[Mesa-dev] [PATCH 2/4] glsl: fix bitfield_insert use when doing ldexp lowering

[Ilia Mirkin]

On Fri, Apr 25, 2014 at 2:38 PM, Matt Turner <mattst88 at gmail.com> wrote:
> On Fri, Apr 25, 2014 at 10:41 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>> bitfield_insert expects glsl_type::int_type arguments, not uint vectors
>>
>> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
>> ---
>>
>> Identical to the patch I sent out last night. Without it ldexp lowering
>> (without bfi lowering) causes assertion failures in the next mesa/st patch.
>>
>>  src/glsl/lower_instructions.cpp | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/glsl/lower_instructions.cpp b/src/glsl/lower_instructions.cpp
>> index 01ea0f0..54a7a23 100644
>> --- a/src/glsl/lower_instructions.cpp
>> +++ b/src/glsl/lower_instructions.cpp
>> @@ -360,7 +360,8 @@ lower_instructions_visitor::ldexp_to_arith(ir_expression *ir)
>>     ir_constant *sign_mask = new(ir) ir_constant(0x80000000u, vec_elem);
>>
>>     ir_constant *exp_shift = new(ir) ir_constant(23u, vec_elem);
>> -   ir_constant *exp_width = new(ir) ir_constant(8u, vec_elem);
>> +   ir_constant *exp_shift_int = new(ir) ir_constant(23);
>> +   ir_constant *exp_width = new(ir) ir_constant(8);
>>
>>     /* Temporary variables */
>>     ir_variable *x = new(ir) ir_variable(ir->type, "x", ir_var_temporary);
>> @@ -421,10 +422,9 @@ lower_instructions_visitor::ldexp_to_arith(ir_expression *ir)
>>      *     floating-point type, the result is undefined."
>>      */
>>
>> -   ir_constant *exp_shift_clone = exp_shift->clone(ir, NULL);
>>     ir->operation = ir_unop_bitcast_i2f;
>>     ir->operands[0] = bitfield_insert(bitcast_f2i(x), resulting_biased_exp,
>> -                                     exp_shift_clone, exp_width);
>> +                                     exp_shift_int, exp_width);
>>     ir->operands[1] = NULL;
>>
>>     /* Don't generate new IR that would need to be lowered in an additional
>> --
>> 1.8.3.2
>
> Interesting. Yeah, this is wrong. I was wondering why I wasn't seeing
> a problem, but it's because i965 lowers bitfield_insert and presumably
> your driver doesn't.
>
> I can't reproduce the issue, but can't you just do this? If so, I'll
> send a patch.

I'll check. I assumed you couldn't because exp_shift was being used by
something else and that it would complain with the non-vector
argument. But I never tried it, will do and let you know in a bit.

>
> diff --git a/src/glsl/lower_instructions.cpp b/src/glsl/lower_instructions.cpp
> index 01ea0f0..49316d0 100644
> --- a/src/glsl/lower_instructions.cpp
> +++ b/src/glsl/lower_instructions.cpp
> @@ -359,8 +359,8 @@
> lower_instructions_visitor::ldexp_to_arith(ir_expression *ir)
>
>     ir_constant *sign_mask = new(ir) ir_constant(0x80000000u, vec_elem);
>
> -   ir_constant *exp_shift = new(ir) ir_constant(23u, vec_elem);
> -   ir_constant *exp_width = new(ir) ir_constant(8u, vec_elem);
> +   ir_constant *exp_shift = new(ir) ir_constant(23);
> +   ir_constant *exp_width = new(ir) ir_constant(8);
>
>     /* Temporary variables */
>     ir_variable *x = new(ir) ir_variable(ir->type, "x", ir_var_temporary);