From 9bb1be2eecc888cccee7e9c9fc0ca48cf5d6339e Mon Sep 17 00:00:00 2001
From: Nate Begeman <natebegeman@mac.com>
Date: Tue, 14 Jun 2005 03:55:23 +0000
Subject: [PATCH] Commit a small improvement that is already in the x86 and
 ia64 backends to not generate unnecessary register copies.  This improves
 compile time by 2-5% depending on the test.

llvm-svn: 22210
---
 lib/Target/PowerPC/PPC32ISelPattern.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/Target/PowerPC/PPC32ISelPattern.cpp b/lib/Target/PowerPC/PPC32ISelPattern.cpp
index 750161caf8a..5b4c6e58d5c 100644
--- a/lib/Target/PowerPC/PPC32ISelPattern.cpp
+++ b/lib/Target/PowerPC/PPC32ISelPattern.cpp
@@ -1572,6 +1572,11 @@ unsigned ISel::SelectExpr(SDOperand N, bool Recording) {
   SDNode *Node = N.Val;
   MVT::ValueType DestType = N.getValueType();
 
+  if (Node->getOpcode() == ISD::CopyFromReg &&
+      MRegisterInfo::isVirtualRegister(cast<RegSDNode>(Node)->getReg()))
+    // Just use the specified register as our input.
+    return cast<RegSDNode>(Node)->getReg();
+
   unsigned &Reg = ExprMap[N];
   if (Reg) return Reg;