The SVE support for the new CONST_VECTOR encoding needs to be able
to extract the first N bits of the vector and duplicate it. This patch
adds a simplify_subreg rule for that.
The code is covered by the gcc.target/aarch64/sve_slp_*.c tests.
2018-01-13 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
* simplify-rtx.c (simplify_immed_subreg): Add an inner_bytes
parameter and use it instead of GET_MODE_SIZE (innermode). Use
inner_bytes * BITS_PER_UNIT instead of GET_MODE_BITSIZE (innermode).
Use CEIL (inner_bytes, GET_MODE_UNIT_SIZE (innermode)) instead of
GET_MODE_NUNITS (innermode). Also add a first_elem parameter.
Change innermode from fixed_mode_size to machine_mode.
(simplify_subreg): Update call accordingly. Handle a constant-sized
subreg of a variable-length CONST_VECTOR.
From-SVN: r256610
