I feel like I’m kinda being the bad aunt by encouraging -ffast-math. It can definitely break some things (i.e. https://pspdfkit.com/blog/2021/understanding-fast-math/ ) but I use it habitually and I’m fine so clearly it’s safe.
I recall it totally fudged up the ray-axis aligned bounding box intersection routine in the raytracer I worked on. The routine relied on infinities being handled correctly, and -ffast-math broke that.
I see the linked article goes into that aspect in detail, wish I had it back then.
IIRC we ended up disabling it for just that file, as it did speed up the rest my a fair bit.
can confirm fast math makes the biggest difference
I feel like I’m kinda being the bad aunt by encouraging -ffast-math. It can definitely break some things (i.e. https://pspdfkit.com/blog/2021/understanding-fast-math/ ) but I use it habitually and I’m fine so clearly it’s safe.
> It can definitely break some things
I recall it totally fudged up the ray-axis aligned bounding box intersection routine in the raytracer I worked on. The routine relied on infinities being handled correctly, and -ffast-math broke that.
I see the linked article goes into that aspect in detail, wish I had it back then.
IIRC we ended up disabling it for just that file, as it did speed up the rest my a fair bit.
Fast Math basically means "who cares about standards just add in whatever order you want" :)