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Frequently Asked Question

Illegal Instruction on MacOS X


You've downloaded the binary distribution of Yices for MacOS X. When you try to use yices, it breaks with the following error: Illegal Instruction: 4


We build the binary distribution on a Mac that supports Intel's AVX2 instructions. Some older Intel CPUs do not support these instructions, and our pre-compiled binaries will not work on these CPUs.

You can check whether you CPU and OS support AVX2 by opening a terminal and typing

sysctl -a | grep hw

If AVX2 is supported, you'll see:

hw.optional.avx2_0: 1

Otherwise, you'll see:

hw.optional.avx2_0: 0


If your CPU does not support AVX2, you have to install Yices from the source. The simplest method is to use brew:

brew install SRI-CSL/sri-csl/yices2

You can also download the Source Code or clone our GitHub repository, then follow these instructions.

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