[Bug rtl-optimization/114044] New: ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[Bug rtl-optimization/114044] New: ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

            Bug ID: 114044
           Summary: ICE: in expand_fn_using_insn, at internal-fn.cc:208
                    with _BitInt() and -O -fno-tree-dce
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
                CC: jakub at gcc dot gnu.org
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 57489
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57489&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O -fno-tree-dce testcase.c 
during RTL pass: expand
testcase.c: In function 'foo':
testcase.c:5:7: internal compiler error: in expand_fn_using_insn, at
internal-fn.cc:208
    5 |   5 | __builtin_stdc_bit_floor(ub256_0) & 4;
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x79b2a7 expand_fn_using_insn
        /repo/gcc-trunk/gcc/internal-fn.cc:208
0xf83d8f expand_call_stmt
        /repo/gcc-trunk/gcc/cfgexpand.cc:2771
0xf83d8f expand_gimple_stmt_1
        /repo/gcc-trunk/gcc/cfgexpand.cc:3932
0xf83d8f expand_gimple_stmt
        /repo/gcc-trunk/gcc/cfgexpand.cc:4077
0xf8a2fe expand_gimple_basic_block
        /repo/gcc-trunk/gcc/cfgexpand.cc:6133
0xf8bfd7 execute
        /repo/gcc-trunk/gcc/cfgexpand.cc:6872
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r14-9117-20240221083607-g5772ea772d1-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/14.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --with-cloog --with-ppl --with-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r14-9117-20240221083607-g5772ea772d1-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.1 20240221 (experimental) (GCC)

[Bug rtl-optimization/114044] ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-02-22
                 CC|                            |pinskia at gcc dot gnu.org

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.


ccp1 leaves around:
.CLZ (3);

So does forwprop1 (if we do -fno-tree-ccp).

So does fre.

So does many passes really.

[Bug rtl-optimization/114044] ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Only DCE removes these kind of stmts.  RTL expansion needs to be forgiving here
but I guess it's bitint lowering failing to catch this call.

[Bug rtl-optimization/114044] ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Smaller testcase:
void
foo (void)
{
  unsigned _BitInt(256) a = 3;
  __builtin_clzg (a);
}

