GCC Purpose Guide agents through GCC invocation: flag selection, build modes, warning triage, PGO, LTO, and common error patterns. Assume the project uses GNU Make, CMake, or a shell script. Triggers - "What flags should I use for a release build?" - "GCC is giving me a warning/error I don't understand" - "How do I enable LTO / PGO with GCC?" - "How do I compile with ?" - "My binary is too large / too slow" - Undefined reference errors, ABI mismatch, missing symbols Workflow 1. Choose a build mode | Goal | Recommended flags | |------|-------------------| | Debug | | | Debug + debuggable optim…