[Bug c/112896] New: RISC-V: gcc.dg/pr30957-1.c run failure when rv64gcv_zvl1024b_zvfh_zfh

[Bug c/112896] New: RISC-V: gcc.dg/pr30957-1.c run failure when rv64gcv_zvl1024b_zvfh_zfh

[pan2.li at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112896

            Bug ID: 112896
           Summary: RISC-V: gcc.dg/pr30957-1.c run failure when
                    rv64gcv_zvl1024b_zvfh_zfh
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pan2.li at intel dot com
  Target Milestone: ---

The gcc.dg/pr30957-1.c test case is failed in RISC-V backend when build with
below options.

-march=rv64gcv_zvl1024b_zvfh_zfh -mabi=lp64d  -O2 -mcmodel=medlow
--param=riscv-autovec-preference=fixed-vlmax -funroll-loops -fassociative-math
-fno-trapping-math -fno-signed-zeros -fvariable-expansion-in-unroller
-fdump-rtl-expand-details -lm gcc/testsuite/gcc.dg/pr30957-1.c -o test.elf

The test gcc/testsuite/gcc.dg/pr30957-1.c may be similar as below.

float __attribute__((noinline))
foo (float d, int n)
{
  unsigned i;
  float accum = d;

  for (i = 0; i < n; i++)
    accum += d;

  return accum;
}

int
main ()
{
  /* When compiling standard compliant we expect foo to return -0.0.  But the
     variable expansion during unrolling optimization (for this testcase
enabled
     by non-compliant -fassociative-math) instantiates copy(s) of the
     accumulator which it initializes with +0.0.  Hence we expect that foo
     returns +0.0.  */
  if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != 1.0)
    abort ();
  exit (0);
}

Have an initial investigation that RISC-V backend always get LPT_NONE when
unroll_loops, as the step of loop will be dynamic after vectorizing, and get
the simple loop flag as false, then the pass unroll_loops will do nothing for
non simple loop.

We may need further investigation for this case.

[Bug target/112896] RISC-V: gcc.dg/pr30957-1.c run failure when rv64gcv_zvl1024b_zvfh_zfh

[ewlu at rivosinc dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112896

Edwin Lu <ewlu at rivosinc dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ewlu at rivosinc dot com

--- Comment #1 from Edwin Lu <ewlu at rivosinc dot com> ---
(In reply to Li Pan from comment #0)
> The gcc.dg/pr30957-1.c test case is failed in RISC-V backend when build with
> below options.
> 
> -march=rv64gcv_zvl1024b_zvfh_zfh -mabi=lp64d  -O2 -mcmodel=medlow
> --param=riscv-autovec-preference=fixed-vlmax -funroll-loops
> -fassociative-math -fno-trapping-math -fno-signed-zeros
> -fvariable-expansion-in-unroller -fdump-rtl-expand-details -lm
> gcc/testsuite/gcc.dg/pr30957-1.c -o test.elf
> 
> The test gcc/testsuite/gcc.dg/pr30957-1.c may be similar as below.
> 
> float __attribute__((noinline))
> foo (float d, int n)
> {
>   unsigned i;
>   float accum = d;
> 
>   for (i = 0; i < n; i++)
>     accum += d;
> 
>   return accum;
> }
> 
> int
> main ()
> {
>   /* When compiling standard compliant we expect foo to return -0.0.  But the
>      variable expansion during unrolling optimization (for this testcase
> enabled
>      by non-compliant -fassociative-math) instantiates copy(s) of the
>      accumulator which it initializes with +0.0.  Hence we expect that foo
>      returns +0.0.  */
>   if (__builtin_copysignf (1.0, foo (0.0 / -5.0, 10)) != 1.0)
>     abort ();
>   exit (0);
> }
> 
> Have an initial investigation that RISC-V backend always get LPT_NONE when
> unroll_loops, as the step of loop will be dynamic after vectorizing, and get
> the simple loop flag as false, then the pass unroll_loops will do nothing
> for non simple loop.
> 
> We may need further investigation for this case.

Our postcommit ci recently identified the testcase aborts on several other
configurations now.
Additional targets (linux and newlib): 
- rv64gcv
- rv64 Vector Crypto
- rv64 RVA23U64 Profile
Logs and testsuite report can be found
https://github.com/patrick-rivos/gcc-postcommit-ci/issues/290

[Bug target/112896] RISC-V: gcc.dg/pr30957-1.c run failure when rv64gcv_zvl1024b_zvfh_zfh

[pan2.li at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112896

Li Pan <pan2.li at intel dot com> changed:

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

--- Comment #2 from Li Pan <pan2.li at intel dot com> ---
This testcase is not well designed, removed from upstream and close this
bugzilla.