C++ inlining of references (original) (raw)

Thomas Schatzl thomas.schatzl at oracle.com
Tue Mar 21 09:36:24 UTC 2017

Hi Ioi,

On Tue, 2017-03-21 at 17:25 +0800, Ioi Lam wrote:

How good are C++ compilers with optimizing references in inline  functions? I have 2 functions that have a large common header:

foo() {  int x = xxx();  int y = yyy();  dofoo(x, y); } bar() {  int x = xxx();  int y = yyy();  dobar(x, y); } So I want to refactor it to inline void common(int&x, int &y) {  x = xxx();  y = yyy(); } foo() {  int x, y;  common(x, y);  dofoo(x, y); } bar() {  int x, y;  common(x, y);  dobar(x, y); } Because the common header modifies 2 variables, there's no easy way to pass them back easily. So I pass them as references to the inline function. Can I expect modern C++ compilers to always generate equally optimal  code for the before/after cases?

  try it yourselves: https://godbolt.org/ :)

Thanks,   Thomas

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