I can repro with 1.20rc3. Same error.

Weird, this is basically an assembler failure. It would really help to get a reproducer.

@golang/arm

@randall77 I can e-mail you the code if you'd like. Or I believe I can invite you to the repo. It's not secret, we just haven't decided on a license yet.

There is no hurry. If it's going to be available soon (before May 1, say) then we can wait. If not, then try to get a standalone reproducer. Even if we could look at private code, it makes it hard to, e.g., write a test case that we can submit into the public repo.

In any case, I don't think I'm the one to look at this. I don't know much about the arm assembler.

It looks to me that this switch https://cs.opensource.google/go/go/+/master:src/cmd/internal/obj/arm/asm5.go;l=691 may miss a case for HAUTO (and a few others). I'll send a CL for you to try. A reproducer may still be good. Thanks.

Change https://go.dev/cl/463138 mentions this issue: cmd/internal/obj/arm: handle HAUTO etc. in addpool

@elagergren-spideroak could you try if CL https://golang.org/cl/463138 helps? (You'll need to build the Go toolchain with that patch applied.) Thanks.

@cherrymui yup, that fixes it! Tested with go version devel go1.21-99d8ecd997 Mon Jan 23 13:33:04 2023 -0500 linux/arm (gotip download 463138).

@elagergren-spideroak could you share a more complete repro so we can have a test case? Thanks.

@cherrymui I am working on a minimal repro. It might not be perfectly minimal, though. Sorry in advance.

@cherrymui okay, it's pretty minimal:

package main

func main() {
	Decode[int16](nil)
	Decode[uint16](nil)
	Decode[float64](nil)
}

func DecodeInt16(b []byte) (int16, int) {
	return 0, 0
}

func DecodeUint16(b []byte) (uint16, int) {
	return 0, 0
}

func DecodeFloat64(b []byte) (float64, int) {
	return 0, 0
}

func Decode[T any](b []byte) (T, int) {
	switch any(*new(T)).(type) {
	case int16:
		v, n := DecodeInt16(b)
		return any(v).(T), n
	case uint16:
		v, n := DecodeUint16(b)
		return any(v).(T), n
	case float64:
		v, n := DecodeFloat64(b)
		return any(v).(T), n
	default:
		panic("")
	}
}

$ go version
go version go1.19.1 linux/arm
$ go run main.go
# command-line-arguments
./main.go:33:8: illegal combination 00344 (/tmp/main.go:21)	WORD	main..autotmp_25-2(SP); NONE NONE HAUTO; from 0 0; to 3 3
$ go1.19.3 run main.go
# command-line-arguments
./main.go:33:8: illegal combination 00344 (/tmp/main.go:21)	WORD	main..autotmp_25-2(SP); NONE NONE HAUTO; from 0 0; to 3 3

Thanks. Added to the CL.