[llvm] [GlobalISel] Use getCmpLibcallReturnType() for FCMP libcalls (NFC) (PR #226813)

[Kiroo via llvm-commits]

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@@ -1190,19 +1190,20 @@ LegalizerHelper::createFCMPLibcall(MachineInstr &MI,
   const Register DstReg = Cmp->getReg(0);
   LLT DstTy = MRI.getType(DstReg);
   const auto Cond = Cmp->getCond();
+  Type *RetTy = EVT(TLI.getCmpLibcallReturnType()).getTypeForEVT(Ctx);
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zlfn wrote:

I'll give the refactoring a try once this PR is merged.

https://github.com/llvm/llvm-project/pull/226813