[llvm] fix comment typo in ExpandFCOPYSIGN (PR #111489)

[Ralf Jung via llvm-commits]

https://github.com/RalfJung created https://github.com/llvm/llvm-project/pull/111489

I noticed this while following https://github.com/llvm/llvm-project/pull/111269. It makes little sense that FCOPYSIGN would look at the sign of `x`, right? Surely this must be `y`. Also fix the inconsistency where it's sometimes `x` and sometimes `X`.

>From c4bbf10192c404b64a164194561ecc19b7e2b6c7 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post at ralfj.de>
Date: Tue, 8 Oct 2024 08:58:52 +0200
Subject: [PATCH] fix comment typo in ExpandFCOPYSIGN

---
 llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 42d031310d5e02..5d324f50cce457 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1657,7 +1657,7 @@ SDValue SelectionDAGLegalize::ExpandFCOPYSIGN(SDNode *Node) const {
   SDValue SignBit = DAG.getNode(ISD::AND, DL, IntVT, SignAsInt.IntValue,
                                 SignMask);
 
-  // If FABS is legal transform FCOPYSIGN(x, y) => sign(x) ? -FABS(x) : FABS(X)
+  // If FABS is legal transform FCOPYSIGN(x, y) => SignBit(y) ? -FABS(x) : FABS(x)
   EVT FloatVT = Mag.getValueType();
   if (TLI.isOperationLegalOrCustom(ISD::FABS, FloatVT) &&
       TLI.isOperationLegalOrCustom(ISD::FNEG, FloatVT)) {