[RISCV] Rematerialize vmv.s.x and vfmv.s.f

Continuing with llvm#107993 and llvm#108007, this handles the last of the main rematerializable vector instructions.

    Program            regalloc.NumSpills                regalloc.NumReloads                regalloc.NumRemats
                       lhs                rhs      diff  lhs                 rhs      diff  lhs                rhs      diff
            508.namd_r  6598.00            6598.00  0.0% 15509.00            15509.00  0.0%  2387.00            2387.00  0.0%
             505.mcf_r   141.00             141.00  0.0%   372.00              372.00  0.0%    36.00              36.00  0.0%
           641.leela_s   356.00             356.00  0.0%   525.00              525.00  0.0%   117.00             117.00  0.0%
       631.deepsjeng_s   353.00             353.00  0.0%   682.00              682.00  0.0%   124.00             124.00  0.0%
       623.xalancbmk_s  1548.00            1548.00  0.0%  2466.00             2466.00  0.0%   620.00             620.00  0.0%
         620.omnetpp_s   946.00             946.00  0.0%  1485.00             1485.00  0.0%  1178.00            1178.00  0.0%
             605.mcf_s   141.00             141.00  0.0%   372.00              372.00  0.0%    36.00              36.00  0.0%
              557.xz_r   289.00             289.00  0.0%   505.00              505.00  0.0%   172.00             172.00  0.0%
           541.leela_r   356.00             356.00  0.0%   525.00              525.00  0.0%   117.00             117.00  0.0%
       531.deepsjeng_r   353.00             353.00  0.0%   682.00              682.00  0.0%   124.00             124.00  0.0%
         520.omnetpp_r   946.00             946.00  0.0%  1485.00             1485.00  0.0%  1178.00            1178.00  0.0%
       523.xalancbmk_r  1548.00            1548.00  0.0%  2466.00             2466.00  0.0%   620.00             620.00  0.0%
             619.lbm_s    68.00              68.00  0.0%    70.00               70.00  0.0%     1.00               1.00  0.0%
             519.lbm_r    73.00              73.00  0.0%    75.00               75.00  0.0%     1.00               1.00  0.0%
              657.xz_s   289.00             289.00  0.0%   505.00              505.00  0.0%   172.00             172.00  0.0%
          511.povray_r  1937.00            1936.00 -0.1%  3629.00             3628.00 -0.0%   517.00             518.00  0.2%
             502.gcc_r 12450.00           12442.00 -0.1% 27328.00            27317.00 -0.0%  9409.00            9409.00  0.0%
             602.gcc_s 12450.00           12442.00 -0.1% 27328.00            27317.00 -0.0%  9409.00            9409.00  0.0%
         638.imagick_s  4181.00            4178.00 -0.1% 11342.00            11338.00 -0.0%  3366.00            3368.00  0.1%
         538.imagick_r  4181.00            4178.00 -0.1% 11342.00            11338.00 -0.0%  3366.00            3368.00  0.1%
       500.perlbench_r  4178.00            4175.00 -0.1%  9162.00             9159.00 -0.0%  2410.00            2410.00  0.0%
       600.perlbench_s  4178.00            4175.00 -0.1%  9162.00             9159.00 -0.0%  2410.00            2410.00  0.0%
            525.x264_r  1886.00            1884.00 -0.1%  4561.00             4559.00 -0.0%   471.00             471.00  0.0%
            625.x264_s  1886.00            1884.00 -0.1%  4561.00             4559.00 -0.0%   471.00             471.00  0.0%
          510.parest_r 42740.00           42689.00 -0.1% 82400.00            82252.00 -0.2%  5612.00            5620.00  0.1%
             644.nab_s   753.00             752.00 -0.1%  1183.00             1182.00 -0.1%   318.00             318.00  0.0%
             544.nab_r   753.00             752.00 -0.1%  1183.00             1182.00 -0.1%   318.00             318.00  0.0%
         526.blender_r 13105.00           13084.00 -0.2% 26478.00            26442.00 -0.1% 18991.00           18989.00 -0.0%
Geomean difference                             -0.0%                              -0.0%                              0.0%

There's an extra spill in one of the test cases, but it's likely noise from the spill weights and isn't an issue in practice.

Author: lukel97

llvm/lib/Target/RISCV/RISCVInstrInfo.cpp

@@ -169,6 +169,8 @@ Register RISCVInstrInfo::isStoreToStackSlot(const MachineInstr &MI,
 bool RISCVInstrInfo::isReallyTriviallyReMaterializable(
     const MachineInstr &MI) const {
   switch (RISCV::getRVVMCOpcode(MI.getOpcode())) {
+  case RISCV::VMV_S_X:
+  case RISCV::VFMV_S_F:
   case RISCV::VMV_V_I:
   case RISCV::VID_V:
     if (MI.getOperand(1).isUndef() &&

llvm/lib/Target/RISCV/RISCVInstrInfoVPseudos.td

@@ -6762,7 +6762,7 @@ let mayLoad = 0, mayStore = 0, hasSideEffects = 0 in {
     Pseudo<(outs GPR:$rd), (ins VR:$rs2, ixlenimm:$sew), []>,
     Sched<[WriteVMovXS, ReadVMovXS]>,
     RISCVVPseudo;
-  let HasVLOp = 1, HasSEWOp = 1, BaseInstr = VMV_S_X,
+  let HasVLOp = 1, HasSEWOp = 1, BaseInstr = VMV_S_X, isReMaterializable = 1,
       Constraints = "$rd = $rs1" in
   def PseudoVMV_S_X: Pseudo<(outs VR:$rd),
                             (ins VR:$rs1, GPR:$rs2, AVL:$vl, ixlenimm:$sew),
@@ -6785,7 +6785,7 @@ let mayLoad = 0, mayStore = 0, hasSideEffects = 0 in {
              (ins VR:$rs2, ixlenimm:$sew), []>,
       Sched<[WriteVMovFS, ReadVMovFS]>,
       RISCVVPseudo;
-    let HasVLOp = 1, HasSEWOp = 1, BaseInstr = VFMV_S_F,
+    let HasVLOp = 1, HasSEWOp = 1, BaseInstr = VFMV_S_F, isReMaterializable = 1,
         Constraints = "$rd = $rs1" in
     def "PseudoVFMV_S_" # f.FX :
       Pseudo<(outs VR:$rd),