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  1. JDK
  2. JDK-8267982

Set the node after peephole optimization to be removed

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    • Subcomponent:
    • Resolved In Build:
      b06
    • CPU:
      other
    • OS:
      linux

      Description

      when I do a peephole optimization like this:

        peephole %{
          peepmatch (storeI loadI storeI loadI);
          peepconstraint (0.src == 1.dst, 2.src == 3.dst, 1.mem == 3.mem);
          peepreplace ( storeII(0.mem 0.mem 2.mem 1.mem 0.src));
        %}



      It crashed on mips64 arch and error infomation are:

      #
      # A fatal error has been detected by the Java Runtime Environment:
      #
      # SIGSEGV (0xb) at pc=0x000000fff5143800, pid=24601, tid=24614
      #
      # JRE version: OpenJDK Runtime Environment (17.0) (build 17-internal+0-adhoc.sunguoyun.jdk-ls-release)
      # Java VM: OpenJDK 64-Bit Server VM (17-internal+0-adhoc.sunguoyun.jdk-ls-release, compiled mode, compressed oops, compressed class ptrs, g1 gc, linux-mips64)
      # Problematic frame:
      # V [libjvm.so+0x2d7800] OopFlow::build_oop_map(Node*, int, PhaseRegAlloc*, int*)+0x238
      #
      # No core dump will be written. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again



      x86_64 maybe have the same issue:
      The nodes (storeI loadI storeI loadI) will be removed after peephole optimization, but the regs of these node be set lived in do_liveness() of buildOopMap.cpp.


      //src/hotspot/share/opto/phaseX.cpp
      2026 void PhasePeephole::do_transform() {
      ...
      2073 for( ; (instruction_index > safe_instruction_index); --instruction_index ) {
      2074 block->remove_node( instruction_index );
      2075 }
      ...

      //src/hotspot/share/opto/buildOopMap.cpp
      404 static void do_liveness(PhaseRegAlloc* regalloc, PhaseCFG* cfg, Block_List* worklist, int max_reg_ints, Arena* A, Dict* safehash) {

      ...
      464 for( uint l=1; l<n->req(); l++ ) {
      465 Node *def = n->in(l); //include removed peephole loadI
      466 assert(def != 0, "input edge required");
      467 int first = regalloc->get_reg_first(def);
      468 int second = regalloc->get_reg_second(def);
      469 if( OptoReg::is_valid(first) ) set_live_bit(tmp_live,first);
      470 if( OptoReg::is_valid(second) ) set_live_bit(tmp_live,second);



      but block`s _defs[] index not include peephole loadI

      //src/hotspot/share/opto/buildOopMap.cpp
      111 void OopFlow::compute_reach( PhaseRegAlloc *regalloc, int max_reg, Dict *safehash ) {
      112
      113 for( uint i=0; i<_b->number_of_nodes(); i++ ) {
      114 Node *n = _b->get_node(i);
      ...

      131 _defs[first] = n;
      132 _defs[second] = n;


      if the blocks before contained-MachSafePoint have no used the same reg for loadI , _defs[reg] will be null in build_oop_map() ,so cause crash


      //src/hotspot/share/opto/buildOopMap.cpp
      210 OopMap *OopFlow::build_oop_map( Node *n, int max_reg, PhaseRegAlloc *regalloc, int* live ) {
      ...
      239 Node *def = _defs[reg]; ---------------->maybe NULL
      240 assert( def, "since live better have reaching def" );
      243 const Type *t = def->bottom_type(); --->crash here

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              Assignee:
              wanghaomin Haomin Wang
              Reporter:
              wanghaomin Haomin Wang
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                Created:
                Updated:
                Resolved: