2014-09-24 16:47 GMT+04:00 Steven Bosscher <stevenb....@gmail.com>: > On Wed, Sep 24, 2014 at 2:30 PM, Ilya Enkovich wrote: >> I didn't generate references separately from label. Now I found an >> old patch and a test where this problem appeared. In this patch I >> moved set_rip generation currently performed in ix86_expand_prologue >> into expand pass. And I got following code in expand dump for >> testsuite/gcc.target/i386/pr55154.c test: >> >> (note 7 1 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK) >> (note/s 2 7 3 2 "" NOTE_INSN_DELETED_LABEL 2) >> (insn 3 2 4 2 (set (reg:DI 85) >> (unspec:DI [ >> (label_ref [2 deleted]) >> ] UNSPEC_SET_RIP)) >> /export/users/ienkovic/issues/4161/gcc/gcc/testsuite/gcc.target/i386/pr55154.c:9 >> -1 >> (insn_list:REG_LABEL_OPERAND 2 (nil))) >> >> There is a REG_LABEL_OPERAND generated but label is still removed. > > Because it should be a REG_LABEL_TARGET? > > AFAUI this is a contol flow insn so I'd expect it to be a jump_insn > (and the note will be a TARGET note). But it's not a PC-set insn and a > jump target the compiler will interpret as an infinite loop (if the > insns are really in the order as above) which is clearly not what you > want. So if you emit it as a jump_insn I'm not sure what will > happen... > > Is it necessary to emit the label into a basic block?
It is not a control flow instruction. It copies value of instruction pointer into a general purpose register. Therefore REG_LABEL_OPERAND seems to be correct. Ilya > > Ciao! > Steven
