// pc == 0, to make unwinding show the context.
		if pc != 0 && !findfunc(pc).valid() && findfunc(*(*uintptr)(unsafe.Pointer(sp))).valid() {
			pc = 0
		}

		// IF LR exists, sigpanictramp must save it to the stack
		// before entry to sigpanic so that panics in leaf
		// functions are correctly handled. This will smash
		// the stack frame but we're not going back there
		// anyway.
		if usesLR {