常量折叠(constant folding) 是 Python 中的一种窥孔优化(peephole optimization)技术. 这意味着在编译时表达式'a'*20会被替换为'aaaaaaaaaaaaaaaaaaaa'以减少运行时的时钟周期. 只有长度小于 20 的字符串才会发生常量折叠. (为啥? 想象一下由于表达式'a'*10**10而生成的.pyc文件的大小). 相关的源码实现在这里...
常量折叠(constant folding) 是 Python 中的一种 窥孔优化(peephole optimization) 技术. 这意味着在编译时表达式 'a'*20 会被替换为 'aaaaaaaaaaaaaaaaaaaa' 以减少运行时的时钟周期. 只有长度小于 20 的字符串才会发生常量折叠. (为啥? 想象一下由于表达式 'a'*10**10 而生成的 .pyc 文件的大小). 相关...
对象(因为"wtf!"不是按照上面提到的方式被隐式驻留的)。 常量折叠(constant folding)是 Python 中的一种窥孔优化(peephole optimization)技术。这意味着在编译时表达式'a' * 20会被替换为'aaaaaaaaaaaaaaaaaaaa'以减少运行时的时钟周期。只有长度小于 20 的字符串才会发生常量折叠。(为啥?想象一下由于表达式'a' ...
常量折叠是Python实现的一种窥孔优化(Peephole optimization)技术。意思就是'a'*20这个语句在编译的时候会自动替换成'aaaaaaaaaaaaaaaaaaaa'这个变量,用来减少运行时的运算时钟周期('a'*20需要多执行20次乘法运算)。常量折叠只在字符串长度小于等于20的时候发生(至于为什么?想想如果有一个'a*10**10'这样的语句,折...
The abrupt change in the output of the fourth snippet is due to a peephole optimization technique known as Constant folding. This means the expression 'a'*20 is replaced by 'aaaaaaaaaaaaaaaaaaaa' during compilation to save a few clock cycles during runtime. Constant folding only occurs for ...
常量折叠(constant folding) 是 Python 中的一种 窥孔优化(peephole optimization) 技术. 这意味着在编译时表达式 'a'*20 会被替换为 'aaaaaaaaaaaaaaaaaaaa' 以减少运行时的时钟周期. 只有长度小于 20 的字符串才会发生常量折叠. (为啥? 想象一下由于表达式 'a'*10**10 而生成的 .pyc 文件的大小). 相关...
Constant folding has been moved from the peephole optimizer to the new AST optimizer, which is able perform optimizations more consistently. (Contributed by Eugene Toder and INADA Naoki in bpo-29469 and bpo-11549.) Most functions and methods in abc have been rewritten in C. This makes creatio...
SSA-based idioms optimization phase Performs classic "peephole" optimizations. Priority Order Register Allocation Assigns registers to operands. X87 Stack Allocation Allocates the x87 stack. GS Security Cookie Initialization and Check Implements the /GS option (stack security). Native EH Lower Expresses...
SSA-based idioms optimization phase Performs classic "peephole" optimizations. Priority Order Register Allocation Assigns registers to operands. X87 Stack Allocation Allocates the x87 stack. GS Security Cookie Initialization and Check Implements the /GS option (stack security). Native EH Lower Expresses...
SSA-based idioms optimization phase Performs classic "peephole" optimizations. Priority Order Register Allocation Assigns registers to operands. X87 Stack Allocation Allocates the x87 stack. GS Security Cookie Initialization and Check Implements the /GS option (stack security). Native EH Lower Expresses...