[Mesa-dev] [PATCH 04/11] nir: Add a function for rewriting instruction destinations

[Michael Schellenberger Costa]

Hi,
Am 10/09/2015 um 02:50 schrieb Jason Ekstrand:
> ---
>  src/glsl/nir/nir.c | 24 ++++++++++++++++++++++++
>  src/glsl/nir/nir.h |  2 ++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/src/glsl/nir/nir.c b/src/glsl/nir/nir.c
> index e173b21..0090b08 100644
> --- a/src/glsl/nir/nir.c
> +++ b/src/glsl/nir/nir.c
> @@ -1175,6 +1175,30 @@ nir_if_rewrite_condition(nir_if *if_stmt, nir_src new_src)
>  }
>  
>  void
> +nir_instr_rewrite_dest(nir_instr *instr, nir_dest *dest, nir_dest new_dest)
> +{
> +   if (dest->is_ssa) {
> +      /* We can only overwrite an SSA destination if it has no uses. */
> +      assert(list_empty(&dest->ssa.uses) && list_empty(&dest->ssa.if_uses));
> +   } else {
> +      list_del(&dest->reg.def_link);
> +      if (dest->reg.indirect)
> +         src_remove_all_uses(dest->reg.indirect);
> +   }
> +
> +   /* We can't re-write with an SSA def */
> +   assert(!new_dest.is_ssa);
Wouldn't it make more sense to check that assert first, as the if clause
above may include some work

Michael
> +
> +   nir_dest_copy(dest, &new_dest, instr);
> +
> +   dest->reg.parent_instr = instr;
> +   list_addtail(&dest->reg.def_link, &new_dest.reg.reg->defs);
> +
> +   if (dest->reg.indirect)
> +      src_add_all_uses(dest->reg.indirect, instr, NULL);
> +}
> +
> +void
>  nir_ssa_def_init(nir_instr *instr, nir_ssa_def *def,
>                   unsigned num_components, const char *name)
>  {
> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> index 32c338c..a8e7363 100644
> --- a/src/glsl/nir/nir.h
> +++ b/src/glsl/nir/nir.h
> @@ -1725,6 +1725,8 @@ bool nir_srcs_equal(nir_src src1, nir_src src2);
>  void nir_instr_rewrite_src(nir_instr *instr, nir_src *src, nir_src new_src);
>  void nir_instr_move_src(nir_instr *dest_instr, nir_src *dest, nir_src *src);
>  void nir_if_rewrite_condition(nir_if *if_stmt, nir_src new_src);
> +void nir_instr_rewrite_dest(nir_instr *instr, nir_dest *dest,
> +                            nir_dest new_dest);
>  
>  void nir_ssa_dest_init(nir_instr *instr, nir_dest *dest,
>                         unsigned num_components, const char *name);
>