[RISCV] Remove two unmasked RVV patterns

[frasercrmck]

Summary

These can be selected to unmasked from masked instructions by the
post-process DAG step.

[craig.topper]

LGTM

llvm/lib/Target/RISCV/RISCVInstrInfoVVLPatterns.td

 defm : VPatNarrowShiftSplatExt_WX<riscv_sra_vl, riscv_zext_vl_oneuse, "PseudoVNSRA">;
 defm : VPatNarrowShiftSplatExt_WX<riscv_srl_vl, riscv_sext_vl_oneuse, "PseudoVNSRL">;
 defm : VPatNarrowShiftSplatExt_WX<riscv_srl_vl, riscv_zext_vl_oneuse, "PseudoVNSRL">;
 
 foreach vtiTowti = AllWidenableIntVectors in {
   defvar vti = vtiTowti.Vti;
   defvar wti = vtiTowti.Wti;
   def : Pat<(vti.Vector (riscv_trunc_vector_vl (wti.Vector wti.RegClass:$rs1),
-                                               (vti.Mask true_mask),
-                                               VLOpFrag)),
-            (!cast<Instruction>("PseudoVNSRL_WX_"#vti.LMul.MX)
-                wti.RegClass:$rs1, X0, GPR:$vl, vti.Log2SEW)>;
-  def : Pat<(vti.Vector (riscv_trunc_vector_vl (wti.Vector wti.RegClass:$rs1),
                                                (vti.Mask V0),
                                                VLOpFrag)),
             (!cast<Instruction>("PseudoVNSRL_WX_"#vti.LMul.MX#"_MASK")
                 (vti.Vector (IMPLICIT_DEF)), wti.RegClass:$rs1, X0,
                 (vti.Mask V0), GPR:$vl, vti.Log2SEW, TAIL_AGNOSTIC)>;
 }
 
 // 12.8. Vector Integer Comparison Instructions
foreach fvtiToFWti = AllWidenableFloatVectors in {
     def : Pat<(fvti.Vector (riscv_fpround_vl (fwti.Vector fwti.RegClass:$rs1),
                                              (fwti.Mask V0),
                                              VLOpFrag)),
               (!cast<Instruction>("PseudoVFNCVT_F_F_W_"#fvti.LMul.MX#"_MASK")
                   (fvti.Vector (IMPLICIT_DEF)), fwti.RegClass:$rs1,
                   (fwti.Mask V0), GPR:$vl, fvti.Log2SEW, TAIL_AGNOSTIC)>;
 
     def : Pat<(fvti.Vector (riscv_fncvt_rod_vl (fwti.Vector fwti.RegClass:$rs1),
-                                               (fwti.Mask true_mask),
-                                               VLOpFrag)),
-              (!cast<Instruction>("PseudoVFNCVT_ROD_F_F_W_"#fvti.LMul.MX)
-                  fwti.RegClass:$rs1, GPR:$vl, fvti.Log2SEW)>;
-
-    def : Pat<(fvti.Vector (riscv_fncvt_rod_vl (fwti.Vector fwti.RegClass:$rs1),
                                                (fwti.Mask V0),
                                                VLOpFrag)),
               (!cast<Instruction>("PseudoVFNCVT_ROD_F_F_W_"#fvti.LMul.MX#"_MASK")
                   (fvti.Vector (IMPLICIT_DEF)), fwti.RegClass:$rs1,
                   (fwti.Mask V0), GPR:$vl, fvti.Log2SEW, TAIL_AGNOSTIC)>;
   }
 }