matt godbolt @mattgodbolt@hachyderm.io
Public

Day 21 of Advent of Compiler Optimisations!

Summing an array of integers? The compiler vectorises it beautifully, processing 8 at a time with SIMD. Switch to floats and... the compiler refuses to vectorise, doing each add one by one. Same loop, same code structure — why does the compiler treat floats so differently?

Read more: xania.org/202512/21-vectorisin
Watch: youtu.be/lUTvi_96-D8

When SIMD Fails: Floating Point Associativity — Matt Godbolt’s blog

Why floating point maths doesn't vectorise like integers, and what to do about it

xania.org

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