From a8d9cc870593d3e915ac9184dc0daf1783d4f8a4 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 11 Jan 2005 04:25:13 +0000
Subject: [PATCH] shift X, 0 -> X

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19453 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d173a95fcd4..ef0b0769a06 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -612,6 +612,12 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
       }
       break;
 
+    case ISD::SHL:
+    case ISD::SRL:
+    case ISD::SRA:
+      if (C2 == 0) return N1;
+      break;
+
     case ISD::AND:
       if (!C2) return N2;         // X and 0 -> 0
       if (N2C->isAllOnesValue())
-- 
2.34.1