[llvm] [PPC] Change placeholder from `undef` to `poison` (PR #134552)

[Pedro Lobo via llvm-commits]

https://github.com/pedroclobo created https://github.com/llvm/llvm-project/pull/134552

Call `insertelement` on a `poison` value instead of `undef`.

>From 422d6696112a20efbdf75f32a2c8aa72d3561cf8 Mon Sep 17 00:00:00 2001
From: Pedro Lobo <pedro.lobo at tecnico.ulisboa.pt>
Date: Sun, 6 Apr 2025 18:19:30 +0100
Subject: [PATCH] [PPC] Change placeholder from `undef` to `poison`

Call `insertelement` on a `poison` value instead of `undef`.
---
 llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp b/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
index 2a5af3e50af26..3a4c2fcad8c83 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
@@ -126,7 +126,7 @@ PPCTTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
             IC.Builder.CreateBitCast(II.getArgOperand(0), Mask->getType());
         Value *Op1 =
             IC.Builder.CreateBitCast(II.getArgOperand(1), Mask->getType());
-        Value *Result = UndefValue::get(Op0->getType());
+        Value *Result = PoisonValue::get(Op0->getType());
 
         // Only extract each element once.
         Value *ExtractedElts[32];