In the early days of gcc (2.8 etc.) and in the times of egcs, and redhat 2.96 -O3 was quite buggy sometimes. But this is over a decade ago, and -O3 is not much different than other levels of optimizations (in buggyness). It does however tend to reveal cases where people rely on undefined behavior, … Read more
This did the job (in the year 2012): #include <stdio.h> const unsigned long long size = 8ULL*1024ULL*1024ULL; unsigned long long a[size]; int main() { FILE* pFile; pFile = fopen(“file.binary”, “wb”); for (unsigned long long j = 0; j < 1024; ++j){ //Some calculations to fill a[] fwrite(a, 1, size*sizeof(unsigned long long), pFile); } fclose(pFile); return … Read more
If I understand correctly, performance-wise, flipping the sign of Z and the depth test is nothing but changing a < comparison to a > comparison. So, if I understand correctly and the author isn’t lying or making things up, then changing < to > used to be a vital optimization for many games. I didn’t … Read more
It’s better to use either of the following: — Method 1. SELECT 1 FROM table_name WHERE unique_key = value; — Method 2. SELECT COUNT(1) FROM table_name WHERE unique_key = value; The first alternative should give you no result or one result, the second count should be zero or one. How old is the documentation you’re … Read more
Updated 4 June 2017 Given that this question/answer have gained some popularity, I figured it was worth an update. When this question was originally posted, MySQL had no support for JSON data types and the support in PostgreSQL was in its infancy. Since 5.7, MySQL now supports a JSON data type (in a binary storage … Read more
Finally in .NET 4.5, the CLR allows one to hint/suggest1 method inlining using MethodImplOptions.AggressiveInlining value. It is also available in the Mono’s trunk (committed today). // The full attribute usage is in mscorlib.dll, // so should not need to include extra references using System.Runtime.CompilerServices; … [MethodImpl(MethodImplOptions.AggressiveInlining)] void MyMethod(…) 1. Previously “force” was used here. I’ll … Read more
You don’t need and you should never write code like that – especially if you’re not a C compiler / standard library vendor. It is code used to implement strlen with some very questionable speed hacks and assumptions (that are not tested with assertions or mentioned in the comments): unsigned long is either 4 or … Read more
Ok, after some time, here’s what I landed on: .parent { position: relative; top: 0; left: 0; } .image1 { position: relative; top: 0; left: 0; border: 1px red solid; } .image2 { position: absolute; top: 30px; left: 30px; border: 1px green solid; } <div class=”parent”> <img class=”image1″ src=”https://via.placeholder.com/50″ /> <img class=”image2″ src=”https://via.placeholder.com/100″ /> </div> … Read more
There are two varieties of unused code: the local one, that is, in some functions some paths or variables are unused (or used but in no meaningful way, like written but never read) the global one: functions that are never called, global objects that are never accessed For the first kind, a good compiler can … Read more