[Build] Add LTO, PGO, and -march=native CMake options#11025
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taherbert wants to merge 1 commit intosimulationcraft:midnightfrom
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[Build] Add LTO, PGO, and -march=native CMake options#11025taherbert wants to merge 1 commit intosimulationcraft:midnightfrom
taherbert wants to merge 1 commit intosimulationcraft:midnightfrom
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The legacy engine/Makefile supports LTO, PGO, and -march=native but the CMake build has no equivalent. This adds opt-in CMake options that bring those capabilities to cmake users. New options (all OFF by default, existing builds unaffected): - SC_LTO: thin LTO on Clang, full LTO on GCC - SC_MARCH_NATIVE: tune for the host CPU - SC_PGO_GENERATE / SC_PGO_USE: LLVM/GCC profile-guided optimization Bumps cmake_minimum_required to 3.13 for target_link_options(). Also adds scripts/benchmark.sh which automates a three-way comparison (baseline vs LTO+march vs PGO+LTO+march) and prints a results table. Tested on Apple Silicon (M4 Max, AppleClang 17): Variant Time(s) Speedup Release (baseline) 0.64 1.00x LTO + march=native 0.57 1.12x PGO + LTO + march=native 0.55 1.16x (best of 3 runs, 1000 iterations, 4 threads, MID1_Priest_Shadow)
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The legacy engine/Makefile supports LTO, PGO, and -march=native but the CMake build has no equivalent. This adds them as opt-in options.
New options (all OFF by default — existing builds unaffected):
SC_LTO— thin LTO on Clang, full LTO on GCCSC_MARCH_NATIVE— tune for the host CPUSC_PGO_GENERATE/SC_PGO_USE— profile-guided optimization (Clang and GCC)Bumps
cmake_minimum_requiredto 3.13 fortarget_link_options().Also adds
scripts/benchmark.shwhich builds all three variants and prints a comparison table.Results (Apple Silicon M4 Max, AppleClang 17, best of 3 runs, 1000 iterations, 4 threads):
-ffast-mathwas also tested — it made things 3x slower, so it is excluded.Usage:
Or run
scripts/benchmark.shfor the full comparison including PGO.Note: Let me know if we'd prefer to remove benchmarking script, but thought it would be helpful for verification.