[llvm-profdata] Move error handling logic out of normal input's code path #67177
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…path Based on disassembly and profiling results, it looks like the cost of std::error_code and llvm::ErrorOr<> are non-trivial, as it involves virtual function calls that are not optimized in -O3. This patch moves error handling logic into the conditional branch in error checking, only generates std::error_code on actual error instead of the default case to generate sampleprof_error::success. In the next patch I am looking to change the API to uses a plain old enum for error checking instead, because based on profiling results error handling related code accounts for 7-8% of the profile loading time even if there's no error at all.
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Based on disassembly and profiling results, it looks like the cost of std::error_code and llvm::ErrorOr<> are non-trivial, as it involves virtual function calls that are not optimized in -O3.
This patch moves error handling logic into the conditional branch in error checking, only generates std::error_code on actual error instead of the default case to generate sampleprof_error::success.
In the next patch I am looking to change the API to uses a plain old enum for error checking instead, because based on profiling results error handling related code accounts for 7-8% of the profile loading time even if there's no error at all.