Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add mohitmishra786/low-level-dev-skills --skill compiler-optimizations-deepgit clone --depth 1 https://github.com/mohitmishra786/low-level-dev-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/mohitmishra786/low-level-dev-skills/compiler-optimizations-deep)<a href="https://agentmods.dev/skills/mohitmishra786/low-level-dev-skills/compiler-optimizations-deep"><img src="https://agentmods.dev/badge/skills/mohitmishra786/low-level-dev-skills/compiler-optimizations-deep.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00074 | $0.00872 |
| Opus 5 | $0.00037 | $0.00436 |
| Sonnet 5 | $0.00015 | $0.00174 |
| Haiku 4.5 | $0.00007 | $0.00087 |
Grade A, and why
compiler-optimizations-deep scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Compiler Optimizations (Deep)
Purpose
Explain optimization phases beyond flags: mid-level IR opts, register allocation, instruction selection/scheduling, vectorization boundaries, PGO, and post-link BOLT — bridging skills/compilers/pgo and LLVM/GCC internals.
When to Use
-O3did not vectorize a hot loop- Teaching why register pressure causes spills
- Planning PGO or BOLT deployment
- Understanding pass interaction (e.g., LICM before vectorize)
Workflow
1. Compiler pipeline map
Frontend → LLVM IR / GCC GIMPLE
├── Mid-level: DCE, GVN, LICM, inlining
├── Loop opts: unroll, vectorize
├── Codegen prep: legalize types
├── Instruction selection (DAG → machine ops)
├── Register allocation (greedy, linear scan)
└── Peephole / scheduling
2. Vectorization failure triage
clang -O3 -Rpass=loop-vectorize -Rpass-missed=loop-vectorize foo.c
| Miss reason | Typical fix |
|---|---|
| Unknown trip count | peel loop; assert count |
| Dependence | reorder / separate accumulators |
| Function call in loop | inline or outline |
| Alignment unknown | __builtin_assume_aligned |
3. Register allocation intuition
When live ranges exceed physical registers, the allocator spills to stack slots — costly loads/stores. Reducing live ranges (splitting variables, rematerialization) helps.
GCC/LLVM both use graph coloring variants (LLVM "greedy regalloc").
4. PGO workflow (Clang)
clang -fprofile-instr-generate -O2 -o app foo.c
./app # training workload
llvm-profdata merge default.profraw -o default.profdata
clang -fprofile-instr-use=default.profdata -O2 -o app_pgo foo.c
Improves branch layout, inlining, and vectorization thresholds.
See skills/compilers/pgo for GCC and BOLT.
5. BOLT (post-link)
llvm-bolt -instrument app -o app.inst
./app.inst
llvm-bolt -data=perf.fdata -reorder-blocks=+ -o app.bolt app
Optimizes layout after linker — needs relocations (-Wl,--emit-relocs).
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 9d ago First seen · 101 lines · 74 tokens per session scan A b2c8d0f07cb3
compiler-optimizations-deep is a skill published in the GitHub repository mohitmishra786/low-level-dev-skills (196 stars, last pushed 2mo ago), licensed MIT. It adds 74 tokens to every session and 872 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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