From ccd7a98f97c7fabaf7ba3ccccaa71d458038d7a1 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Fri, 18 Jun 2021 14:58:47 +0100
Subject: [PATCH] [DAG] SelectionDAG::computeKnownBits - use APInt::insertBits
 to merge subvector knownbits. NFCI.

As noticed on D104472 we can use APInt::insertBits which will avoid a lot of temporary APInt creations
---
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6d2827e8574..c7f22dd3627 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2955,8 +2955,8 @@ KnownBits SelectionDAG::computeKnownBits(SDValue Op, const APInt &DemandedElts,
         Known2 = computeKnownBits(N0, SubDemandedElts.shl(i),
                          Depth + 1);
         unsigned Shifts = IsLE ? i : SubScale - 1 - i;
-        Known.One |= Known2.One.zext(BitWidth).shl(SubBitWidth * Shifts);
-        Known.Zero |= Known2.Zero.zext(BitWidth).shl(SubBitWidth * Shifts);
+        Known.One.insertBits(Known2.One, SubBitWidth * Shifts);
+        Known.Zero.insertBits(Known2.Zero, SubBitWidth * Shifts);
       }
     }