Thanks Fengyang
On Saturday, October 8, 2016 at 12:39:42 AM UTC-3, Fengyang Wang wrote:
>
> As Jussi Piitulainen noted, the ^ operator is backwards, so you need to
> wrap it around a function.
>
> On Friday, October 7, 2016 at 10:05:34 AM UTC-4, Kevin Liu wrote:
>>
>> *julia> **@code_native(b^a)*
>>
>> .section __TEXT,__text,regular,pure_instructions
>>
>> Filename: bool.jl
>>
>> Source line: 39
>>
>> pushq %rbp
>>
>> movq %rsp, %rbp
>>
>> Source line: 39
>>
>> xorb $1, %sil
>>
>> orb %dil, %sil
>>
>> movb %sil, %al
>>
>> popq %rbp
>>
>> ret
>>
>> *julia> **@code_native(a<=b)*
>>
>> .section __TEXT,__text,regular,pure_instructions
>>
>> Filename: bool.jl
>>
>> Source line: 29
>>
>> pushq %rbp
>>
>> movq %rsp, %rbp
>>
>> Source line: 29
>>
>> xorb $1, %dil
>>
>> orb %sil, %dil
>>
>> movb %dil, %al
>>
>> popq %rbp
>>
>> ret
>>
>> *julia> **@code_native(ifelse(a,b,true))*
>>
>> .section __TEXT,__text,regular,pure_instructions
>>
>> Filename: operators.jl
>>
>> Source line: 48
>>
>> pushq %rbp
>>
>> movq %rsp, %rbp
>>
>> testb $1, %dil
>>
>> Source line: 48
>>
>> jne L17
>>
>> movb %dl, %sil
>>
>> L17: movb %sil, %al
>>
>> popq %rbp
>>
>> ret
>>
>>
>>
>> On Friday, October 7, 2016 at 10:58:34 AM UTC-3, Kevin Liu wrote:
>>>
>>> *julia> **@code_llvm(b^a)*
>>>
>>>
>>> define i1 @"julia_^_21646"(i1, i1) {
>>>
>>> top:
>>>
>>> %2 = xor i1 %1, true
>>>
>>> %3 = or i1 %0, %2
>>>
>>> ret i1 %3
>>>
>>> }
>>>
>>> On Friday, October 7, 2016 at 10:56:26 AM UTC-3, Kevin Liu wrote:
>>>>
>>>> Sorry, no need, I got this
>>>>
>>>> *julia> **@code_llvm(a<=b)*
>>>>
>>>>
>>>> define i1 @"julia_<=_21637"(i1, i1) {
>>>>
>>>> top:
>>>>
>>>> %2 = xor i1 %0, true
>>>>
>>>> %3 = or i1 %1, %2
>>>>
>>>> ret i1 %3
>>>>
>>>> }
>>>>
>>>>
>>>> *julia> **@code_llvm(ifelse(a,b,true))*
>>>>
>>>>
>>>> define i1 @julia_ifelse_21636(i1, i1, i1) {
>>>>
>>>> top:
>>>>
>>>> %3 = select i1 %0, i1 %1, i1 %2
>>>>
>>>> ret i1 %3
>>>>
>>>> }
>>>>
>>>>
>>>> How do you read this output?
>>>>
>>>> On Friday, October 7, 2016 at 10:50:57 AM UTC-3, Kevin Liu wrote:
>>>>>
>>>>> Jeffrey, can you show the expression you put inside @code_llvm() and
>>>>> @code_native() for evaluation?
>>>>>
>>>>> On Friday, October 7, 2016 at 2:26:56 AM UTC-3, Jeffrey Sarnoff wrote:
>>>>>>
>>>>>> Hi Jussi,
>>>>>>
>>>>>> Your version compiles down more neatly than the ifelse version. On my
>>>>>> system, BenchmarkTools gives nearly identical results; I don't know why,
>>>>>> but the ifelse version is consistently a smidge faster (~%2, relative
>>>>>> speed). Here is the llvm code and local native code for each, your
>>>>>> version
>>>>>> looks more tidy.
>>>>>>
>>>>>>
>>>>>> ```
>>>>>> implies(p::Bool, q::Bool) = (p <= q) implies(p::Bool,
>>>>>> q::Bool) = ifelse( p, q, true )
>>>>>>
>>>>>> # llvm
>>>>>>
>>>>>> %2 = xor i8 %0, 1 %2 = and i8 %0, 1
>>>>>> %3 = or i8 %2, %1 %3 = icmp eq i8
>>>>>> %2, 0
>>>>>> ret i8 %3 %4 = select i1 %3,
>>>>>> i8 1, i8 %1
>>>>>> ret i8 %3
>>>>>>
>>>>>> # native with some common code removed
>>>>>>
>>>>>> xorb $1, %dil testb $1, %dil
>>>>>> orb %sil, %dil movb $1, %al
>>>>>> movb %dil, %al je L15
>>>>>> popq %rbp movb %sil, %al
>>>>>> retq L15: popq %rbp
>>>>>> retq
>>>>>> ```
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Friday, October 7, 2016 at 12:22:23 AM UTC-4, Jussi Piitulainen
>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>> implies(p::Bool, q::Bool) = p <= q
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> torstai 6. lokakuuta 2016 19.10.51 UTC+3 Kevin Liu kirjoitti:
>>>>>>>>
>>>>>>>> How is an implication represented in Julia?
>>>>>>>>
>>>>>>>>
>>>>>>>> https://en.wikipedia.org/wiki/Material_conditional#Definitions_of_the_material_conditional
>>>>>>>>
>>>>>>>
