> Wouldn't this prevent optimizations in cases like: > > insn 1: r1 = r2 + r3 > insn 2: r4 = r1, r1 dead > insn 3: unspec_volatile > > With the proposal above we would mark r1 with an invalid use when passing > insn 3. But for registers which are already dead we should not do this.
You're right. The patch is OK, thanks for explaining. -- Eric Botcazou
