The pattern "Code composition - expensive instructions" can be used to describe what happens if you use expensive instructions although there are cheaper ways.
Like Instruction Overhead.
For a piece of high-level code, the compiler outputs a lot of instructions although is could be done in less. One common example are non-vectorized instructions.
High CPI if the problem is large-latency arithmetic
Possible optimizations and/or fixes
Reduce complexity to that the compiler can generate better code