@asmcall should use llvmcall ABI

[maleadt]

MWE:

using LLVM
using LLVM.Interop

function search(v, key)
    low = 0
    high = length(v)

    @inbounds while low ≤ high
        mid = round((high + low)÷2)
        middle = v[mid]
        if middle == key; return(mid); end
        new_low = mid
        new_high = mid

        low, high =
            @asmcall("""cmp \$4, \$5;
                        cmovae \$2, \$0;
                        cmovb \$3, \$1;""",
                "=r,=r,r,r,r,r,0,1",
                Tuple{Int,Int},
                Tuple{Int,Int,Int,Int,Int,Int},
                low, high, new_low, new_high, middle, key)
    end
end

ERROR: Failed to parse LLVM assembly:
<string>:7:23: error: number of output constraints does not match number of return struct elements
  %6 = call [2 x i64] asm "cmp $4, $5;\0Acmovae $2, $0;\0Acmovb $3, $1;", "=r,=r,r,r,r,r,0,1"(i64 %0, i64 %1, i64 %2, i64 %3, i64 %4, i64 %5)

Note the [2 x i64] in there; LLVM expects { i64, i64 }, so we should be able to invoke julia_type_to_llvm with llvmcall=true (this is currently not exported).

[maleadt]

The workaround here is to split the @asmcalls:

using LLVM
using LLVM.Interop

function search(v, key)
    low = 0
    high = length(v)

    @inbounds while low ≤ high
        mid = (high + low)÷2
        middle = v[mid]
        if middle == key
            return(mid)
        end
        new_low = mid
        new_high = mid

        low = @asmcall("cmp \$2, \$3; cmovae \$1, \$0;", "=r,r,r,r,0",
                       Int, Tuple{Int,Int,Int,Int}, low, new_low, middle, key)
        high = @asmcall("cmp \$2, \$3; cmovb \$1, \$0;", "=r,r,r,r,0",
                        Int, Tuple{Int,Int,Int,Int}, high, new_high, middle, key)

    end
end