The thing is that in this testcase bitint lowering doesn't even know it should
do anything.
The whole behavior of the pass is keyed on there being any SSA_NAMEs for
middle/large/huge BITINT_TYPE with some extra exceptions (it looks at virtual
SSA_NAMEs to see if there isn't a memory store of a middle+ _BitInt INTEGER_CST
and for scalar floating point SSA_NAMEs if they aren't computed from conversion
from middle+ _BitInt INTEGER_CSTs), and even if the pass for some other reason
triggers in the function,
it will not look at statements which don't have any large+ _BitInt SSA_NAMEs,
or are large+ _BitInt INTEGER_CST store or FLOAT_EXPR from large+ _BitInt
INTEGER_CST or the overflow ifns with _Complex large+ _BitInt result.
We really don't want to lower those ifns like
.CLZ/.CTZ/.CLRSB/.POPCOUNT/.PARITY/.FFS
with INTEGER_CST operands, or after all even say .ADD_OVERFLOW (0, 1) where
just operands are large/huge _BitInt but say _Complex int result, those are all
expected to be folded instead.
Now, if s/^void/int;s/__builtin/return &/' above, we fold it in
gimple_fold_stmt_to_constant_1:
#0  wi::clz (x=...) at ../../gcc/wide-int.cc:2164
#1  0x00000000008a9d9b in fold_const_call_ss (result=0x7fffffffc4e0,
fn=CFN_CLZ, arg=..., precision=32, arg_type=<bitint_type 0x7fffea2db5e8>) at
../../gcc/fold-const-call.cc:1029
#2  0x00000000008aa9a5 in fold_const_call_1 (fn=CFN_CLZ, type=<integer_type
0x7fffea14c5e8 int>, arg=<integer_cst 0x7fffea2e5c18>) at
../../gcc/fold-const-call.cc:1254
#3  0x00000000008ab4d6 in fold_const_call (fn=CFN_CLZ, type=<integer_type
0x7fffea14c5e8 int>, arg=<integer_cst 0x7fffea2e5c18>) at
../../gcc/fold-const-call.cc:1385
#4  0x000000000189d6e0 in gimple_resimplify1 (seq=0x0, res_op=0x7fffffffc980,
valueize=0xf42f7d <valueize_op_1(tree)>) at
../../gcc/gimple-match-exports.cc:925
#5  0x000000000189b419 in gimple_match_op::resimplify (this=0x7fffffffc980,
seq=0x0, valueize=0xf42f7d <valueize_op_1(tree)>) at
../../gcc/gimple-match-exports.cc:111
#6  0x000000000189d5b3 in gimple_simplify (stmt=<gimple_call 0x7fffea13aea0>,
res_op=0x7fffffffc980, seq=0x0, valueize=0xf42f7d <valueize_op_1(tree)>, 
    top_valueize=0xf42f41 <valueize_op(tree)>) at
../../gcc/gimple-match-exports.cc:898
#7  0x000000000090986a in gimple_fold_stmt_to_constant_1 (stmt=<gimple_call
0x7fffea13aea0>, valueize=0xf42f41 <valueize_op(tree)>, gvalueize=0xf42f7d
<valueize_op_1(tree)>)
    at ../../gcc/gimple-fold.cc:7551
#8  0x0000000000f4308a in ccp_fold (stmt=<gimple_call 0x7fffea13aea0>) at
../../gcc/tree-ssa-ccp.cc:1290
#9  0x0000000000f48d1b in evaluate_stmt (stmt=<gimple_call 0x7fffea13aea0>) at
../../gcc/tree-ssa-ccp.cc:2228
or with extra -fno-tree-ccp in:
#0  wi::clz (x=...) at ../../gcc/wide-int.cc:2164
#1  0x00000000008a9d9b in fold_const_call_ss (result=0x7fffffffceb0,
fn=CFN_CLZ, arg=..., precision=32, arg_type=<bitint_type 0x7fffea2db5e8>) at
../../gcc/fold-const-call.cc:1029
#2  0x00000000008aa9a5 in fold_const_call_1 (fn=CFN_CLZ, type=<integer_type
0x7fffea14c5e8 int>, arg=<integer_cst 0x7fffea2e5c18>) at
../../gcc/fold-const-call.cc:1254
#3  0x00000000008ab4d6 in fold_const_call (fn=CFN_CLZ, type=<integer_type
0x7fffea14c5e8 int>, arg=<integer_cst 0x7fffea2e5c18>) at
../../gcc/fold-const-call.cc:1385
#4  0x000000000189d6e0 in gimple_resimplify1 (seq=0x7fffffffd278,
res_op=0x7fffffffd200, valueize=0xf811c3 <fwprop_ssa_val(tree)>) at
../../gcc/gimple-match-exports.cc:925
#5  0x000000000189b419 in gimple_match_op::resimplify (this=0x7fffffffd200,
seq=0x7fffffffd278, valueize=0xf811c3 <fwprop_ssa_val(tree)>) at
../../gcc/gimple-match-exports.cc:111
#6  0x000000000189d5b3 in gimple_simplify (stmt=<gimple_call 0x7fffea13ae10>,
res_op=0x7fffffffd200, seq=0x7fffffffd278, valueize=0xf811c3
<fwprop_ssa_val(tree)>, 
    top_valueize=0xf811c3 <fwprop_ssa_val(tree)>) at
../../gcc/gimple-match-exports.cc:898
#7  0x00000000009060dd in fold_stmt_1 (gsi=0x7fffffffd630, inplace=false,
valueize=0xf811c3 <fwprop_ssa_val(tree)>) at ../../gcc/gimple-fold.cc:6359
#8  0x0000000000906833 in fold_stmt (gsi=0x7fffffffd630, valueize=0xf811c3
<fwprop_ssa_val(tree)>) at ../../gcc/gimple-fold.cc:6525
or with extra -fno-tree-ccp -fno-tree-forwprop in:
#0  wi::clz (x=...) at ../../gcc/wide-int.cc:2164
#1  0x00000000008a9d9b in fold_const_call_ss (result=0x7fffffffcd50,
fn=CFN_CLZ, arg=..., precision=32, arg_type=<bitint_type 0x7fffea2db5e8>) at
../../gcc/fold-const-call.cc:1029
#2  0x00000000008aa9a5 in fold_const_call_1 (fn=CFN_CLZ, type=<integer_type
0x7fffea14c5e8 int>, arg=<integer_cst 0x7fffea2e5c18>) at
../../gcc/fold-const-call.cc:1254
#3  0x00000000008ab4d6 in fold_const_call (fn=CFN_CLZ, type=<integer_type
0x7fffea14c5e8 int>, arg=<integer_cst 0x7fffea2e5c18>) at
../../gcc/fold-const-call.cc:1385
#4  0x000000000189d6e0 in gimple_resimplify1 (seq=0x0, res_op=0x7fffffffd1f0,
valueize=0x906784 <no_follow_ssa_edges(tree_node*)>) at
../../gcc/gimple-match-exports.cc:925
#5  0x000000000189b419 in gimple_match_op::resimplify (this=0x7fffffffd1f0,
seq=0x0, valueize=0x906784 <no_follow_ssa_edges(tree_node*)>) at
../../gcc/gimple-match-exports.cc:111
#6  0x000000000189d5b3 in gimple_simplify (stmt=<gimple_call 0x7fffea13ae10>,
res_op=0x7fffffffd1f0, seq=0x0, valueize=0x906784
<no_follow_ssa_edges(tree_node*)>, 
    top_valueize=0x106aeba <rpo_vn_valueize(tree_node*)>) at
../../gcc/gimple-match-exports.cc:898
#7  0x000000000090986a in gimple_fold_stmt_to_constant_1 (stmt=<gimple_call
0x7fffea13ae10>, valueize=0x106aeba <rpo_vn_valueize(tree_node*)>, 
    gvalueize=0x906784 <no_follow_ssa_edges(tree_node*)>) at
../../gcc/gimple-fold.cc:7551
#8  0x000000000106502d in visit_stmt (stmt=<gimple_call 0x7fffea13ae10>,
backedges_varying_p=false) at ../../gcc/tree-ssa-sccvn.cc:6419
etc.
But somehow none of that triggers if the internal fn doesn't have lhs, we just
rely on DCE and DCE can be disabled.
Dunno, shall we just ignore those during expansion if they don't have lhs?

