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Re:Make LLVM Fast Again by 1980phipsi on Monday May 11, 2020 @06:28AM (#23140637)
Does clang have -O0?
Re:Make LLVM Fast Again by GuB-42 on Monday May 11, 2020 @06:37AM (#23140682)
Yes (clang11 documentation)

  -O0, -O1, -O2, -O3, -Ofast, -Os, -Oz, -Og, -O, -O4
      Specify which optimization level to use:
          -O0 Means “no optimization”: this level compiles the fastest and generates the most debuggable code.
          -O1 Somewhere between -O0 and -O2.
          -O2 Moderate level of optimization which enables most optimizations.
          -O3 Like -O2, except that it enables optimizations that take longer to perform or that may generate larger code (in an attempt to make the program run faster).
          -Ofast Enables all the optimizations from -O3 along with other aggressive optimizations that may violate strict compliance with language standards.
          -Os Like -O2 with extra optimizations to reduce code size.
          -Oz Like -Os (and thus -O2), but reduces code size further.
          -Og Like -O1. In future versions, this option might disable different optimizations in order to improve debuggability.
          -O Equivalent to -O2.
          -O4 and higher
              Currently equivalent to -O3