diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index c646e54b580..bf6d22414e8 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1281,6 +1281,44 @@ ARMTargetLowering::InsertAtEndOfBasicBlock(MachineInstr *MI,
 //                           ARM Optimization Hooks
 //===----------------------------------------------------------------------===//
 
+/// isLegalAddressingMode - Return true if the addressing mode represented
+/// by AM is legal for this target, for a load/store of the specified type.
+bool ARMTargetLowering::isLegalAddressingMode(const AddrMode &AM, 
+                                              const Type *Ty) const {
+  if (!isLegalAddressImmediate(AM.BaseOffs, Ty))
+    return false;
+  
+  // Can never fold addr of global into load/store.
+  if (AM.BaseGV) 
+    return false;
+  
+  switch (AM.Scale) {
+  case 0:  // no scale reg, must be "r+i" or "r", or "i".
+    break;
+  case 1:
+    if (Subtarget->isThumb())
+      return false;
+
+  default:
+    // FIXME: verify.
+    switch (getValueType(Ty)) {
+    default: return false;
+    case MVT::i1:
+    case MVT::i8:
+    // TODO: i16?  i64 should be i32, no?
+    case MVT::i32:
+      // r + r
+      if (AM.Scale == 2)
+        return true;
+      // r + r << imm
+      if (!isPowerOf2_32(AM.Scale & ~1))
+        return false;
+    }
+    break;
+  }
+  return true;
+}
+
 /// isLegalAddressImmediate - Return true if the integer value can be used
 /// as the offset of the target addressing mode for load / store of the
 /// given type.
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 74790191d76..8846decd9bf 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -80,6 +80,10 @@ namespace llvm {
     virtual MachineBasicBlock *InsertAtEndOfBasicBlock(MachineInstr *MI,
                                                        MachineBasicBlock *MBB);
 
+    /// isLegalAddressingMode - Return true if the addressing mode represented
+    /// by AM is legal for this target, for a load/store of the specified type.
+    virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty)const;
+    
     /// isLegalAddressImmediate - Return true if the integer value can be used
     /// as the offset of the target addressing mode for load / store of the
     /// given type.
diff --git a/lib/Target/PowerPC/PPCISelLowering.cpp b/lib/Target/PowerPC/PPCISelLowering.cpp
index 0d5b6932a7e..4b29bc78862 100644
--- a/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -3199,6 +3199,39 @@ isOperandValidForConstraint(SDOperand Op, char Letter, SelectionDAG &DAG) {
   return TargetLowering::isOperandValidForConstraint(Op, Letter, DAG);
 }
 
+// isLegalAddressingMode - Return true if the addressing mode represented
+// by AM is legal for this target, for a load/store of the specified type.
+bool PPCTargetLowering::isLegalAddressingMode(const AddrMode &AM, 
+                                              const Type *Ty) const {
+  // FIXME: PPC does not allow r+i addressing modes for vectors!
+  
+  // PPC allows a sign-extended 16-bit immediate field.
+  if (AM.BaseOffs <= -(1LL << 16) || AM.BaseOffs >= (1LL << 16)-1)
+    return false;
+  
+  // No global is ever allowed as a base.
+  if (AM.BaseGV)
+    return false;
+  
+  // PPC only support r+r, 
+  switch (AM.Scale) {
+  case 0:  // "r+i" or just "i", depending on HasBaseReg.
+    break;
+  case 1:
+    if (AM.HasBaseReg && AM.BaseOffs)  // "r+r+i" is not allowed.
+      return false;
+    // Otherwise we have r+r or r+i.
+    break;
+  case 2:
+    if (AM.HasBaseReg || AM.BaseOffs)  // 2*r+r  or  2*r+i is not allowed.
+      return false;
+    // Allow 2*r as r+r.
+    break;
+  }
+  
+  return true;
+}
+
 /// isLegalAddressImmediate - Return true if the integer value can be used
 /// as the offset of the target addressing mode for load / store of the
 /// given type.
@@ -3208,7 +3241,7 @@ bool PPCTargetLowering::isLegalAddressImmediate(int64_t V,const Type *Ty) const{
 }
 
 bool PPCTargetLowering::isLegalAddressImmediate(llvm::GlobalValue* GV) const {
-  return TargetLowering::isLegalAddressImmediate(GV); 
+  return false; 
 }
 
 SDOperand PPCTargetLowering::LowerFRAMEADDR(SDOperand Op, SelectionDAG &DAG)
diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index e66d16590bc..593400c2686 100644
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/lib/Target/PowerPC/PPCISelLowering.h
@@ -236,6 +236,10 @@ namespace llvm {
     SDOperand isOperandValidForConstraint(SDOperand Op, char ConstraintLetter,
                                           SelectionDAG &DAG);
 
+    /// isLegalAddressingMode - Return true if the addressing mode represented
+    /// by AM is legal for this target, for a load/store of the specified type.
+    virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty)const;
+    
     /// isLegalAddressImmediate - Return true if the integer value can be used
     /// as the offset of the target addressing mode for load / store of the
     /// given type.
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index fddb4b2b46a..4c54a285cd3 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4047,6 +4047,51 @@ const char *X86TargetLowering::getTargetNodeName(unsigned Opcode) const {
   }
 }
 
+// isLegalAddressingMode - Return true if the addressing mode represented
+// by AM is legal for this target, for a load/store of the specified type.
+bool X86TargetLowering::isLegalAddressingMode(const AddrMode &AM, 
+                                              const Type *Ty) const {
+  // X86 supports extremely general addressing modes.
+  
+  // X86 allows a sign-extended 32-bit immediate field as a displacement.
+  if (AM.BaseOffs <= -(1LL << 32) || AM.BaseOffs >= (1LL << 32)-1)
+    return false;
+  
+  if (AM.BaseGV) {
+    // X86-64 only supports addr of globals in small code model.
+    if (Subtarget->is64Bit() &&
+        getTargetMachine().getCodeModel() != CodeModel::Small)
+      return false;
+    
+    // We can only fold this if we don't need a load either.
+    if (Subtarget->GVRequiresExtraLoad(AM.BaseGV, getTargetMachine(), false))
+      return false;
+  }
+  
+  switch (AM.Scale) {
+  case 0:
+  case 1:
+  case 2:
+  case 4:
+  case 8:
+    // These scales always work.
+    break;
+  case 3:
+  case 5:
+  case 9:
+    // These scales are formed with basereg+scalereg.  Only accept if there is
+    // no basereg yet.
+    if (AM.HasBaseReg)
+      return false;
+    break;
+  default:  // Other stuff never works.
+    return false;
+  }
+  
+  return true;
+}
+
+
 /// isLegalAddressImmediate - Return true if the integer value can be used
 /// as the offset of the target addressing mode for load / store of the
 /// given type.
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 2e43778a3fc..610ea0029cd 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -335,6 +335,10 @@ namespace llvm {
       getRegForInlineAsmConstraint(const std::string &Constraint,
                                    MVT::ValueType VT) const;
     
+    /// isLegalAddressingMode - Return true if the addressing mode represented
+    /// by AM is legal for this target, for a load/store of the specified type.
+    virtual bool isLegalAddressingMode(const AddrMode &AM, const Type *Ty)const;
+
     /// isLegalAddressImmediate - Return true if the integer value can be used
     /// as the offset of the target addressing mode for load / store of the
     /// given type.