llvmllvm-irllc

llc throws error: constexpr requires integer operands

I've been experimenting with code generation with llvm. I'm currently trying to generate IR for variable declarations. Here is an example:

let sum: float = 8 * 3 * 4 + 6 * 9;

When I generate the IR for this, this is what I get:

  %sum = alloca float
  %sum1 = alloca float
  %sum2 = alloca float
  store float mul (float 8.000000e+00, float 3.000000e+00), float* %sum2
  %sum3 = load float, float* %sum2
  %sum4 = alloca float
  %sum5 = mul float %sum3, 4.000000e+00
  store float %sum5, float* %sum4
  %sum6 = load float, float* %sum4
  store float %sum6, float* %sum
  %sum_loaded = load float, float* %sum
  %sum7 = alloca float
  %sum8 = alloca float
  store float mul (float 6.000000e+00, float 9.000000e+00), float* %sum8
  %sum9 = load float, float* %sum8
  store float %sum9, float* %sum
  %sum_loaded10 = load float, float* %sum

Firstly, this looks quite messy, and I'm sure this can be done more efficiently. But i think i can fix it with optimizations later. My problem, is in testing to see if it works. I tried:

llc my_ir

Which throws:

llc: error: llc: my_ir:4:15: error: constexpr requires integer operands
  store float mul (float 8.000000e+00, float 3.000000e+00), float* %sum2

I don't really understand this error message, but it sounds like it can't multiply floats? What's going on here?

Solution

  • I think it's just that you need to use fmul to multiply floats.