[Bug middle-end/97738] Optimizing division by value & - value for HAKMEM 175

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97738

--- Comment #2 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
Created attachment 49516
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49516&action=edit
Small benchmark

Here's a small benchmark for counting all 32-bit numbers with 16 bits set
according to the HAKMEM source.

Timing is (first float is elapsed time in seconds for version with division,
second float is for the shift):

2.319526 601080391
1.147284 601080391

with -O3 -march=native on an AMD Ryzen 7 1700X,

4.539288 601080391
2.700514 601080391

on POWER9.