[Mesa-dev] [PATCH 06/12] nir/cse: Properly handle nir_ssa_def.exact

[Francisco Jerez]

Jason Ekstrand <jason at jlekstrand.net> writes:

> ---
>  src/compiler/nir/nir_instr_set.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/src/compiler/nir/nir_instr_set.c b/src/compiler/nir/nir_instr_set.c
> index 159ded0..00e4784 100644
> --- a/src/compiler/nir/nir_instr_set.c
> +++ b/src/compiler/nir/nir_instr_set.c
> @@ -52,6 +52,7 @@ hash_alu(uint32_t hash, const nir_alu_instr *instr)
>  {
>     hash = HASH(hash, instr->op);
>     hash = HASH(hash, instr->dest.dest.ssa.num_components);
> +   /* We explicitly don't hash instr->dest.dest.exact */
>  
>     if (nir_op_infos[instr->op].algebraic_properties & NIR_OP_IS_COMMUTATIVE) {
>        assert(nir_op_infos[instr->op].num_inputs == 2);
> @@ -267,6 +268,8 @@ nir_instrs_equal(const nir_instr *instr1, const nir_instr *instr2)
>        if (alu1->dest.dest.ssa.num_components != alu2->dest.dest.ssa.num_components)
>           return false;
>  
> +      /* We explicitly don't hash instr->dest.dest.exact */
> +
>        if (nir_op_infos[alu1->op].algebraic_properties & NIR_OP_IS_COMMUTATIVE) {
>           assert(nir_op_infos[alu1->op].num_inputs == 2);
>           return (nir_alu_srcs_equal(alu1, alu2, 0, 0) &&
> @@ -496,8 +499,17 @@ nir_instr_set_add_or_rewrite(struct set *instr_set, nir_instr *instr)
>     struct set_entry *entry = _mesa_set_search(instr_set, instr);
>     if (entry) {
>        nir_ssa_def *def = nir_instr_get_dest_ssa_def(instr);
> -      nir_ssa_def *new_def =
> -         nir_instr_get_dest_ssa_def((nir_instr *) entry->key);
> +      nir_instr *match = (nir_instr *) entry->key;
> +      nir_ssa_def *new_def = nir_instr_get_dest_ssa_def(match);
> +
> +      /* It's safe to replace a exact instruction with an inexact one as
> +       * long as we make it exact.  If we got here, the two instructions are
> +       * exactly identical in every other way so, once we've set the exact
> +       * bit, they are the same.
> +       */
> +      if (instr->type == nir_instr_type_alu && nir_instr_as_alu(instr)->exact)
> +         nir_instr_as_alu(match)->exact = true;
> +

Reviewed-by: Francisco Jerez <currojerez at riseup.net>

>        nir_ssa_def_rewrite_uses(def, nir_src_for_ssa(new_def));
>        return true;
>     }
> -- 
> 2.5.0.400.gff86faf
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
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