[Mesa-dev] [PATCH 2/4] nir: turn ssa check into an assert

[Ian Romanick]

On 2/13/19 12:00 AM, Timothy Arceri wrote:
> Everthing should be in ssa form when this is called. Checking
> for it here is expensive so turn this into an assert instead.
> 
> Do the cheap thing first and check if we can even progress with
> this instruction type.
> ---
>  src/compiler/nir/nir_instr_set.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/src/compiler/nir/nir_instr_set.c b/src/compiler/nir/nir_instr_set.c
> index 61476c0b03f..c795efbca6a 100644
> --- a/src/compiler/nir/nir_instr_set.c
> +++ b/src/compiler/nir/nir_instr_set.c
> @@ -498,6 +498,16 @@ dest_is_ssa(nir_dest *dest, void *data)
>     return dest->is_ssa;
>  }
>  
> +static bool
> +instr_each_src_and_dest_is_ssa(nir_instr *instr)
> +{
> +   if (!nir_foreach_dest(instr, dest_is_ssa, NULL) ||
> +       !nir_foreach_src(instr, src_is_ssa, NULL))
> +      return false;
> +
> +   return true;

I get that this is trying to be obvious about just moving code, but I'd
like this a lot better if it more directly matched the name:

   return nir_foreach_dest(instr, dest_is_ssa, NULL) &&
          nir_foreach_src(instr, src_is_ssa, NULL);

> +}
> +
>  /* This function determines if uses of an instruction can safely be rewritten
>   * to use another identical instruction instead. Note that this function must
>   * be kept in sync with hash_instr() and nir_instrs_equal() -- only
> @@ -509,9 +519,7 @@ static bool
>  instr_can_rewrite(nir_instr *instr)
>  {
>     /* We only handle SSA. */
> -   if (!nir_foreach_dest(instr, dest_is_ssa, NULL) ||
> -       !nir_foreach_src(instr, src_is_ssa, NULL))
> -      return false;
> +   assert(instr_each_src_and_dest_is_ssa(instr));
>  
>     switch (instr->type) {
>     case nir_instr_type_alu: