[Bug target/126443] New: Wrong folding of vmaxnmv, vminmv and vpmaxnms and vpminnms intrinsics

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126443

            Bug ID: 126443
           Summary: Wrong folding of vmaxnmv, vminmv and vpmaxnms and
                    vpminnms intrinsics
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ktkachov at gcc dot gnu.org
  Target Milestone: ---
            Target: aarch64

These testcases abort at every level above -O0 and pass at -O0. They also pass
with Clang at all levels:
#include <arm_neon.h>

int
main (void)
{
  /* FPMaxNum ignores the NaN lanes, so the result is 5.0.  */
  float32x4_t a = { __builtin_nanf (""), -3.0f, __builtin_nanf (""), 5.0f };
  if (vmaxnmvq_f32 (a) != 5.0f)
    __builtin_abort ();

  /* FPMaxNum of +0.0 and -0.0 is +0.0.  */
  float32x4_t b = { -0.0f, 0.0f, -0.0f, -0.0f };
  if (__builtin_signbit (vmaxnmvq_f32 (b)))
    __builtin_abort ();

  /* FPMinNum of -0.0 and +0.0 is -0.0.  */
  float64x2_t c = { -0.0, 0.0 };
  if (!__builtin_signbit (vminnmvq_f64 (c)))
    __builtin_abort ();

  return 0;
}


#include <arm_neon.h>

int
main (void)
{
  /* FPMaxNum ignores the NaN operand, so the result is 3.0.  */
  float b1[2] = { __builtin_nanf (""), 3.0f };
  if (vpmaxnms_f32 (vld1_f32 (b1)) != 3.0f)
    __builtin_abort ();

  /* FPMaxNum of {-0.0, +0.0} is +0.0 and FPMinNum of it is -0.0.  */
  float b2[2] = { -0.0f, 0.0f };
  if (__builtin_signbit (vpmaxnms_f32 (vld1_f32 (b2))))
    __builtin_abort ();
  if (!__builtin_signbit (vpminnms_f32 (vld1_f32 (b2))))
    __builtin_abort ();

  return 0;
}

Looks like our folding of these intrinsics ignores their NaN semantics