cmd/compile: panic: bad move #81976

$ gotip version
go version go1.28-devel_6f5c275ebdc Fri Oct 2 14:55:20 2026 -0700 linux/amd64

package p

import "simd/archsimd"

func F(z archsimd.Float32x8) archsimd.Float32x8 {
	_ = func() {
		fu := func(p1 int, p2 map[int]int) {}
		fu(func() int {
			z = z.Compress(archsimd.Mask32x8{})
			return z.Len()
		}(), map[int]int{})
		for range 2 {
			z = z.Expand(archsimd.Mask32x8{})
		}
	}
	return z
}

$ GOEXPERIMENT=simd gotip build crash.go 
# command-line-arguments
panic: bad move, src=2124, dest=2101, width=8 [recovered, repanicked]

goroutine 22 [running]:
sync.(*WaitGroup).Go.func1.1()
	../desktop/gotip/src/sync/waitgroup.go:251 +0x3e
panic({0x19b2fd0?, 0x312fc3dce600?})
	../desktop/gotip/src/runtime/panic.go:859 +0x11f
cmd/compile/internal/amd64.moveByRegsWidth(0x835, 0xc34e?, 0x8, 0xbe?)
	../desktop/gotip/src/cmd/compile/internal/amd64/ssa.go:164 +0x2e7
cmd/compile/internal/amd64.ssaGenValue(0x312fc3c77a40, 0x312fc3d69b40)
	../desktop/gotip/src/cmd/compile/internal/amd64/ssa.go:1372 +0x249c
cmd/compile/internal/ssagen.genssa({0x1a20078, 0x0}, 0x312fc3dd01c0, 0x312fc3de6900)
	../desktop/gotip/src/cmd/compile/internal/ssagen/ssa.go:7212 +0x18bf
cmd/compile/internal/ssagen.Compile({0x1a1d808, 0x1ccda20}, 0x312fc3c4a500, 0x3, 0x0?)
	../desktop/gotip/src/cmd/compile/internal/ssagen/pgen.go:316 +0x513
cmd/compile/internal/gc.compileFunctions.func2()
	../desktop/gotip/src/cmd/compile/internal/gc/compile.go:174 +0x1ab
sync.(*WaitGroup).Go.func1()
	../desktop/gotip/src/sync/waitgroup.go:258 +0x4a
created by sync.(*WaitGroup).Go in goroutine 1
	../desktop/gotip/src/sync/waitgroup.go:238 +0x7d