[Bug target/112523] New: [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[Bug target/112523] New: [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

            Bug ID: 112523
           Summary: [14 regression] ICE in ipa_push_agg_values_from_jfunc,
                    at ipa-cp.cc:2139
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: build, ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: sayle at gcc dot gnu.org
  Target Milestone: ---
              Host: i386-pc-solaris2.11
            Target: i386-pc-solaris2.11
             Build: i386-pc-solaris2.11

Between 20231110 and 20231123, Solaris/x86 bootstrap got broken: both the 32
and 64-bit libgcc/unwind-dw2.c and unwind-dw2-fde-dip.c cause an ICE:

during IPA pass: inline
/vol/gcc/src/hg/master/local/libgcc/unwind-dw2.c:1472: internal compiler error:
in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139
 1472 |
      |

A reghunt identified this patch

commit 0a140730c970870a5125beb1114f6c01679a040e
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Mon Nov 13 09:05:16 2023 +0000

    i386: Improve reg pressure of double word right shift then truncate.

as the culprit.  I've reduce unwind-dw2.c to the attached testcase.  The
failure can be seen with

cc1 -fpreprocessed unwind-dw2.i -quiet -mtune=generic -march=pentium4 -O2

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

Rainer Orth <ro at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #1 from Rainer Orth <ro at gcc dot gnu.org> ---
Created attachment 56578
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56578&action=edit
reduced testcase

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Rainer Orth from comment #0)
> Between 20231110 and 20231123, Solaris/x86 bootstrap got broken: both the 32
> and 64-bit libgcc/unwind-dw2.c and unwind-dw2-fde-dip.c cause an ICE:

What stage does the ICE show up at? after stage 1 or stage 2?

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=112518

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I suspect PR 112518 was also caused by that same commit too.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #4 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
> (In reply to Rainer Orth from comment #0)
>> Between 20231110 and 20231123, Solaris/x86 bootstrap got broken: both the 32
>> and 64-bit libgcc/unwind-dw2.c and unwind-dw2-fde-dip.c cause an ICE:
>
> What stage does the ICE show up at? after stage 1 or stage 2?

Ah, I forgot: building the stage 2 libgcc; stage 1 is fine.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This also caused some new libstdc++ FAILs:

FAIL: 20_util/duration/io.cc  -std=gnu++20 execution test
FAIL: 20_util/to_chars/1.cc  -std=gnu++17 execution test


For the first one the failure is:

/home/jwakely/src/gcc/gcc/libstdc++-v3/testsuite/20_util/duration/io.cc:62:
void test_format(): Assertion 's == "01:23:45 = 01:23:45"' failed.

The string s contains "01:00:45 = 01:23:45" instead of the expected contents.

Reverting 0a140730c970870a5125beb1114f6c01679a040e fixes both FAILs.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

Sam James <sjames at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-11-14
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #6 from Sam James <sjames at gcc dot gnu.org> ---
Confirming via
https://inbox.sourceware.org/gcc-regression/20231114032959.06B94180042@gnu-snb-1.sc.intel.com/T/#u
and jwakely's comment.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Trying now
2023-11-14  Jakub Jelinek  <jakub@redhat.com>

        * config/i386/i386.md (<insn><dwi>3_doubleword_lowpart): Move
        operands[1] aka low part of input rather than operands[3] aka high
        part of input to output if not the same register.

