What Is Profile-Guided Optimization?
Profile-guided optimization is a technique where a program is first run on representative workloads to collect data on which branches, calls, and paths are common, and that profile is then given to the compiler for a second build. The compiler uses it to make better decisions about inlining, branch layout, and hot-path placement. The result is code tuned to real usage rather than static heuristics.
Why it matters
Knowing which paths are actually hot lets the compiler lay out and inline code for the common case, often beating guesswork-based optimization. The cost is a more involved, two-pass build process with a representative profiling run.
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