[Bug rtl-optimization/106101] New: [12/13 Regression] ICE in reg_bitfield_target_p

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106101

            Bug ID: 106101
           Summary: [12/13 Regression] ICE in reg_bitfield_target_p
           Product: gcc
           Version: 12.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

Testcase reduced from opie

> ./cc1 -quiet /tmp/y.tab.i -O -I include -w
during RTL pass: combine
/tmp/y.tab.i: In function ‘yyparse’:
/tmp/y.tab.i:59:1: internal compiler error: Segmentation fault
   59 | }
      | ^
0x14010ac crash_signal
        /space/rguenther/src/gcc/gcc/toplev.cc:322
0x21932ef reg_bitfield_target_p
        /space/rguenther/src/gcc/gcc/combine.cc:14142
0x219473f distribute_notes
        /space/rguenther/src/gcc/gcc/combine.cc:14653
0x2173f8f try_combine
        /space/rguenther/src/gcc/gcc/combine.cc:4485
0x216a2f6 combine_instructions
        /space/rguenther/src/gcc/gcc/combine.cc:1268
0x2195541 rest_of_handle_combine
        /space/rguenther/src/gcc/gcc/combine.cc:14976
0x2195602 execute
        /space/rguenther/src/gcc/gcc/combine.cc:15021
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