--- gcc/config/i386/i386.md.jj  2023-11-14 08:10:18.932549803 +0100
+++ gcc/config/i386/i386.md     2023-11-14 09:31:05.565019207 +0100
@@ -14825,8 +14825,8 @@ (define_insn_and_split "<insn><dwi>3_dou
 {
   split_double_mode (<DWI>mode, &operands[1], 1, &operands[1], &operands[3]);
   operands[4] = GEN_INT ((<MODE_SIZE> * BITS_PER_UNIT) - INTVAL
(operands[2]));
-  if (!rtx_equal_p (operands[0], operands[3]))
-    emit_move_insn (operands[0], operands[3]);
+  if (!rtx_equal_p (operands[0], operands[1]))
+    emit_move_insn (operands[0], operands[1]);
 })

 (define_insn "x86_64_shrd"
if it fixes this.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[ro at CeBiTec dot Uni-Bielefeld.DE]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #8 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> ---
> --- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
> Trying now
> 2023-11-14  Jakub Jelinek  <jakub@redhat.com>
>
>         * config/i386/i386.md (<insn><dwi>3_doubleword_lowpart): Move
>         operands[1] aka low part of input rather than operands[3] aka high
>         part of input to output if not the same register.
[...]
> if it fixes this.

With this patch, I could complete a i386-pc-solaris2.11 bootstrap (C/C++
only).

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
My i686-linux bootstrap also finished with that patch (failed without it), but
regtest is still pending (and x86_64-linux bootstrap is ongoing too).

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The patch fixes the libstdc++ tests too.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

--- Comment #11 from CVS 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:aad65285a1c681feb9fc5b041c86d841b24c3d2a

commit r14-5442-gaad65285a1c681feb9fc5b041c86d841b24c3d2a
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Nov 14 13:19:48 2023 +0100

    i386: Fix up <insn><dwi>3_doubleword_lowpart [PR112523]

    On Sun, Nov 12, 2023 at 09:03:42PM -0000, Roger Sayle wrote:
    > This patch improves register pressure during reload, inspired by PR
97756.
    > Normally, a double-word right-shift by a constant produces a double-word
    > result, the highpart of which is dead when followed by a truncation.
    > The dead code calculating the high part gets cleaned up post-reload, so
    > the issue isn't normally visible, except for the increased register
    > pressure during reload, sometimes leading to odd register assignments.
    > Providing a post-reload splitter, which clobbers a single wordmode
    > result register instead of a doubleword result register, helps (a bit).

    Unfortunately this broke bootstrap on i686-linux, broke all ACATS tests
    on x86_64-linux as well as miscompiled e.g. __floattisf in libgcc there
    as well.

    The bug is that shrd{l,q} instruction expects the low part of the input
    to be the same register as the output, rather than the high part as the
    patch implemented.
      split_double_mode (<DWI>mode, &operands[1], 1, &operands[1],
&operands[3]);
    sets operands[1] to the lo_half and operands[3] to the hi_half, so if
    operands[0] is not the same register as operands[1] (rather than [3]) after
    RA, we should during splitting move operands[1] into operands[0].

    Your testcase:
    > #define MASK60 ((1ul << 60) - 1)
    > unsigned long foo (__uint128_t n)
    > {
    >   unsigned long a = n & MASK60;
    >   unsigned long b = (n >> 60);
    >   b = b & MASK60;
    >   unsigned long c = (n >> 120);
    >   return a+b+c;
    > }

    still has the same number of instructions.

    Bootstrapped/regtested on x86_64-linux (where it e.g. turns
                    === acats Summary ===
    -# of unexpected failures       2328
    +# of expected passes           2328
    +# of unexpected failures       0
    and fixes gcc.dg/torture/fp-int-convert-*timode.c FAILs as well)
    and i686-linux (where it previously didn't bootstrap, but compared to
    Friday evening's bootstrap the testresults are ok).

    2023-11-14  Jakub Jelinek  <jakub@redhat.com>

            PR target/112523
            PR ada/112514
            * config/i386/i386.md (<insn><dwi>3_doubleword_lowpart): Move
            operands[1] aka low part of input rather than operands[3] aka high
            part of input to output if not the same register.

[Bug target/112523] [14 regression] ICE in ipa_push_agg_values_from_jfunc, at ipa-cp.cc:2139 during bootstrap since r14-5385-g0a140730c97087

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112523

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

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

--- Comment #12 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.