We are working on proving the execution of go-compiled WASM code using zero-knowledge (ZK) (see https://github.com/DelphinusLab/zkWasm). However, the current zkWASM prover cannot support floating point instructions (f32.xxx/f64.xxx). We tried to use go build -gcflags=all=-d=softfloat and we found most of the FP instructions are translated to INT ones except f64.load, f64.store, f64.ceil, f64.floor.

Q: Is there a way to support softfloat explicitly for WASM or any flags to fully support softfloat?

Test code (fp.go):

import "math"

func main() {
	a := 3.5
	b := 2.7
	println(math.Ceil(a))
	println(math.Floor(a))
	println(a / b)
}

Commands

$ go version
go version go1.21.0 linux/amd64
$ GOOS=js GOARCH=wasm go build -gcflags=all=-d=softfloat fp.go
$ wasm2wat fp | grep 'f32\.'
$ wasm2wat fp | grep 'f64\.'
    f64.load offset=8
    f64.floor
    f64.store offset=16
    f64.load offset=8
    f64.ceil
    f64.store offset=16