[Bug rtl-optimization/108461] New: '-fcompare-debug' failure (length) w/ -mcpu=e500mc -O2 -ftrapv -fno-expensive-optimizations -fno-guess-branch-probability -fno-tree-dce -fno-tree-dse

[Bug rtl-optimization/108461] New: '-fcompare-debug' failure (length) w/ -mcpu=e500mc -O2 -ftrapv -fno-expensive-optimizations -fno-guess-branch-probability -fno-tree-dce -fno-tree-dse

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108461

            Bug ID: 108461
           Summary: '-fcompare-debug' failure (length) w/ -mcpu=e500mc -O2
                    -ftrapv -fno-expensive-optimizations
                    -fno-guess-branch-probability -fno-tree-dce
                    -fno-tree-dse
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: compare-debug-failure
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: powerpc-e300c3-linux-gnu

Created attachment 54303
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54303&action=edit
gkd diff w/ -m32

gcc 13.0.0 20230115 snapshot (g:05cd79c2420d3fe6d84bad694d9808982112b0f0) fails
-fcompare-debug check when compiling the following testcase w/ -mcpu=e500mc -O2
-fcompare-debug -ftrapv -fno-expensive-optimizations
-fno-guess-branch-probability -fno-tree-dce -fno-tree-dse:

char m;

void
bar (int y)
{
  int a = 1;

  a = 0x3e10 < y + a + 0x3e00;
}

void
foo (char x)
{
  for (x = 0; x < 3; ++x)
    {
      if (m)
        bar (m);

      m = x;
    }
}

% powerpc-e300c3-linux-gnu-gcc-13 -m32 -mcpu=e500mc -O2 -fcompare-debug -ftrapv
-fno-expensive-optimizations -fno-guess-branch-probability -fno-tree-dce
-fno-tree-dse -c oxbijmxo.c
powerpc-e300c3-linux-gnu-gcc-13: error: oxbijmxo.c: '-fcompare-debug' failure
(length)

gkd diff attached.

[Bug rtl-optimization/108461] '-fcompare-debug' failure (length) w/ -mcpu=e500mc -O2 -ftrapv -fno-expensive-optimizations -fno-guess-branch-probability -fno-tree-dce -fno-tree-dse

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108461

--- Comment #1 from Arseny Solokha <asolokha at gmx dot com> ---
Created attachment 54304
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54304&action=edit
gkd diff w/ -m64

Compiling w/ -m64 instead of -m32 yields the attached gkd diff.

This PR can be actually a duplicate of PR108061.

[Bug rtl-optimization/108461] '-fcompare-debug' failure (length) w/ -mcpu=e500mc -O2 -ftrapv -fno-expensive-optimizations -fno-guess-branch-probability -fno-tree-dce -fno-tree-dse

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108461

--- Comment #2 from Arseny Solokha <asolokha at gmx dot com> ---
Created attachment 54540
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54540&action=edit
gkd diff #2

I believe this simpler testcase demonstrates the same issue.

long long int m, n;

void
foo (void)
{
  if (m)
    m = 0;

  n = m = 0;
}

% powerpc-e300c3-linux-gnu-gcc-13 -mcpu=8540 -O2 -fcompare-debug
-fno-expensive-optimizations -fno-tree-dse -c fqrz27ap.c
powerpc-e300c3-linux-gnu-gcc-13: error: fqrz27ap.c: '-fcompare-debug' failure
(length)