[llvm] [RISCV][GISel] Support select G_INSERT_VECTOR_ELT (PR #176687)

[Matt Arsenault via llvm-commits]

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@@ -1515,6 +1515,22 @@ void RISCVInstructionSelector::preISelLower(MachineInstr &MI) {
     MRI->setType(DstReg, sXLen);
     break;
   }
+  case RISCV::G_VMV_S_VL: {
+    Register ScalarReg = MI.getOperand(2).getReg();
+    if (isRegInFprb(ScalarReg)) {
+      MI.setDesc(TII.get(RISCV::G_VFMV_S_F_VL));
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arsenm wrote:

This path is missing the constraint to the register class 

https://github.com/llvm/llvm-project/pull/176687