Comment on Libgccjit.so: an embeddable JIT-compiler based on GCCparentComments−rayiner12yLLVM's instruction selection/legalization infrastructure is very sophisticated, very generic, table-driven, etc. Most JIT compilers use more ad-hoc and quicker mechanisms to get machine code out of IR.−foobarbazqux12yYeah okay. Someone else pointed out FastISel.cpp. It's probably true that prettiness competes with performance.−rayiner12yFastISel will quite often kick out to the regular instruction selector because it can't handle particular IR constructs.
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LLVM's instruction selection/legalization infrastructure is very sophisticated, very generic, table-driven, etc. Most JIT compilers use more ad-hoc and quicker mechanisms to get machine code out of IR.
Yeah okay. Someone else pointed out FastISel.cpp. It's probably true that prettiness competes with performance.
FastISel will quite often kick out to the regular instruction selector because it can't handle particular IR constructs.