From 97c94b8fc630b55e17a37481910810639e28d086 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Thu, 6 May 2010 00:02:14 +0000
Subject: [PATCH] In bottom-up mode, defer the materialization of local
 constant values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103139 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/FastISel.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/CodeGen/SelectionDAG/FastISel.cpp b/lib/CodeGen/SelectionDAG/FastISel.cpp
index 078e5fd3c07..9cc6f1b5ec4 100644
--- a/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -84,6 +84,17 @@ unsigned FastISel::getRegForValue(const Value *V) {
   if (Reg != 0)
     return Reg;
 
+  // In bottom-up mode, just create the virtual register which will be used
+  // to hold the value. It will be materialized later.
+  if (IsBottomUp) {
+    Reg = createResultReg(TLI.getRegClassFor(VT));
+    if (isa<Instruction>(V))
+      ValueMap[V] = Reg;
+    else
+      LocalValueMap[V] = Reg;
+    return Reg;
+  }
+
   return materializeRegForValue(V, VT);
 }