Illegal Instruction crash on CPUs without AVX since v2.1.113

Description

Starting from version 2.1.113, claude crashes immediately with Illegal instruction (core dumped) on CPUs that lack AVX support. Versions up to 2.1.112 work correctly.

Steps to Reproduce

1. Install Claude Code >= 2.1.113 on a system with a CPU without AVX instructions
2. Run claude --version
3. Observe: Illegal instruction (core dumped)

Binary Search Results

| Version | Status |
|---------|--------|
| 2.1.112 | ✅ works |
| 2.1.113 | ❌ crash |
| 2.1.114 | ❌ crash |
| 2.1.116 | ❌ crash |
| 2.1.120 | ❌ crash |
| 2.1.156 (latest) | ❌ crash |

The regression was introduced in 2.1.113.

Environment

• CPU: AMD Phenom II X4 955 (no AVX, no AVX2, no SSE4.2)
• OS: Linux Mint 22.2
• Kernel: 6.17.0-29-generic
• Node.js: v22.22.0
• Arch: x86_64

Expected Behavior

Claude Code should work on x86_64 CPUs without AVX instruction set, or at minimum provide a clear error message instead of crashing.

Workaround

Pin to the last working version:

npm install -g @anthropic-ai/claude-code@2.1.112