Index: lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- lib/Target/X86/X86ISelDAGToDAG.cpp
+++ lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -190,6 +190,7 @@
   private:
     void Select(SDNode *N) override;
 
+    SDValue pruneForLEAExtraction(SDNode *N);
     bool foldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM);
     bool matchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM);
     bool matchWrapper(SDValue N, X86ISelAddressMode &AM);
@@ -699,12 +700,59 @@
   return false;
 }
 
+// Perform DAG pruning to facilitate LEA selection.
+SDValue X86DAGToDAGISel::pruneForLEAExtraction(SDNode *N) {
+  EVT VT = N->getValueType(0);
+  if (!VT.isScalarInteger())
+    return SDValue();
+
+  auto IsValidConstantShift = [=](SDValue Shift) {
+    if (Shift.getOpcode() != ISD::SHL)
+      return false;
+    SDNode *ShiftVal = Shift.getOperand(1).getNode();
+    if (isa<ConstantSDNode>(ShiftVal) &&
+        (cast<ConstantSDNode>(ShiftVal)->getZExtValue() <= 3))
+      return true;
+    return false;
+  };
+
+  SDLoc DL(N);
+  unsigned Opcode = N->getOpcode();
+  if (Opcode == ISD::SUB) {
+    SDValue N0 = N->getOperand(0);
+    SDValue N1 = N->getOperand(1);
+    if (IsValidConstantShift(N0)) {
+      // Following transformation is being done
+      // %1 = SHL X , 2       ->   %1 = SUB 0 , Y
+      // %2 = SUB %1 , Y           %2 = SHL X , 2
+      //                           %3 = ADD %2 , %1
+      SDValue OpsSUB[] = {CurDAG->getConstant(0, DL, VT), N1};
+      SDValue NewSub = CurDAG->getNode(ISD::SUB, DL, VT, OpsSUB);
+      SDValue OpsAdd[] = {N0, NewSub};
+      return CurDAG->getNode(ISD::ADD, DL, VT, OpsAdd);
+    } else if (IsValidConstantShift(N1)) {
+      // Following transformation is being done
+      //  %1 = SHL X , CONST  ->    %1 = SUB 0 , X
+      //  %2 = SUB Y , %1           %2 = SHL %1 , CONST
+      //                            %3 = ADD Y , %2
+      SDValue OpsSUB[] = {CurDAG->getConstant(0, DL, VT), N1.getOperand(0)};
+      SDValue NewSub = CurDAG->getNode(ISD::SUB, DL, VT, OpsSUB);
+      SDValue OpsShift[] = {NewSub, N1.getOperand(1)};
+      SDValue NewShift = CurDAG->getNode(ISD::SHL, DL, VT, OpsShift);
+      SDValue OpsAdd[] = {N0, NewShift};
+      return CurDAG->getNode(ISD::ADD, DL, VT, OpsAdd);
+    }
+  }
+  return SDValue();
+}
+
 void X86DAGToDAGISel::PreprocessISelDAG() {
   // OptFor[Min]Size are used in pattern predicates that isel is matching.
   OptForSize = MF->getFunction().optForSize();
   OptForMinSize = MF->getFunction().optForMinSize();
   assert((!OptForMinSize || OptForSize) && "OptForMinSize implies OptForSize");
 
+  bool TriggerDeadNodesRemoval = false;
   for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
        E = CurDAG->allnodes_end(); I != E; ) {
     SDNode *N = &*I++; // Preincrement iterator to avoid invalidation issues.
@@ -721,6 +769,20 @@
       continue;
     }
 
+    // Look for pattern which could be transformed to facilitate
+    // addressing mode based LEA selection.
+    if (OptForSize) {
+      SDValue NewN = pruneForLEAExtraction(N);
+      if (NewN.getNode()) {
+        --I;
+        CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), NewN);
+        ++I;
+        CurDAG->DeleteNode(N);
+        TriggerDeadNodesRemoval = true;
+        continue;
+      }
+    }
+
     if (OptLevel != CodeGenOpt::None &&
         // Only do this when the target can fold the load into the call or
         // jmp.
@@ -825,6 +887,8 @@
     ++I;
     CurDAG->DeleteNode(N);
   }
+  if (TriggerDeadNodesRemoval)
+    CurDAG->RemoveDeadNodes();
 }
 
