asmArchPpc64    = asmArch{name: "ppc64", bigEndian: true, stack: "R1", lr: true, retRegs: []string{"R3", "F1"}}
	asmArchPpc64LE  = asmArch{name: "ppc64le", bigEndian: false, stack: "R1", lr: true, retRegs: []string{"R3", "F1"}}
	asmArchRISCV64  = asmArch{name: "riscv64", bigEndian: false, stack: "SP", lr: true, retRegs: []string{"X10", "F10"}}
	asmArchS390X    = asmArch{name: "s390x", bigEndian: true, stack: "R15", lr: true}

func (c *Client) Do(req *Request) (*Response, error) {
	return c.do(req)
}

var testHookClientDoResult func(retres *Response, reterr error)

func (c *Client) do(req *Request) (retres *Response, reterr error) {
	if testHookClientDoResult != nil {
		defer func() { testHookClientDoResult(retres, reterr) }()
	}
	if req.URL == nil {
		req.closeBody()
		return nil, &url.Error{
			Op:  urlErrorOp(req.Method),

			// and efficient method that combines multiple factors.
			idx := -1
			for i, p := range b.Preds {
				// If the predecessor has not been visited yet, skip it because its end state
				// (redRegs and spillLive) has not been computed yet.
				pb := p.b
				if s.blockOrder[pb.ID] >= s.blockOrder[b.ID] {
					continue
				}
				if idx == -1 {
					idx = i
					continue
				}