julia

d6dd59ba - Reduce branches in 2x2 and 3x3 stable_muladdmul for standard cases (#54951)

Reduce branches in 2x2 and 3x3 stable_muladdmul for standard cases (#54951) We may use the knowledge that `alpha != 0` at the call site to hard-code `alpha = true` in the `MulAddMul` constructor if `alpha isa Bool`. This eliminates the `!isone(alpha)` branches in `@stable_muladdmul`, and reduces latency in matrix multiplication. ```julia julia> using LinearAlgebra julia> A = rand(2,2); julia> @time A * A; 0.596825 seconds (1.05 M allocations: 53.458 MiB, 5.94% gc time, 99.95% compilation time) # nightly v"1.12.0-DEV.789" 0.473140 seconds (793.52 k allocations: 39.946 MiB, 3.28% gc time, 99.93% compilation time) # this PR ``` In a separate session, ```julia julia> @time A * Symmetric(A); 0.829252 seconds (2.37 M allocations: 120.051 MiB, 1.98% gc time, 99.98% compilation time) # nightly v"1.12.0-DEV.789" 0.712953 seconds (2.06 M allocations: 103.951 MiB, 2.17% gc time, 99.98% compilation time) # This PR ```