 
Index: test/CodeGen/X86/lea-opt.ll
===================================================================
--- test/CodeGen/X86/lea-opt.ll
+++ test/CodeGen/X86/lea-opt.ll
@@ -311,9 +311,10 @@
 define  i32 @test5(i32 %x, i32 %y)  #0 {
 ; CHECK-LABEL: test5:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    addl %esi, %esi
-; CHECK-NEXT:    subl %esi, %edi
-; CHECK-NEXT:    movl %edi, %eax
+; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %esi
+; CHECK-NEXT:    leal (%rdi,%rsi,2), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i32 %y, -2
@@ -338,9 +339,10 @@
 define  i32 @test7(i32 %x, i32 %y)  #0 {
 ; CHECK-LABEL: test7:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    shll $2, %esi
-; CHECK-NEXT:    subl %esi, %edi
-; CHECK-NEXT:    movl %edi, %eax
+; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %esi
+; CHECK-NEXT:    leal (%rdi,%rsi,4), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i32 %y, -4
@@ -352,8 +354,9 @@
 ; CHECK-LABEL: test8:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
-; CHECK-NEXT:    leal (,%rsi,4), %eax
-; CHECK-NEXT:    subl %edi, %eax
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %edi
+; CHECK-NEXT:    leal (%rdi,%rsi,4), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = shl nsw i32 %y, 2
@@ -361,13 +364,13 @@
   ret i32 %sub
 }
 
-
 define  i32 @test9(i32 %x, i32 %y) #0 {
 ; CHECK-LABEL: test9:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    addl %esi, %esi
-; CHECK-NEXT:    subl %esi, %edi
-; CHECK-NEXT:    movl %edi, %eax
+; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %esi
+; CHECK-NEXT:    leal (%rdi,%rsi,2), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i32 -2, %y
@@ -392,9 +395,10 @@
 define  i32 @test11(i32 %x, i32 %y) #0 {
 ; CHECK-LABEL: test11:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    shll $2, %esi
-; CHECK-NEXT:    subl %esi, %edi
-; CHECK-NEXT:    movl %edi, %eax
+; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %esi
+; CHECK-NEXT:    leal (%rdi,%rsi,4), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i32 -4, %y
@@ -406,8 +410,9 @@
 ; CHECK-LABEL: test12:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
-; CHECK-NEXT:    leal (,%rsi,4), %eax
-; CHECK-NEXT:    subl %edi, %eax
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %edi
+; CHECK-NEXT:    leal (%rdi,%rsi,4), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i32 4, %y
@@ -418,9 +423,8 @@
 define  i64 @test13(i64 %x, i64 %y) #0 {
 ; CHECK-LABEL: test13:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    shlq $2, %rsi
-; CHECK-NEXT:    subq %rsi, %rdi
-; CHECK-NEXT:    movq %rdi, %rax
+; CHECK-NEXT:    negq %rsi
+; CHECK-NEXT:    leaq (%rdi,%rsi,4), %rax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i64 -4, %y
@@ -432,8 +436,9 @@
 ; CHECK-LABEL: test14:
 ; CHECK:       # %bb.0: # %entry
 ; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
-; CHECK-NEXT:    leal (,%rsi,4), %eax
-; CHECK-NEXT:    subl %edi, %eax
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %edi
+; CHECK-NEXT:    leal (%rdi,%rsi,4), %eax
 ; CHECK-NEXT:    retq
 entry:
   %mul = mul nsw i32 4, %y
@@ -444,9 +449,11 @@
 define  zeroext i16 @test15(i16 zeroext %x, i16 zeroext %y) #0 {
 ; CHECK-LABEL: test15:
 ; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    shll $3, %esi
-; CHECK-NEXT:    subl %esi, %edi
-; CHECK-NEXT:    movl %edi, %eax
+; CHECK-NEXT:    # kill: def $esi killed $esi def $rsi
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    negl %esi
+; CHECK-NEXT:    leal (%rdi,%rsi,8), %eax
+; CHECK-NEXT:    # kill: def $ax killed $ax killed $eax
 ; CHECK-NEXT:    retq
 entry:
   %conv = zext i16 %x to i32