[llvm] [RISCV][GISel] Add support for G_IS_FPCLASS in F and D extensions (PR #72000)

[Craig Topper via llvm-commits]

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@@ -948,6 +952,56 @@ bool RISCVInstructionSelector::selectFPCompare(MachineInstr &MI,
   return true;
 }
 
+bool RISCVInstructionSelector::selectIsFPClass(MachineInstr &MI,
+                                               MachineIRBuilder &MIB,
+                                               MachineRegisterInfo &MRI) const {
+  Register GISFPCLASS = MI.getOperand(0).getReg();
+  Register Src = MI.getOperand(1).getReg();
+  const MachineOperand &ImmOp = MI.getOperand(2);
+  const unsigned XLen = STI.getXLen();
+  unsigned NewOpc = MRI.getType(Src).getSizeInBits() == 32 ? RISCV::FCLASS_S
+                                                           : RISCV::FCLASS_D;
+
+  // Turn LLVM IR's floating point classes to that in RISCV,
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topperc wrote:

RISCV -> RISC-V.

https://github.com/llvm/llvm-project/pull/72000