[Bug target/118150] New: Failure to fold NOT+PTEST to NOTS for SVE

[rsandifo at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118150

            Bug ID: 118150
           Summary: Failure to fold NOT+PTEST to NOTS for SVE
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: aarch64-sve, missed-optimization
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rsandifo at gcc dot gnu.org
                CC: tnfchris at gcc dot gnu.org
  Target Milestone: ---
            Target: aarch64*-*-*

#include <arm_sve.h>
int
foo (svbool_t x, int y, int z)
{
  return svptest_any(svptrue_b8(), svnot_z(svptrue_b8(), x)) ? y : z;
}

generates:

foo:
        ptrue   p3.b, all
        not     p0.b, p3/z, p0.b
        ptest   p3, p0.b
        csel    w0, w1, w0, none
        ret

instead of LLVM's:

foo:
        ptrue   p1.b
        nots    p0.b, p1/z, p0.b
        csel    w0, w0, w1, ne
        ret

because we don't have any combiner patterns for NOT+PTEST.

[HT to Tamar for the spot]