[Beignet] [PATCH] fix a powr function issue in cpu compiler math
Matt Turner
mattst88 at gmail.com
Wed Jul 29 10:37:21 PDT 2015
On Sun, Jul 19, 2015 at 6:33 AM, Meng Mengmeng <mengmeng.meng at intel.com> wrote:
> In OpenCL spec, gentype powr(gentype x, gentype y). In the meantime,
> added edge tests for powr.
> ---
> utests/utest_math_gen.py | 24 ++++++++++++++++++++----
> 1 file changed, 20 insertions(+), 4 deletions(-)
>
> diff --git a/utests/utest_math_gen.py b/utests/utest_math_gen.py
> index 83edcc3..24ddaa4 100755
> --- a/utests/utest_math_gen.py
> +++ b/utests/utest_math_gen.py
> @@ -467,14 +467,30 @@ static float pown(float x, int y){
> pownUtests = func('pown','pown',[pown_input_type1,pown_input_type2],pown_output_type,[pown_input_values1,pown_input_values2],'16 * FLT_ULP', pown_cpu_func)
>
> ##### gentype powr(gentype x, gentype y)
> - powr_input_values1 = [80, -80, 3.14, -3.14, 0.5, 1, -1, 0.0,6,1500.24,-1500.24]
> - powr_input_values2 = [5,6,7,8,10,11,12,13,14,0,12]
> + powr_input_values1 = [80,-80,3.14,1, 1.257,+0, -0,+0,-0, +0, -0, +1, +1, -80, 0,-0,0,-0, 'INFINITY','INFINITY',+1,+1,0,2.5,'NAN','NAN','NAN' ]
> + powr_input_values2 = [5.5,6,7, +0,-0,-1,-15.67,'-INFINITY', '-INFINITY',1, -2.7,10.5, 3.1415,3.5,-0,-0,0,0, 0, -0,'INFINITY','-INFINITY','NAN','NAN',-1.5,0,1.5]
> powr_input_type1 = ['float','float2','float4','float8','float16']
> powr_input_type2 = ['float','float2','float4','float8','float16']
> powr_output_type = ['float','float2','float4','float8','float16']
> powr_cpu_func='''
> -static float powr(float x, int y){
> - if (x<0)
> +static float powr(float x, float y){
> + if (((x > 0) && (x != +INFINITY)) &&((y == -0) || (y == -0)))
Space after &&. I think you meant (y == +0) here, but I have more
comments below about this.
> + return 1;
> + else if (((x == +0) || (x == -0)) && ((y <0) || (y == -INFINITY)))
Space after <
> + return +INFINITY;
> + else if (((x == +0) || (x == -0)) && (y > 0))
> + return +0;
> + else if (((x == +0) || (x == -0)) && ((y == +0) || (y == -0)))
> + return NAN;
> + else if ((x == +1) && ((y == +INFINITY) || (y == -INFINITY)))
> + return NAN;
> + else if ((x == +1) && ((y != +INFINITY) && (y != -INFINITY)))
> + return 1;
> + else if ((x == +INFINITY) && ((y == +0) || (y == -0)))
This pattern of (y == +0) || (y == -0) is meaningless for a few reasons:
Float == comparison against 0.0f is true if the float is positive or
negative 0.0f. There's no need to test for +0.0f and -0.0f separately.
Also, the literals you've used ("+0", "-0") are integers which are
implicitly promoted to float, and since there isn't a negative-zero
integer representation, they both evaluate to (y == 0.0f)... which as
I said already handles both positive and negative zero.
The code should simply be (y == 0.0f). (The expression y == 0.0
implicitly promotes y to a double since 0.0 without the suffix is
double-precision)
> + return NAN;
> + else if (isnan(x) || (x < 0))
> + return NAN;
> + else if ((x >= 0) && (isnan(y)))
> return NAN;
> else
> return powf(x,y);
> --
> 1.9.1
>
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