On Fri, May 27, 2016 at 7:05 PM, Francisco Jerez <curroje...@riseup.net>
wrote:
> This will be useful in several places. The only externally visible
> difference (other than non-VGRF files being supported now) is that the
> region sizes are now passed in byte units instead of in GRF units
> because the loss of precision would have become a problem in the SIMD
> lowering pass.
> ---
> .../drivers/dri/i965/brw_fs_copy_propagation.cpp | 16 +++------
> src/mesa/drivers/dri/i965/brw_ir_fs.h | 38
> ++++++++++++++++++++++
> 2 files changed, 42 insertions(+), 12 deletions(-)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> index 38103af..d88d62b 100644
> --- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
> @@ -757,14 +757,6 @@ can_propagate_from(fs_inst *inst)
> !inst->is_partial_write());
> }
>
> -inline bool
> -regions_overlap(const fs_reg &r, unsigned n, const fs_reg &s, unsigned m)
> -{
> - return r.file == s.file && r.nr == s.nr &&
> - !(r.reg_offset + n <= s.reg_offset ||
> - s.reg_offset + m <= r.reg_offset);
> -}
> -
> /* Walks a basic block and does copy propagation on it using the acp
> * list.
> */
> @@ -791,8 +783,8 @@ fs_visitor::opt_copy_propagate_local(void
> *copy_prop_ctx, bblock_t *block,
> /* kill the destination from the ACP */
> if (inst->dst.file == VGRF) {
> foreach_in_list_safe(acp_entry, entry, &acp[inst->dst.nr %
> ACP_HASH_SIZE]) {
> - if (regions_overlap(entry->dst, entry->regs_written,
> - inst->dst, inst->regs_written))
> + if (regions_overlap(entry->dst, entry->regs_written *
> REG_SIZE,
> + inst->dst, inst->regs_written * REG_SIZE))
> entry->remove();
> }
>
> @@ -804,8 +796,8 @@ fs_visitor::opt_copy_propagate_local(void
> *copy_prop_ctx, bblock_t *block,
> /* Make sure we kill the entry if this instruction
> overwrites
> * _any_ of the registers that it reads
> */
> - if (regions_overlap(entry->src, entry->regs_read,
> - inst->dst, inst->regs_written))
> + if (regions_overlap(entry->src, entry->regs_read *
> REG_SIZE,
> + inst->dst, inst->regs_written *
> REG_SIZE))
> entry->remove();
> }
> }
> diff --git a/src/mesa/drivers/dri/i965/brw_ir_fs.h
> b/src/mesa/drivers/dri/i965/brw_ir_fs.h
> index cc1561d..73c6327 100644
> --- a/src/mesa/drivers/dri/i965/brw_ir_fs.h
> +++ b/src/mesa/drivers/dri/i965/brw_ir_fs.h
> @@ -172,6 +172,44 @@ component(fs_reg reg, unsigned idx)
> }
>
> /**
> + * Return an integer identifying the discrete address space a register is
> + * contained in. A register is by definition fully contained in the
> single
> + * reg_space it belongs to, so two registers with different reg_space ids
> are
> + * guaranteed not to overlap. Most register files are a single reg_space
> of
> + * its own, only the VGRF file is composed of multiple discrete address
> + * spaces, one for each VGRF allocation.
> + */
> +static inline uint32_t
> +reg_space(const fs_reg &r)
> +{
> + return r.file << 16 | (r.file == VGRF ? r.nr : 0);
> +}
>
I think I like this concept. It would lead to a bit more compact numbering
if you did "return r.file == VGRF ? r.nr + 8 : r.file". Obviously, you
would probably want to replace "8" with a BRW_NUM_REG_FILES constant.
Given that we really only care about reg_space(r) == reg_space(s) right
now, this is fine.
Reviewed-by: Jason Ekstrand <ja...@jlekstrand.net>
> +
> +/**
> + * Return the base offset in bytes of a register relative to the start of
> its
> + * reg_space().
> + */
> +static inline unsigned
> +reg_offset(const fs_reg &r)
> +{
> + return ((r.file == VGRF || r.file == IMM ? 0 : r.nr) + r.reg_offset) *
> + (r.file == UNIFORM ? 4 : REG_SIZE) + r.subreg_offset;
> +}
> +
> +/**
> + * Return whether the register region starting at \p r and spanning \p dr
> + * bytes could potentially overlap the register region starting at \p s
> and
> + * spanning \p ds bytes.
> + */
> +static inline bool
> +regions_overlap(const fs_reg &r, unsigned dr, const fs_reg &s, unsigned
> ds)
> +{
> + return reg_space(r) == reg_space(s) &&
> + !(reg_offset(r) + dr <= reg_offset(s) ||
> + reg_offset(s) + ds <= reg_offset(r));
> +}
> +
> +/**
> * Return whether the given register region is n-periodic, i.e. whether
> the
> * original region remains invariant after shifting it by \p n scalar
> * channels.
> --
> 2.7.3
>
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