Advertisements I stumbled across this Reddit post which is a joke on the following code snippet, void f(int& x) { if (x != 1) { x = 1; } } void g(int& x) { x = 1; } saying that the two functions are not equivalent to ‘the compiler’. I was convinced that any of… Read More Why do none of the major compilers optimize this conditional move?

Advertisements I have the following sample code: inline float successor(float f, bool const check) { const unsigned long int mask = 0x7f800000U; unsigned long int i = *(unsigned long int*)&f; if (check) { if ((i & mask) == mask) return f; } i++; return *(float*)&i; } float next1(float a) { return successor(a, true); } float… Read More Clang 14 and 15 apparently optimizing away code that compiles as expected under Clang 13, ICC, GCC, MSVC

Advertisements I have a question about the python compiler. I was running the below code but I got some errors that weren’t logical. if you run a python code and then add the exit() function to it, it would exit the program and the following codes wouldn’t run. but I added the exit() function to… Read More why python compiler doesn't ignore syntax errors after exit()?

Advertisements Suppose I have the following C line: int a = 4 + 7; When compiling this line, GCC will always produce something like mov DWORD PTR [rbp-X], 0xb, as the result of this computation is constant and known at compile time. Is there a way to disable this behaviour to have a mov 4,… Read More Disable GCC simplification of expressions known at compile time