Index: lib/Target/Lanai/LanaiISelDAGToDAG.cpp
===================================================================
--- lib/Target/Lanai/LanaiISelDAGToDAG.cpp
+++ lib/Target/Lanai/LanaiISelDAGToDAG.cpp
@@ -282,9 +282,27 @@
     return;
   }
 
-  // Instruction Selection not handled by the auto-generated
-  // tablegen selection should be handled here.
+  // Instruction Selection not handled by the auto-generated tablegen selection
+  // should be handled here.
   switch (Opcode) {
+  case ISD::Constant: {
+    ConstantSDNode *ConstNode = cast<ConstantSDNode>(Node);
+    // Materialize zero constants as copies from R0. This allows the coalescer
+    // to propagate these into other instructions.
+    if (ConstNode->isNullValue()) {
+      SDValue New = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), SDLoc(Node),
+                                           Lanai::R0, MVT::i32);
+      return ReplaceNode(Node, New.getNode());
+    }
+    // Materialize all ones constants as copies from R1. This allows the
+    // coalescer to propagate these into other instructions.
+    if (ConstNode->isAllOnesValue()) {
+      SDValue New = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), SDLoc(Node),
+                                           Lanai::R1, MVT::i32);
+      return ReplaceNode(Node, New.getNode());
+    }
+    break;
+  }
   case ISD::FrameIndex:
     selectFrameIndex(Node);
     return;
Index: lib/Target/Lanai/LanaiInstrInfo.td
===================================================================
--- lib/Target/Lanai/LanaiInstrInfo.td
+++ lib/Target/Lanai/LanaiInstrInfo.td
@@ -831,11 +831,6 @@
 // Non-Instruction Patterns
 //===----------------------------------------------------------------------===//
 
-// i32 0 and R0 can be used interchangeably.
-def : Pat<(i32 0), (i32 R0)>;
-// i32 -1 and R1 can be used interchangeably.
-def : Pat<(i32 -1), (i32 R1)>;
-
 // unsigned 16-bit immediate
 def : Pat<(i32 i32lo16z:$imm), (OR_I_LO (i32 R0), imm:$imm)>;
 
Index: test/CodeGen/Lanai/constant_multiply.ll
===================================================================
--- test/CodeGen/Lanai/constant_multiply.ll
+++ test/CodeGen/Lanai/constant_multiply.ll
@@ -81,18 +81,18 @@
 }
 
 ; CHECK-LABEL: fm9:
-; CHECK: sh %r6, 0x3, %r{{[0-9]+}}
-; CHECK: sub %r{{[0-9]+}}, %r6, %r{{[0-9]+}}
-; CHECK: sub %r{{[0-9]+}}, %r{{[0-9]+}}, %rv
+; CHECK: sub	%r0, %r6, %r{{[0-9]+}}
+; CHECK: sh	%r6, 0x3, %r9
+; CHECK: sub	%r{{[0-9]+}}, %r9, %rv
 define i32 @fm9(i32 inreg %a) #0 {
   %1 = mul nsw i32 %a, -9
   ret i32 %1
 }
 
 ; CHECK-LABEL: fm10:
-; CHECK: sh %r6, 0x3, %r{{[0-9]+}}
 ; CHECK: sh %r6, 0x1, %r{{[0-9]+}}
 ; CHECK: sub %r{{[0-9]+}}, %r{{[0-9]+}}, %r{{[0-9]+}}
+; CHECK: sh %r6, 0x3, %r{{[0-9]+}}
 ; CHECK: sub %r{{[0-9]+}}, %r{{[0-9]+}}, %rv
 define i32 @fm10(i32 inreg %a) #0 {
   %1 = mul nsw i32 %a, -10