search for: add_delta_256

...in a past life, when I used to do x86 SIMD optimization for a living, I did similar tricks pretty much everywhere in DSP functions. It’d be pretty nice if the compiler could do it too. There is one alternate approach that I recall, which looks like this: Original code (example, pseudocode): int add_delta_256(uint8 *in1, uint8 *in2) { int accum = 0; for (int i = 0; i < 16; ++i) { uint8x16 a = load16(in1 + i *16); // NOTE: takes an extra addressing op because x86 uint8x16 b = load16(in2 + i *16); // NOTE: takes an extra addressing op because x86 accum += psadbw(a, b); } return accum;...

I am attempting to implement a minor loop strength reduction optimization for targets that support compare and jump fusion, specifically TTI::canMacroFuseCmp(). My approach might be wrong; however, I am soliciting the idea for feedback, so that I can implement this correctly. My plan is to add a Supplemental LSR formula to LoopStrengthReduce.cpp that optimizes the following case, but perhaps