target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128" target triple = "wasm32-unknown-unknown" ; This function, when compiled will generate a new undefined reference to ; memcpy, that is not present in the bitcode object define void @func_with_libcall(ptr %a, ptr %b) { entry: call void @llvm.memcpy.p0.p0.i64(ptr %a, ptr %b, i64 1024, i1 false) ret void } declare void @llvm.memcpy.p0.p0.i64(ptr nocapture, ptr nocapture, i64, i1)