Optimizer Artifacts in Assembly

When to use

• Reading -O2/-O3 assembly produced from C/C++ and mapping it back to the source.
• Explaining why a function body "disappeared", a call became a jmp, or an imul became a lea.
• Checking whether generated code does what the source says (reviews, reverse engineering, ABI verification).
• Comparing -O0 vs -O2 disassembly to understand what the optimizer changed.

When not to use

• Deciding whether source contains UB — use c-undefined-behavior / compiler-ub-assumptions first; optimizer behavior caused by UB is that skill's domain.
• Writing inline asm — use asm-inline-asm-constraints.
• Reading debug info to recover source variables — use dwarf-debug-info.
• Anything ARM/AArch64/RISC-V — these artifacts are x86-64 examples; the concepts transfer but the instructions differ.

What the agent often gets wrong