[nwallin]

My feeling about JavaScript is statistically speaking, random JavaScript code is more likely to be spaghetti nonsense than, say, the equivalent Python code. This feeling isn't based on empirical data, tbh it's probably as much anti-JS bias as it is experience with poorly written JavaScript.

Is your criticism of tracing specific to messy, confusing code, with lots of edge cases in the main loop, or does it also hold true for well written code?

I have no experience with compiler design, didn't even take a compilers course in college.

[foobazgt]

Nah, as titzer said, it's really about general-purpose code being branchy (a good match for CPUs) vs numeric code being heavily parallelized and non-branchy (a good match for SIMD/GPUs). Only a small subset of very specific languages / instructions target the latter (e.g. CUDA and SSE4).