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Parallel, speculative execution is what's unavoidable. The VLIW idea of statically compiler-scheduled parallelism and speculation has not been successful for general-purpose code. The last generation of Itanium abandoned explicit, statically-scheduled parallelism and switched to out of order execution, like every fast general-purpose CPU uses.

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> has not been successful for general-purpose code

Let me interject that it has also not been successful for AMD's line of videocards - they used a VLIW architecture before transitioning to a SIMD architecture codenamed Graphics Core Next or GCN in 2011. nVidia had been using SIMD for quite a while before that, but some of their latest cards have a few VLIW features like the option to explicitly specify parallelism between instructions.

Apparently they switched because VLIW wasn't good for GPGPU workloads, which is in keeping with the general theme, that VLIW works very well on certain highly-specific DSP-ish workloads.

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