[Bug debug/94439] New: gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[Bug debug/94439] New: gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

            Bug ID: 94439
           Summary: gcc: error:
                    gcc/testsuite/gcc.dg/torture/builtin-complex-1.c:
                    ‘-fcompare-debug’ failure since
                    r10-3499-g0ce77f463d1d150e
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: jakub at gcc dot gnu.org
  Target Milestone: ---

The following causes -fdebug-compare:

$ gcc
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/torture/builtin-complex-1.c
-fcompare-debug -flive-patching=inline-clone -O2 -funroll-loops
-fno-tree-forwprop -fno-expensive-optimizations -mstack-arg-probe 
gcc: error:
/home/marxin/Programming/gcc/gcc/testsuite/gcc.dg/torture/builtin-complex-1.c:
‘-fcompare-debug’ failure

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |richard.sandiford at linaro dot or
                   |                            |g
      Known to fail|                            |10.0
            Summary|gcc: error:                 |[10 Regression] gcc: error:
                   |gcc/testsuite/gcc.dg/tortur |gcc/testsuite/gcc.dg/tortur
                   |e/builtin-complex-1.c:      |e/builtin-complex-1.c:
                   |‘-fcompare-debug’ failure   |‘-fcompare-debug’ failure
                   |since                       |since
                   |r10-3499-g0ce77f463d1d150e  |r10-3499-g0ce77f463d1d150e
      Known to work|                            |9.3.0
   Last reconfirmed|                            |2020-4-1
   Target Milestone|---                         |10.0

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Slightly reduced testcase:
extern void exit (int);
extern void abort (void);

#define COMPARE_BODY(A, B, TYPE, COPYSIGN)                              \
  do {                                                                  \
    TYPE s1 = COPYSIGN ((TYPE) 1.0, A);                                 \
    TYPE s2 = COPYSIGN ((TYPE) 1.0, B);                                 \
    if (s1 != s2)                                                       \
      abort ();                                                         \
    if ((__builtin_isnan (A) != 0) != (__builtin_isnan (B) != 0))       \
      abort ();                                                         \
    if ((A != B) != (__builtin_isnan (A) != 0))                         \
      abort ();                                                         \
  } while (0)

void
comparel (long double a, long double b)
{
  COMPARE_BODY (a, b, long double, __builtin_copysignl);
}

void
comparecl (_Complex long double a, long double r, long double i)
{
  comparel (__real__ a, r);
  comparel (__imag__ a, i);
}

#define VERIFY(A, B, TYPE, COMPARE)                     \
  do {                                                  \
    TYPE a = A;                                         \
    TYPE b = B;                                         \
    _Complex TYPE cr = __builtin_complex (a, b);        \
    static _Complex TYPE cs = __builtin_complex (A, B); \
    COMPARE (cr, A, B);                                 \
    COMPARE (cs, A, B);                                 \
  } while (0)

#define ALL_CHECKS(PZ, NZ, NAN, INF, TYPE, COMPARE)     \
  do {                                                  \
    VERIFY (NAN, NZ, TYPE, COMPARE);                    \
    VERIFY (INF, NZ, TYPE, COMPARE);                    \
    VERIFY (INF, NAN, TYPE, COMPARE);                   \
    VERIFY (INF, INF, TYPE, COMPARE);                   \
  } while (0)

void
check_long_double (void)
{
  ALL_CHECKS (0.0l, -0.0l, __builtin_nanl(""), __builtin_infl(), long double,
comparecl);
}

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This diverges during sched2, on the reduced testcase with additional
--param=min-nondebug-insn-uid=10000 I see:
-(insn 10076 10075 10055 2 (set (reg:SI 43 r15)
-        (mem/c:SI (const:DI (plus:DI (symbol_ref:DI ("cs.0") [flags 0x2] 
<var_decl 0x7f4364f38900 cs>)
+(insn 10076 10075 221 2 (set (reg:SI 40 r12)
+        (mem/c:SI (const:DI (plus:DI (symbol_ref:DI ("cs.0") [flags 0x2] 
<var_decl 0x7f4bee787900 cs>)
                     (const_int 24 [0x18]))) [1 cs+24 S4 A64]))
"builtin-complex-1.c":50:3 67 {*movsi_internal}
      (nil))
difference between -g0 and -g.

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aoliva at gcc dot gnu.org,
                   |                            |rsandifo at gcc dot gnu.org,
                   |                            |vmakarov at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I'm afraid scheduler -fcompare-debug issues are something I need to give up on.

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at redhat dot com

--- Comment #4 from Jeffrey A. Law <law at redhat dot com> ---
I can probably take a stab.  It's been a long time since I looked at the
scheduler, but there was a time when I knew it reasonably well :-)

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |law at redhat dot com

--- Comment #5 from Jeffrey A. Law <law at redhat dot com> ---
It looks like things go wrong when walking the regrename chains to find the
best renaming possibility.

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

--- Comment #6 from Jeffrey A. Law <law at redhat dot com> ---
And has likely been broken since the introduction of VTA if I'm reading the
code correctly.

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jeff Law <law@gcc.gnu.org>:

https://gcc.gnu.org/g:baf3b9b2e5259558ef86bd62398e2ccecd7a4a4c

commit r10-7789-gbaf3b9b2e5259558ef86bd62398e2ccecd7a4a4c
Author: Jeff Law <law@redhat.com>
Date:   Sat Apr 18 09:39:18 2020 -0600

    Don't let DEBUG_INSNSs change register renaming decisions

            PR debug/94439
            * regrename.c (check_new_reg_p): Ignore DEBUG_INSNs when walking
            the chain.

            PR debug/94439
            * gcc.dg/torture/pr94439.c: New test.

[Bug debug/94439] [10 Regression] gcc: error: gcc/testsuite/gcc.dg/torture/builtin-complex-1.c: ‘-fcompare-debug’ failure since r10-3499-g0ce77f463d1d150e

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94439

Jeffrey A. Law <law at redhat dot com> changed:

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

--- Comment #8 from Jeffrey A. Law <law at redhat dot com> ---
Fixed on the trunk.