search for: llvm_gcwrite

...etermined, for an operation, to implement it as an opcode or as an intrinsic function? As I understand it, compilation passes can both lower intrinsics into opcodes and also replace opcode sequences, so in the end some of them are interchangeable. For example, why is there a store opcode and a llvm_gcwrite intrinsic? Couldn't the front-end just produce stores/volatile stores and then a compilation pass transform them into a write-barrier if necessary? A possible view of intrinsics could be "operations that don't depend on the target architecture, but instead on the language runtime&q...

...y intrinsic can be lowered onto an explicit LLVM loop, but the memcpy intrinsic provides a succinct representation of memory copy and so stays as such. Plus, it is harder to do the reverse analysis -- prove that a loop is essentially a memcpy(). > For example, why is there a store opcode and a llvm_gcwrite intrinsic? The 'store' opcode is for generic writes, the gcwrite is specifically for garbage collection. I think someone else would be able to give you more information about the GC intrinsics than I am, however. > Couldn't the front-end just produce stores/volatile stores and the...

...ecode encoding: instructions are encoded more densely than intrinsics. > As I understand it, compilation passes can both lower intrinsics into > opcodes and also replace opcode sequences, so in the end some of them > are interchangeable. For example, why is there a store opcode and a > llvm_gcwrite intrinsic? As pointed out by others, these are completely different operations. In particular, the gcwrite intrinsic is used by the front-end to indicate that a write-barrier may be needed. Depending on the implementation of the garbage collector, this may expand to code or just a normal store i...