* doc/tm.texi: Regenerate.
* targhooks.h (default_get_reg_raw_mode): Return a fixed_size_mode.
* targhooks.c (default_get_reg_raw_mode): Likewise.
* config/ia64/ia64.c (ia64_get_reg_raw_mode): Likewise.
* config/mips/mips.c (mips_get_reg_raw_mode): Likewise.
* config/msp430/msp430.c (msp430_get_raw_arg_mode): Likewise.
(msp430_get_raw_result_mode): Likewise.
* config/avr/avr-protos.h (regmask): Use as_a <fixed_side_mode>
* dbxout.c (dbxout_parms): Require fixed-size modes.
* expr.c (copy_blkmode_from_reg, copy_blkmode_to_reg): Likewise.
* gimple-ssa-store-merging.c (encode_tree_to_bitpos): Likewise.
* omp-low.c (lower_oacc_reductions): Likewise.
* simplify-rtx.c (simplify_immed_subreg): Take fixed_size_modes.
(simplify_subreg): Update accordingly.
* varasm.c (constant_descriptor_rtx::mode): Change to fixed_size_mode.
(force_const_mem): Update accordingly. Return NULL_RTX for modes
that aren't fixed-size.
(get_pool_mode): Return a fixed_size_mode.
(output_constant_pool_2): Take a fixed_size_mode.
Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r254300
