[Bug target/113913] New: [14] RISC-V: suboptimal code gen for intrinsic vcreate

[ewlu at rivosinc dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113913

            Bug ID: 113913
           Summary: [14] RISC-V: suboptimal code gen for intrinsic vcreate
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ewlu at rivosinc dot com
  Target Milestone: ---

godbolt: https://godbolt.org/z/svPsddaTd

Functions like 

vfloat16m2_t
test_vcreate_v_f16m1_f16m2 (vfloat16m1_t v0, vfloat16m1_t v1)
{
  return __riscv_vcreate_v_f16m1_f16m2 (v0, v1);
}

are generating code like

test_vcreate_v_f16m1_f16m2:
        vmv1r.v v11,v8
        vmv1r.v v10,v9
        vmv1r.v v8,v11
        vmv1r.v v9,v10
        ret

which should be optimized away into a nop like later functions in the testcase

test_vcreate_v_i64m2_i64m8:
        ret