2015-11-19 22:29 GMT+01:00 stepharo <[email protected]>:
> SSA form?
>
>
and for method arguments?
foo: count
| sum |
sum := 0.
1 to: count do: [ :ku | sum := sum + ku ].
^ sum
transforms to:
"foo: arg1
| tmp1 tmp2 |
tmp1 := 0.
tmp2 := arg1.
1 to: tmp2 do: [ :tmp3 | tmp1 := tmp1 + tmp3 ].
^ tmp1"
> Le 19/11/15 22:14, Nicolai Hess a écrit :
>
> What is the purpose of replacing expressions, used as limits in a
>> to:do: call with by a new temporary variable?
>>
>> For example:
>>
>> OCOpalExamples>>#exampleToDoArgumentLimitIsExpression
>> the code is
>>
>> exampleToDoArgumentLimitIsExpression
>> | count sum |
>> count := 10.
>> sum := 0.
>> 1 to: count - 1 do: [ :each | sum := sum + each].
>> ^sum
>>
>> the decompiled bytecode :
>>
>> exampleToDoArgumentLimitIsExpression
>> | tmp1 tmp2 tmp3 |
>> tmp1 := 10.
>> tmp2 := 0.
>> tmp3 := tmp1 - 1.
>> 1 to: tmp3 do: [ :tmp4 | tmp2 := tmp2 + tmp4 ].
>> ^ tmp2
>>
>> So, the expression (count - 1) in the to:do: loop is replaced by a new
>> temporay (tmp3).
>>
>> Ok, but why ?
>>
>
>
>
