[Bug tree-optimization/95694] New: [9/10/11 Regression] ICE in trunc_int_for_mode, at explow.c:59 since r9-7156-g33579b59aaf02eb7

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95694

            Bug ID: 95694
           Summary: [9/10/11 Regression] ICE in trunc_int_for_mode, at
                    explow.c:59 since r9-7156-g33579b59aaf02eb7
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: law at gcc dot gnu.org, rguenth at gcc dot gnu.org
  Target Milestone: ---

Since the revision, I see:

$ gcc /home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/pr68835-2.c
-fno-tree-forwprop -fno-tree-ccp -O1 -fno-tree-dominator-opts -fno-tree-fre
during RTL pass: expand
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/pr68835-2.c: In function
‘foo’:
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/pr68835-2.c:12:11: internal
compiler error: in as_a, at machmode.h:361
   12 |   return w.a;
      |          ~^~
0x647496 scalar_int_mode as_a<scalar_int_mode>(machine_mode)
        /home/marxin/Programming/gcc/gcc/machmode.h:361
0x64c7e6 reduce_to_bit_field_precision
        /home/marxin/Programming/gcc/gcc/expr.c:4521
0xa3e713 expand_expr_real_2(separate_ops*, rtx_def*, machine_mode,
expand_modifier)
        /home/marxin/Programming/gcc/gcc/expr.c:9971
0xa465c1 expand_expr_real_1(tree_node*, rtx_def*, machine_mode,
expand_modifier, rtx_def**, bool)
        /home/marxin/Programming/gcc/gcc/expr.c:10165
0xa4192c expand_expr_real(tree_node*, rtx_def*, machine_mode, expand_modifier,
rtx_def**, bool)
        /home/marxin/Programming/gcc/gcc/expr.c:8469
0xa4192c expand_expr
        /home/marxin/Programming/gcc/gcc/expr.h:282
0xa4192c expand_expr_real_2(separate_ops*, rtx_def*, machine_mode,
expand_modifier)
        /home/marxin/Programming/gcc/gcc/expr.c:8737
0xa465c1 expand_expr_real_1(tree_node*, rtx_def*, machine_mode,
expand_modifier, rtx_def**, bool)
        /home/marxin/Programming/gcc/gcc/expr.c:10165
0x925ee3 expand_expr
        /home/marxin/Programming/gcc/gcc/expr.h:282
0x925ee3 expand_return
        /home/marxin/Programming/gcc/gcc/cfgexpand.c:3611
0x925ee3 expand_gimple_stmt_1
        /home/marxin/Programming/gcc/gcc/cfgexpand.c:3720
0x925ee3 expand_gimple_stmt
        /home/marxin/Programming/gcc/gcc/cfgexpand.c:3847
0x92b20a expand_gimple_basic_block
        /home/marxin/Programming/gcc/gcc/cfgexpand.c:5888
0x92ccb6 execute
        /home/marxin/Programming/gcc/gcc/cfgexpand.c:6572
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

and historically it disappeared in r6-201-geff973a26bfec703.