Just as a quick note: This will make my Metal shader parser just a tad bit more annoying to do, as MSL wants you to write those operations explicitly so the compiler can optimise them itself.

So what would mad(u, 1. / 1.055, .055 / 1.055) be as a standard math expression?

(Supposedly x += m * a should result in the same byte code as x = mad(m,a,x) anyway, but that might not be the case in the specific instructions we use it in?)

We're already using mad in libobs so it's there even without this PR. I added gl_write_mad a while ago to gl-shaderparser.c since fma is not available in GLSL 330.
mad(a, b, c) -> ((a) * (b) + (c))
I use mad explicitly because I've seen at least one GPU driver fail to fuse the operations without the intrinsic.

We're already using mad in libobs so it's there even without this PR. I added gl_write_mad a while ago to gl-shaderparser.c since fma is not available in GLSL 330. mad(a, b, c) -> ((a) * (b) + (c)) I use mad explicitly because I've seen at least one GPU driver fail to fuse the operations without the intrinsic.

Got it, yeah I'm still torn on whether to simply polyfill HLSL functions in MSL instead of translating them - looks like I already implemented it but for 3 arguments at most:

https://github.com/PatTheMav/obs-studio/blob/e482e1a86250fad3ca85d407741a11949f719621/libobs-metal/OBSShaderParser.swift#L944