[Bug rtl-optimization/114044] ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 57543
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57543&action=edit
gcc14-pr114044.patch

Untested fix on the ifn expansion side.

[Bug rtl-optimization/114044] ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:c3c44c01d20b00ab5228f32596153b7f4cbc6036

commit r14-9192-gc3c44c01d20b00ab5228f32596153b7f4cbc6036
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Feb 27 09:52:07 2024 +0100

    expand: Add trivial folding for bit query builtins at expansion time
[PR114044]

    While it seems a lot of places in various optimization passes fold
    bit query internal functions with INTEGER_CST arguments to INTEGER_CST
    when there is a lhs, when lhs is missing, all the removals of such dead
    stmts are guarded with -ftree-dce, so with -fno-tree-dce those unfolded
    ifn calls remain in the IL until expansion.  If they have large/huge
    BITINT_TYPE arguments, there is no BLKmode optab and so expansion ICEs,
    and bitint lowering doesn't touch such calls because it doesn't know they
    need touching, functions only containing those will not even be further
    processed by the pass because there are no non-small BITINT_TYPE SSA_NAMEs
    + the 2 exceptions (stores of BITINT_TYPE INTEGER_CSTs and conversions
    from BITINT_TYPE INTEGER_CSTs to floating point SSA_NAMEs) and when walking
    there is no special case for calls with BITINT_TYPE INTEGER_CSTs either,
    those are for normal calls normally handled at expansion time.

    So, the following patch adjust the expansion of these 6 ifns, by doing
    nothing if there is no lhs, and also just in case and user disabled all
    possible passes that would fold this handles the case of setting lhs
    to ifn call with INTEGER_CST argument.

    2024-02-27  Jakub Jelinek  <jakub@redhat.com>

            PR rtl-optimization/114044
            * internal-fn.def (CLRSB, CLZ, CTZ, FFS, PARITY): Use
            DEF_INTERNAL_INT_EXT_FN macro rather than DEF_INTERNAL_INT_FN.
            * internal-fn.h (expand_CLRSB, expand_CLZ, expand_CTZ, expand_FFS,
            expand_PARITY): Declare.
            * internal-fn.cc (expand_bitquery, expand_CLRSB, expand_CLZ,
            expand_CTZ, expand_FFS, expand_PARITY): New functions.
            (expand_POPCOUNT): Use expand_bitquery.

            * gcc.dg/bitint-95.c: New test.

[Bug rtl-optimization/114044] ICE: in expand_fn_using_insn, at internal-fn.cc:208 with _BitInt() and -O -fno-tree-dce

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114044

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed.