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This commit promotes "big" constants i.e. those in the constant pool. This is possible thanks to 60c3e59, but still requires some work: in particular, we have to create different codepaths to ensure that whenever we load something out of the constant pool we do so via an idempotent function. Fortunately, by introducing "K" variants of some macros, we can do this in a way that doesn't cause much code corruption. Speeds up cd/json/storage by ~2%.
vext01
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Mar 24, 2026
| NOOPT_VAL(o); | ||
| uint64_t x; | ||
| // FIXME: We currently have to use memcpy to bitcast from lua_Number to uint64_t | ||
| memcpy(&x, &o->value_.n, sizeof(lua_Number)); |
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llvm will probably eliminate the memcpy anyway.
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It becomes a bitcast (but this is an ugly, and obsucatory, way to have to do it! But there's nothing better in C AFAIK).
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This commit promotes "big" constants i.e. those in the constant pool. This is possible thanks to 60c3e59, but still requires some work: in particular, we have to create different codepaths to ensure that whenever we load something out of the constant pool we do so via an idempotent function. Fortunately, by introducing "K" variants of some macros, we can do this in a way that doesn't cause much code corruption. Speeds up cd/json/storage by ~2%.
@vext01 You'll notice I've had to hack around
idempotent_promotenot supporting floats/doubles here. It's not a big deal, but is a bit icky. It also makes me realise that if we hadyk_idempotent_promote(x)as a function we could do the same ABI "are we tracing" trick in a way that would remove a whole load of these idempotent_promote calls. Would it make much performance difference? Hard to say!