[llvm] [RISCV][GISel] Remove unneeded code from RISCVCallLowering::canLowerReturn. NFC (PR #162144)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/162144

This code calculates FirstMaskArgument which used to be an argument to RISCV_CC, but was removed over a year ago.

>From b79e102a6058cc798ff3552bdebeadec50cfd53b Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Mon, 6 Oct 2025 12:40:42 -0700
Subject: [PATCH] [RISCV][GISel] Remove unneeded code from
 RISCVCallLowering::canLowerReturn. NFC

This code calculates FirstMaskArgument which used to be an
argument to RISCV_CC, but was removed over a year ago.
---
 llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp b/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp
index 34026ed5d47a4..ecfb5febaae74 100644
--- a/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp
+++ b/llvm/lib/Target/RISCV/GISel/RISCVCallLowering.cpp
@@ -439,18 +439,6 @@ bool RISCVCallLowering::canLowerReturn(MachineFunction &MF,
   CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs,
                  MF.getFunction().getContext());
 
-  const RISCVSubtarget &Subtarget = MF.getSubtarget<RISCVSubtarget>();
-
-  std::optional<unsigned> FirstMaskArgument = std::nullopt;
-  // Preassign the first mask argument.
-  if (Subtarget.hasVInstructions()) {
-    for (const auto &ArgIdx : enumerate(Outs)) {
-      MVT ArgVT = MVT::getVT(ArgIdx.value().Ty);
-      if (ArgVT.isVector() && ArgVT.getVectorElementType() == MVT::i1)
-        FirstMaskArgument = ArgIdx.index();
-    }
-  }
-
   for (unsigned I = 0, E = Outs.size(); I < E; ++I) {
     MVT VT = MVT::getVT(Outs[I].Ty);
     if (CC_RISCV(I, VT, VT, CCValAssign::Full, Outs[I].Flags[0], CCInfo,