On 7/10/24 9:44 AM, Richard Sandiford wrote:
expand_fn_using_insn has code to handle SUBREG_PROMOTED_VAR_P
destinations. Specifically, for:
(subreg/v:M1 (reg:M2 R) ...)
it creates a new temporary register T, uses it for the output
operand, then sign- or zero-extends the M1 lowpart of T to M2,
storing the result in R.
This patch splits this handling out into helper routines and
uses them for other instances of:
if (!rtx_equal_p (target, ops[0].value))
emit_move_insn (target, ops[0].value);
It's quite probable that this doesn't help any of the other cases;
in particular, it shouldn't affect vectors. But I think it could
be useful for the CRC work.
Bootstrapped & regression-tested on aarch64-linux-gnu. OK to install?
Richard
gcc/
* internal-fn.cc (create_call_lhs_operand, assign_call_lhs): New
functions, split out from...
(expand_fn_using_insn): ...here.
(expand_load_lanes_optab_fn): Use them.
(expand_GOMP_SIMT_ENTER_ALLOC): Likewise.
(expand_GOMP_SIMT_LAST_LANE): Likewise.
(expand_GOMP_SIMT_ORDERED_PRED): Likewise.
(expand_GOMP_SIMT_VOTE_ANY): Likewise.
(expand_GOMP_SIMT_XCHG_BFLY): Likewise.
(expand_GOMP_SIMT_XCHG_IDX): Likewise.
(expand_partial_load_optab_fn): Likewise.
(expand_vec_cond_optab_fn): Likewise.
(expand_vec_cond_mask_optab_fn): Likewise.
(expand_RAWMEMCHR): Likewise.
(expand_gather_load_optab_fn): Likewise.
(expand_while_optab_fn): Likewise.
(expand_SPACESHIP): Likewise.
OK.
FWIW, we did some testing for cases where we didn't utilize the
SUBREG_PROMOTED* bits to eliminate extensions coming out of the
expansion phase. For the most part we're doing a good job. IIRC our
instrumentation showed they tended to sneak in mostly through expansion
of builtins (particularly the arithemtic overflow builtins).
Jeff
