[All] Using code lower scope micro-optimization #1877
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In the case C++ compilers, it is better to reduce scope visibility as little as possible for better branching code generation, strict indication scope optimizes code guaranteed on all compilers.
Reference: https://stackoverflow.com/questions/26333583/c-c-compiler-optimization-regarding-variable-scope
Example:
clang-19 -O2 lower scope variables (3 pcs move instr)
clang-19 -O2 without PR changes (much more instr and CPU clock cycles)