Skip to content

Extend LLVM 18 workaround to other float types. #3016

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
maleadt wants to merge 1 commit into
base: master
Choose a base branch
from
+7 −3
Open

Extend LLVM 18 workaround to other float types. #3016

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 7 additions & 3 deletions src/device/intrinsics/math.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -365,9 +365,13 @@ end
@static if Base.thismajor(LLVM.version()) <= v"18"
# LLVM 18 and below generate non-existing instructions for Julia's default methods of
# fast min/max on fp64: https://github.com/JuliaGPU/CUDA.jl/issues/2886
@device_override @inline Base.FastMath.max_fast(x::Float64, y::Float64) = ifelse(y > x, y, x)
@device_override @inline Base.FastMath.min_fast(x::Float64, y::Float64) = ifelse(y > x, x, y)
@device_override @inline Base.FastMath.minmax_fast(x::Float64, y::Float64) = ifelse(y > x, (x, y), (y, x))
for T in (Float16, Float32, Float64)
@eval begin
@device_override @inline Base.FastMath.max_fast(x::$T, y::$T) = ifelse(y > x, y, x)
@device_override @inline Base.FastMath.min_fast(x::$T, y::$T) = ifelse(y > x, x, y)
@device_override @inline Base.FastMath.minmax_fast(x::$T, y::$T) = ifelse(y > x, (x, y), (y, x))
end
Comment on lines +369 to +373
Copy link
Contributor

@giordano giordano Jan 12, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Can you do something like

@device_override @inline Base.FastMath.max_fast(x::$T, y::$T) where {T<:Union{Float16, Float32, Float64}} = ifelse(y > x, y, x)

just to avoid the loop
?

Copy link
Member Author

@maleadt maleadt Jan 12, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm always wary for doing so, because the Base method may then end up being more specific (and we really want these to apply). In this case, Base doesn't use metaprogramming so I guess it could work..

end
end

@device_function saturate(x::Float32) = ccall("extern __nv_saturatef", llvmcall, Cfloat, (Cfloat,), x)
Expand Down