Index: lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- lib/Target/AArch64/AArch64InstrInfo.cpp
+++ lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1359,6 +1359,14 @@
   case AArch64::LDRQui:
   case AArch64::LDRXui:
   case AArch64::LDRWui:
+  case AArch64::LDRSWui:
+  // Unscaled instructions.
+  case AArch64::LDURSi:
+  case AArch64::LDURDi:
+  case AArch64::LDURQi:
+  case AArch64::LDURWi:
+  case AArch64::LDURXi:
+  case AArch64::LDURSWi:
     unsigned Width;
     return getMemOpBaseRegImmOfsWidth(LdSt, BaseReg, Offset, Width, TRI);
   };
@@ -1428,6 +1436,7 @@
     Scale = Width = 8;
     break;
   case AArch64::LDRWui:
+  case AArch64::LDRSWui:
   case AArch64::LDRSui:
   case AArch64::STRWui:
   case AArch64::STRSui:
@@ -1452,6 +1461,55 @@
   return true;
 }
 
+// Scale the unscaled offsets.  Returns false if the unscaled offset can't be
+// scaled.
+static bool scaleOffset(unsigned Opc, int64_t &Offset) {
+  unsigned OffsetStride = 1;
+  switch (Opc) {
+  default:
+    return false;
+  case AArch64::LDURQi:
+    OffsetStride = 16;
+    break;
+  case AArch64::LDURXi:
+  case AArch64::LDURDi:
+    OffsetStride = 8;
+    break;
+  case AArch64::LDURWi:
+  case AArch64::LDURSi:
+  case AArch64::LDURSWi:
+    OffsetStride = 4;
+    break;
+  }
+  // If the byte-offset isn't a multiple of the stride, we can't scale this
+  // offset.
+  if (Offset % OffsetStride != 0)
+    return false;
+
+  // Convert the byte-offset used by unscaled into an "element" offset used
+  // by the scaled pair load/store instructions.
+  Offset /= OffsetStride;
+  return true;
+}
+
+static bool canPairLdStOpc(unsigned FirstOpc, unsigned SecondOpc) {
+  if (FirstOpc == SecondOpc)
+    return true;
+  // We can also pair sign-ext and zero-ext instructions.
+  switch (FirstOpc) {
+  default:
+    return false;
+  case AArch64::LDRWui:
+  case AArch64::LDURWi:
+    return SecondOpc == AArch64::LDRSWui || SecondOpc == AArch64::LDURSWi;
+  case AArch64::LDRSWui:
+  case AArch64::LDURSWi:
+    return SecondOpc == AArch64::LDRWui || SecondOpc == AArch64::LDURWi;
+  }
+  // These instructions can't be paired based on their opcodes.
+  return false;
+}
+
 /// Detect opportunities for ldp/stp formation.
 ///
 /// Only called for LdSt for which getMemOpBaseRegImmOfs returns true.
@@ -1461,16 +1519,29 @@
   // Only cluster up to a single pair.
   if (NumLoads > 1)
     return false;
-  if (FirstLdSt->getOpcode() != SecondLdSt->getOpcode())
+
+  // Can we pair these instructions based on their opcodes?
+  unsigned FirstOpc = FirstLdSt->getOpcode();
+  unsigned SecondOpc = SecondLdSt->getOpcode();
+  if (!canPairLdStOpc(FirstOpc, SecondOpc))
     return false;
-  // getMemOpBaseRegImmOfs guarantees that oper 2 isImm.
-  unsigned Ofs1 = FirstLdSt->getOperand(2).getImm();
-  // Allow 6 bits of positive range.
-  if (Ofs1 > 64)
+
+  // getMemOpBaseRegImmOfs guarantees that operand 2 isImm.
+  int64_t Offset1 = FirstLdSt->getOperand(2).getImm();
+  if (isUnscaledLdSt(FirstOpc) && !scaleOffset(FirstOpc, Offset1))
     return false;
+
+  int64_t Offset2 = SecondLdSt->getOperand(2).getImm();
+  if (isUnscaledLdSt(SecondOpc) && !scaleOffset(SecondOpc, Offset2))
+    return false;
+
+  // Pairwise instructions have a 7-bit signed offset field.
+  if (Offset1 > 63 || Offset1 < -64)
+    return false;
+
   // The caller should already have ordered First/SecondLdSt by offset.
-  unsigned Ofs2 = SecondLdSt->getOperand(2).getImm();
-  return Ofs1 + 1 == Ofs2;
+  assert(Offset1 <= Offset2 && "Caller should have ordered offsets.");
+  return Offset1 + 1 == Offset2;
 }
 
 bool AArch64InstrInfo::shouldScheduleAdjacent(MachineInstr *First,
Index: test/CodeGen/AArch64/arm64-ldp-cluster.ll
===================================================================
--- /dev/null
+++ test/CodeGen/AArch64/arm64-ldp-cluster.ll
@@ -0,0 +1,45 @@
+; REQUIRES: asserts
+; RUN: llc < %s -mtriple=arm64-linux-gnu -mcpu=cortex-a57 -verify-misched -debug-only=misched -o - 2>&1 > /dev/null | FileCheck %s
+
+; Test ldpsw clustering
+; CHECK: ********** MI Scheduling **********
+; CHECK: ldp_sext_int:BB#0
+; CHECK: Cluster loads SU(1) - SU(2)
+define i64 @ldp_sext_int(i32* %p) nounwind {
+  %tmp = load i32, i32* %p, align 4
+  %add.ptr = getelementptr inbounds i32, i32* %p, i64 1
+  %tmp1 = load i32, i32* %add.ptr, align 4
+  %sexttmp = sext i32 %tmp to i64
+  %sexttmp1 = sext i32 %tmp1 to i64
+  %add = add nsw i64 %sexttmp1, %sexttmp
+  ret i64 %add
+}
+
+; Test sext + zext loads.
+; CHECK: ********** MI Scheduling **********
+; CHECK: ldp_half_sext_int:BB#0
+; CHECK: Cluster loads SU(3) - SU(4)
+define i64 @ldp_half_sext_int(i64* %q, i32* %p) nounwind {
+  %tmp0 = load i64, i64* %q, align 4
+  %tmp = load i32, i32* %p, align 4
+  %add.ptr = getelementptr inbounds i32, i32* %p, i64 1
+  %tmp1 = load i32, i32* %add.ptr, align 4
+  %sexttmp = sext i32 %tmp to i64
+  %sexttmp1 = zext i32 %tmp1 to i64
+  %add = add nsw i64 %sexttmp1, %sexttmp
+  %add1 = add nsw i64 %add, %tmp0
+  ret i64 %add1
+}
+
+; Test ldur clustering.
+define i32 @ldur_int(i32* %a) nounwind {
+; CHECK: ********** MI Scheduling **********
+; CHECK: ldur_int:BB#0
+; CHECK: Cluster loads SU(2) - SU(1)
+  %p1 = getelementptr inbounds i32, i32* %a, i32 -1
+  %tmp1 = load i32, i32* %p1, align 2
+  %p2 = getelementptr inbounds i32, i32* %a, i32 -2
+  %tmp2 = load i32, i32* %p2, align 2
+  %tmp3 = add i32 %tmp1, %tmp2
+  ret i32 %tmp3
+}