ALUs[1] do not really consume that large of an area of a CPU so just sharing those is a significant complication with little benefits. Sharing register files, c

ALUs[1] do not really consume that large of an area of a CPU so just sharing those is a significant complication with little benefits. Sharing register files, caches, store buffers, ROBs, TLBs, prediction tables, and the logic to drive them is a better trade-off. [1] outside of large SIMD FPUs, which indeed bulldozer tried to share with not great results.