[llvm] [X86] combineINSERT_SUBVECTOR - pull out common variables. NFC. (PR #133705)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon created https://github.com/llvm/llvm-project/pull/133705

Reduces diff for an updated version of #133083

>From cc22488b74b84ee402c8a6fe28f40967540c6734 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Mon, 31 Mar 2025 12:22:53 +0100
Subject: [PATCH] [X86] combineINSERT_SUBVECTOR - pull out common variables.
 NFC.

Reduces diff for an updated version of #133083
---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 72977923bac2b..76de7e888d985 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -58823,6 +58823,8 @@ static SDValue combineINSERT_SUBVECTOR(SDNode *N, SelectionDAG &DAG,
 
   uint64_t IdxVal = N->getConstantOperandVal(2);
   MVT SubVecVT = SubVec.getSimpleValueType();
+  int VecNumElts = OpVT.getVectorNumElements();
+  int SubVecNumElts = SubVecVT.getVectorNumElements();
 
   if (Vec.isUndef() && SubVec.isUndef())
     return DAG.getUNDEF(OpVT);
@@ -58882,10 +58884,9 @@ static SDValue combineINSERT_SUBVECTOR(SDNode *N, SelectionDAG &DAG,
       SubVec.getOperand(0).getSimpleValueType() == OpVT &&
       (IdxVal != 0 ||
        !(Vec.isUndef() || ISD::isBuildVectorAllZeros(Vec.getNode())))) {
+    SDValue ExtSrc = SubVec.getOperand(0);
     int ExtIdxVal = SubVec.getConstantOperandVal(1);
     if (ExtIdxVal != 0) {
-      int VecNumElts = OpVT.getVectorNumElements();
-      int SubVecNumElts = SubVecVT.getVectorNumElements();
       SmallVector<int, 64> Mask(VecNumElts);
       // First create an identity shuffle mask.
       for (int i = 0; i != VecNumElts; ++i)
@@ -58893,8 +58894,7 @@ static SDValue combineINSERT_SUBVECTOR(SDNode *N, SelectionDAG &DAG,
       // Now insert the extracted portion.
       for (int i = 0; i != SubVecNumElts; ++i)
         Mask[i + IdxVal] = i + ExtIdxVal + VecNumElts;
-
-      return DAG.getVectorShuffle(OpVT, dl, Vec, SubVec.getOperand(0), Mask);
+      return DAG.getVectorShuffle(OpVT, dl, Vec, ExtSrc, Mask);
     }
   }
 
@@ -58942,7 +58942,7 @@ static SDValue combineINSERT_SUBVECTOR(SDNode *N, SelectionDAG &DAG,
   // If we're splatting the lower half subvector of a full vector load into the
   // upper half, attempt to create a subvector broadcast.
   // TODO: Drop hasOneUse checks.
-  if (IdxVal == (OpVT.getVectorNumElements() / 2) &&
+  if ((int)IdxVal == (VecNumElts / 2) &&
       Vec.getValueSizeInBits() == (2 * SubVec.getValueSizeInBits()) &&
       (Vec.hasOneUse() || SubVec.hasOneUse())) {
     auto *VecLd = dyn_cast<LoadSDNode>(Vec);