Thursday, November 11, 2010

Question 20.15b

comp.lang.c FAQ list · Question 20.15b

Q: People claim that optimizing compilers are good and that we no longer have to write things in assembler for speed, but my compiler can't even replace i/=2with a shift.


A: Was i signed or unsigned? If it was signed, a shift is not equivalent (hint: think about the result if i is negative and odd), so the compiler was correct not to use it.

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